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Seismicity and Seismic Hazard for Indian regions

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Seismic Hazard:

The seismic hazard map of India was updated in 2000 (8) by the Bureau of Indian Standards (BIS). There are no major changes in the zones in Orissa with the exception of the merging of Zones I and II in the 1984 BIS map. Districts that lie in the Mahanadi river valley lie in Zone III, and within Orissa this zone stretches from Jharsuguda along the border with Chhatisgarh in a south-easterly direction towards the urban centres of Bhubaneswar and Cuttack on the Mahanadi Delta. The maximum intensity expected in these areas would be around MSK VII. Districts in the north and south-west of the state lie in Zone II.In 1999, the Global Seismic Hazard Assessment Programme (GSHAP) published a map (6) displaying areas that could expect to have a peak ground acceleration (PGA) with a 10% probability of exceedance in 50 years. According to this map, parts of the state of Orissa along the Jharkhand border and along the Andhra-Chatisgarh border can expect a PGA value in the range of 0.04g to 0.06g. A sliver of Balasore district in north-eastern Orissa, along the border with West Bengal can also expect similar values of PGA. Other sections of the state can expect values lower than 0.02g. It must be noted that both, BIS and GSHAP estimate the hazard, based in part, on previous known earthquakes(from unpublished monograph data of Ramalingeswara Rao, 1999 was used for this seismic hazard map of India). Since the earthquake database in India is still incomplete, especially with regards to earthquakes prior to the historical period (before 1800 A.D.), these zones offer a rough guide of the earthquake hazard in any particular region and need to be regularly updated. Based the several factors like geology, Intensities, subsoil conditions and recurrences of earthqukes in region under investigation will be considered and has to be prepared a new update of seismic zones of India.

Seismic Hazard Map of India

Historical seismicity map of India

Seismicity map of India ( source IMD, Magnitudes M>5.0)
Seismicity of the Indian Subcontinent:

Earthquake History ( figure 2 :Historic earthquakes upto 1934)
Largest Earthquake
Seismic Hazard(figure 1 on top)
Significant Earthquakes

Dr. B.Ramalingeswara Rao is kind enough to give his unpblished monograph to this web site seisinfo-india.org
B.RAMALINGESWARA RAO'S WORK ON:- Copy righted:MONOGRAPH ON HISTORY OF INDIAN EARTHQUAKE FROM EARLIEST TO 2005.

PREFACE
To assess the seismic risk, the completeness of the earthquake catalogues especially for the historical background for the Indian regions are essential. In the present monograph, several earthquake catalogues prepared and published by several authors for the Indian regions are scanned. Several authors have carried out an intensive search of the primary sources of historical earthquake occurrence information, for example: Von Hoff, Robert and Mallet, Perrey, Keatings, Burnes, Buist, Middlemiss, Medlicott, Baird-Smith, Montessus De Ballore, Oldham and Iyengar and Sharma etc. Apart from 22 Indian and international earthquake catalogues, 80 descriptions of the felt reports and different catalogues are scanned to identify significant events. Such significant earthquakes of about 50 events during period of 1200 to 1963 AD are described in this monograph to facilitate to understand the seismotectonics and/or geological conditions in different regions. Except Chandra, other authors have not given epicentral locations and uniform magnitudes for the historical earthquakes. The author is trying to fulfill the gaps and lapses in the previous Indian catalogues. In order to properly utilise the earthquake data for research and development, uniform magnitudes are essential. This can be achieved by conversion of maximum intensities into magnitudes using the Gutenberg and Richter’s formula. About 1238 earthquake events have occurred for the last seven and half centuries from 1200AD to 1963AD. Most of the reported or well documented earthquakes are extracted from different scripts, like Persian, Sanskrit and English. Ancient writings of Varahamihira are briefly discussed and expounded. The bibliography of Indian earthquake studies from 1763 to 2002 is also given in appendix 2. THIS WORK IS DEDICATED TO MY PARENTS.
(Dr. Buddha Ramalingeswara Rao)
Hyderabad,
24 March 2000 FOREWORD :
In this monograph, Dr. Buddha Ramalingeswara Rao, has made a laudable contribution by assembling data on past earthquakes in India continental Region from historical times to the later period of instrumental monitoring up to 1963. A bibliography of earthquakes studies since 1763 to 1999 is provided and helps to trace the sources of information. The historical earthquakes have been assigned magnitudes calculated from Intensity- Magnitude relation, thus enhancing the compatibility of the data with data on instrument- monitored earthquakes. The data is illustrated in well-drawn maps for different periods in the records. The monograph would be of immense use in identifying active zones in India and addressing the challenging task of hazard evaluation. With the establishment of several new seismological observatories in the country, one may expect a quantum jump in our capabilities to recognize more earthquake events and estimate the associated energy release. This monograph provides a basis on which all future events may be evaluated. Even more importantly the monograph could provide a guideline to anticipate the safety factor that may be provided for engineering structures in the important in the ground of the known seismicity of their foundations. The author of this monograph, Dr. Buddha Ramalingeswara Rao, NGRI, Hyderabad has several decades of research experience in the field of seismicity and is the author of several outstanding contributions in this field. I trust that the monograph will be received well by the Earth Sciences community in general and by seismologists and civil engineers in particular. I wish the author continued successes in his efforts in understanding earthquakes.
Sd/-
T.M. Mahadevan
(Retd DIRECTOR, ATOMIC MINERAL DVN)

INTRODUCTION:

The study on historical earthquakes and their cataloguing for the Indian subcontinent was initiated by Oldham (1883). He had the five sources of catalogues namely, Robert and Mallet (1858), Perrey (1872), Colonel Keatings (1877, 1878), Baird-Smith (1843, 44), Smith (1843). General catalogues or papers of Buist, Von Hoff and Mallet, Fuchs and Detaille were used by Oldham. Mallet (1810 to 1881), an Ireland engineer who laid down the foundation of instrumental seismology. Mallet (1862) published the first world seismicity map and made systematic attempt to apply physical principles to earthquake effects. He made estimates of the epicentral depth and catalogues in the “ Earthquake catalogue of the British Association”. This catalogue is upto 1842. Annual catalogues of Prof. A. Perrey for the period of 1843 to 1872 were found to be discontinuous with a number of omissions in the catalogue. Colonel Keatings (1877, 1878) had published a list of the shocks felt in Assam from 1874 to 1880. The great Indian earthquake of 12th June 1897 of Assam , was investigated by Oldham (1926). Oldham (1900) had listed 5,319 aftershocks of great earthquake of 12 June 1897 in 14 catalogues of whose epicenters are usually found coinciding with the epicenters of Keatings list of aftershocks. The decline of the frequency of aftershocks followed the unusual law and they continued for atleast 10 years. It is interesting to note that the great Assam earthquake of 1897, had given an opportunity to identify the existence of the Earth’s core which was established by Richard Dixion Oldham, the son of Thomas Oldham (1858 to 1936), in 1906, from observation of earthquake waves. In 1897, Oldham identified on earthquake recordings (seismograms), the three main types of waves predicted by Poisson and Rayleigh, thus confirming that, at least for short period wave motion (dominating periods: 0.1 to 1 sec), the earth indeed behaves like an elastic body for which Hook’s law may apply. Poisson (1829) established the existence of compressional and shear waves in elastic solids and Rayleigh (1885) postulated the surface waves which were later named by them as Rayleigh waves. Oldham (1906) identified on seismograms the above three types of waves from Great Assam earthquake of 12th June 1897. The intensity of the shock within the epicentral track was so large that visible waves were seen at number of places, viz., Shillong, Nalban and Magadai. Thus, the number of seismological findings were initiated and identified in India.

EARTHQUAKE CATALOGUES:

The earthquake history of India in medieval times to nineteenth century is found to be scanty and is in different languages and dispersed in literature. Several authors have attempted to list them in the form of case studies or catalogues. Mention may be made among them are: Baird-Smith (1843, 1844), Robert and Mallet (1858), Perrey (1872), Colonel Keatings (1877,1878), Oldham (1883,1884), Milne (1888, 1912), Middlemiss (1907,1910), Count. F. De Montessus De Ballore (1911), Turner et al (1911,1912, 1913), Bellamy(1931, 1947), West (1937), Krishnan (1938), Pendse (1949), Gutenberg and Richter (1953), Gopal (1953), Tandon (1953), Venkataramanan (1954), Bhan (1955), Richter (1958), Karan Singh (1963), Madhusudana Rao (1966), Srivastava and Somayajulu (1966), Tandon and Chatterjee (1968), Tipnis and Srivastava (1968), Gubin (1968), Kelker (1968), Deshmukh (1968), Rothe (1969), Mukti Nath (1969), Jhingran (1969), Guha et al (1970), Heuckroth and Karim (1970), Arora et al (1970), Choudhury et al (1970), Grade (1971), Karunakaran and Mahadevan (1971), Mukherjee (1971), Kaul (1971), Arora et al (1973), Tandon and Srivastava (1974), Choudhury and Srivastava (1974), Chandra (1977), Gosavi et al (1977), Chaudhury and Srivastava(1978), Kaila and Sarkar (1978), Sharma and Verghese (1979), Quittmeyer and Jacob (1979), Tilak (1980), Indra Mohan et al (1981), Srivastava and Das (1982), Bapat et al (1983), Ramalingeswara Rao and Sitapathi Rao (1984), Srivastava and Ramachandran (1985), Gupta and Singh (1986), Gangrade et al (1987a,b), Krishna Brahmam (1989), Vijay and Murty (1990), Ramachandran and Srivastava (1991), Rastogi (1992), Chandra (1992), Guha and Basu (1993), Narula et al (1996), Gowd et al (1996), Verma et al (1996), Rajendran and Rajendran (1996), Iyengar and Sharma (1996, 1997, 19 98), Srivastava and Dube (1996), Ramalingeswara Rao, (1998), Bansal et al (1998), Malik et al (1999) and Bhattacharya (1999). In addition to the above catalogues, some of the National and International Organisations have also been reported the earthquake occurrence for Indian regions. These include Monthly Weather Reviews: IMD 1891 to 1937; Report of the British Association for the Advancement of Science, 1911; “Seismicity of the Earth” by Gutenberg and Richter (1953); 1904-1916; International Seismological Summary (ISS), 1916-1958; Bulletin Mensural of the Bureau Information de Seismologie (BCIS) 1959-1962, International Seismological Centre (ISC), National Earthquake Information Centre (NEIC), U.S. Coast and Geodetic Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), Hyderabad Seismological Observatory (HYB), Gauribidanur Array (GBA), India Meteorological Department (IMD), Geological Survey of India (GSI), Central Water & Power Research Centre (CWPRC), Gujarat Engineering Research Institute (GERI), Gazetter of Kutchchh District (1971) ,Visakhapatanam Gazetter and Bulletins of the Indian Society of Earthquake Technology, Roorkee. Several anonymous authors had published in different journals and newspapers such as Jour. Asiat. Soc., Bengal, Asiat Jour., Henderson’s Chronological Tables, Official records, Hooker’s Jour. and several newspapers like Statsman, Times of India and Hindustan. Methodology: Several catalogues do not provide information on maximum intensities, magnitudes and/or epicentral locations for historical earthquakes. Guha et al (1970), Guha and Basu (1993) and Chandra (1977, 1992) have given only locations and intensities for historical earthquakes for both Peninsular India and Himalayan regions. In order to get uniformity in the magnitudes in the catalogue, the author used the empirical formula of Gutenberg and Richter. It may be pointed out the maximum intensity (Io) in the MM scale in the epicentral area for the historical shocks has been assessed from the description mentioned in the original literature and the magnitude (M) given as: M = 2/3 Io + 1 Thus, the magnitudes are determined and given in the earthquake catalogue as shown in Table 1. Epicentral locations are determined in this monograph for the historical events based on the macroseismic data. The description of the felt reports at each village indicates 1 or 2 isoseists in the area. If the isoseists are circular in model, the centre is taken as the epicentral location, whereas in the case of elliptical isoseists, the intersection of major and minor axes are taken as the epicentral location. ANCIENT WRITINGS OF VARAHAMIHIRA 505-587 AD

The first report on earthquake prediction in Indian literature written in Sanskrit was reported by Ramalingeswara Rao (1985). Varahamihira discussed earthquakes in 32 slokas ‘verse’) in his great philosophical treatise ‘Brihatsamhita’. He presented observations on anomalous precursor phenomena that occurred before or were supposed to be associated with the earthquake occurrence. These includechanges of weather, lightening, atmospheric changes, ground sound, etc. An important phenomenon, namely, unusual animal behaviour in a short time before an earthquake, was discussed at length in his work. Varahamihira also attempted to ‘classify’ earthquakes into four types, which were named after Hindu Gods. These classifications seem to correspond to some modern categories: Indra (tectonic), Agni (volcanic), Vayu (collapse), and Varuna (hydroseismic activity). According to Varahamihira’s observations, these kinds of earthquakes are generally said to have periods of precursor activity of 1 day, 1, 6 and 8 weeks respectively.

Based on Brihat Samhita (B. S) of Varah Mihira and Adbuta Sagar(A. S) of Balla Sena, Iyengar (1999) have given geographical regions disturbed by earthquakes as shown inFig.(1)and types of earthquakes occurred in different regions as fallows:

Vayu-type earthquake:

B.S. : Saurashtra, Kuru, Magadha, Dasarna, Matsya; A.S.: Yavana, Dandaka, Salva, Sauvardhana, Pulinda, Videha, Nala, Darda, Anga, Vanga, Avanti, Malva, Trgarta, Sauvira, Yaudheya, Ksudraka, Shivika, Madraka, Shaka, Kamboja, Bahlika, Gandhara, Kalinga, Sbara, Mlechha, Tangana.

Agni-type earthquake:

B.S.: Ashmaka, Anga, Bahlika, Tangana, Kalinga, Vanga, Dravida, Shabara: A.S.: Plinda, Yavana, Odhra, Avanti, Iksvaku, Kuluta, Tushara, Shivika, Trigarta, Videha, Surastra, Madhyadesh, Dsarana.

Indra-type earthquake:

Kashi, Yugandhara, Paurava, Kirata, Kira, Abhisara, Hala, Madra, Arbuda, Saurastra, Malva; A.S.: Kashmira, Dravida, Andaka, China, Prachya, Shaka, Pahlava, Dandaka, Kailasa, Malla, Vahala.

Varuna-type earthquake:

B.S.: Gonarda, Chedi, Kukkura, Kirata, Videha; A.S. : Kashmira, Parata, Vasta, Abraka, Karusha, Sinhala.

Vayu-Agni: Kuru, Salva, Matsya, Nishadha, Pundra, Andhra, Kalinga, Vindhya foothills.

Vayu-Indra: Prachya, Shaka, China, Pahlava, Yaudheya, Yavana, Magadha. Vayu-Varuna: Avatika, Pulinda, Videha, Kashmira, Darada.

Agni-Indra: Ikshvaku, Patachara, Abhira, China, Barukacha.

Agni-Varuna: Gonard, Anganrajya, Coastal regions. Indra-Varuna: Kashi, Abhisara, Achyuta, Kachadvipa. SIGNIFICANT HISTORICAL EARTHQUAKES:

In this monograph, the author is trying to focus also on uncatalogued significant and destructive earthquakes, which have been discussed briefly. Several authors have carried out an intensive search of records in archives, memoirs, records of geological investigations and other sources of history are briefly discussed in the present study. In this study about 100 earthquakes are selected on regional geological/tectonic basis in order to understand the recurrence of the earthquake events in the same region. In the following section, the more important earthquakes from 1200AD to 2002AD are described in Fig. (2).

1.WULAR LAKE EARTHQUAKE, 1250 BC:

During the period of King Sundersen, Sindmat Nagar, was struck by a devastating earthquak at night. The entire town was reduced to shables. Cracks appeared on the surface of earthquake and water gushed out and entire town was deluged. The Wular Lake now occupies the site of the city. If the historical tradition is to be believed the MM intensity of this earthquake should be around XII with an epicentral location of 34.6N, 74.5E (Iyengar and Sharma, 1998).

2. BRAHMANABAD EARTHQUAKE 1330 AD:

According to Motessus De Ballore (1911), the great town of Brahmanabad, situated between Karachi and Tattah was overthrown in ruins. The earthquake ruins had been observed by the great traveler Ibn-Batuta in 1333AD. The earthquake may have an intensity of about X MM. The epicentral location may be around 24.1N, 68.0E. The probable year of occurrence may be around 1329 or 1330 in Sindhi district.

3. AGRA EARTHQUAKE, 1505 AD:

On 6th July, 1505 AD, very strong and violent earthquake occurred over the whole of Hindustan that the hills began to tremble, while strong and lofty buildings fell to dust and the earth in places. Cleft and cracks appeared, while villages were deserted. The city of Agra became the goal of several successive aftershocks. The hills began to shake and lofty and solid buildings were razed to ground. It seems that apart from Agra, the cities of Gwalior, this earthquake affected Dholpur, Mathura and Delhi and its influence extended in the whole of the northwest India and to Afghanistan. The epicentral location of this catastrophic earthquake is 27.2N, 78.0E. The MM intensity of the earthquake at Agra might be XII (Iyengar and Sharma, 1998).

4. GARHGAON AND GAJALA EARTHQUAKES: AND ASSAM, 1548, 1596 AD:

A violent earthquake took place in Garghgaon and gajala regions 1548 and 1598 respectively. Both the events have occurred nearby places in Assam in different time periods with common destruction reports. Pebbles, sands and ashes came out bursting the surface of the earth. Their maximum MM intensities were about IX. The epicentral locations for both the earthquakes are at about 26.75N, 94.9E. Iyengar and Sharma (1998) have reported these uncatalogued events in their report. Further, Gait (1905) also mentions the Garhgaon and Gajala destructive earthquakes in his historical report on Assam.

5. SRINAGAR EARTHQUAKE, 1555 AD:

According to Iyengar and Sharma (1996), there was a devastating earthquake in September 1555 AD in the Kashmir valley, during the reign of King Shamsha Shah (1537 - 1559 AD). The epicentral location is around 34.6N, 74.5E.

This earthquake killed many people. It caused holes in the ground and travelers going on their way were misled at every step. Houses fell into these holes at night and people anxious to get out from their houses in the morning, issued by breaking through the roof. This earthquake destroys Hasainapura and Hosainapura. The tributary of the river Jhelum changed its course. The descriptions are indicative of large changes of ground levels and line of sights. The MM intensity could be assigned from description as XII in MM

6. BOMBAY EARTHQUAKE 1618 AD:

Bombay earthquake occurred on 26th May 1618 and accompanied a severe hurricane. 2000 lives and 60 vessels were lost. The epicentral location is 18.9N, 72.9E and maximum MM intensity is IX. (Oldham 1883). But Kelker(1968) had not observed or reported such a big earthquake in his work.

7. MANDARANA EARTHQUAKE 1669 AD: A violent earthquake shocked the area in the vicinity of fort of Mandarana on 4th June 1669. The epicentral location of this event is 22.9N, 87.7E which is very near to Garh Mandaran. The maximum MM intensity is about IX Iyengar and Sharma (1998) have reportd this uncatalogued distructive earthquake in their report. There appeared a crack of 44 yards in length; 2 yards width on the ground and depth of the fissure was about 600 yards (surface rupture depth). After a few days, the crack joined together and topographic of the land changed all of a sudden. The earthquake created large number of fissures but damage is not recorded. Burdwan, Vishnupur, Bankura and west Hubli were reported to be affected largely.

8. SADIYA EARTHQUAKE 1697 AD:

A strong earthquake occurred in Arunachal Pradesh of present times at Sadiya (27.75N, 94.6E). The severe earthquake was followed by number of aftershocks for 6 months in an abortive fashion, from Phagun to Saon. The earth was rent as under at Sadiya. Magur and Kawai fish appeared in the breaches. As sands and water appeared at that place the sides of the hills crumbled down. The description of the effects indicates intensity not less than X (Iyengar and Sharma 1998).

9. GOGA EARTHQUAKE 1705 AD:

In the district of Goga, there was a trembling of the earth that the ground opened for length of about 20 km., in some places fissures were about 30 cubits wide. Goga was a town having a brisk sea trade. It was situated on the eastern shore of Kathiawar peninsula. The MM intensity of this earthquake can be put at XI. Its epicentral location may be at 21.75N, 72.15E (Iyengar and Sharma 1998).

10. DELHI EARTHQUAKE 1720 AD:

A dreadful earthquake took place on 15th July 1720. During the day and night, the houses shook nine or ten times and the ground was going to and fro. It is well known that the walls of the fortress and many houses were destroyed. Several people lost their lives. Aftershocks might have occurred about 4 to 5 months. The felt reports indicate the MM intensity of about X and its epicentral location is around 28.7N, 77.2E near Delhi (Oldham, 1883).

11. CALCUTTA EARTHQUAKE 1737 AD:

The occurrence of this earthquake is debated, though it is reported that 3 lakhs of people perished during this earthquake. Bilham (1994) opined that the same event did not occur due to strong proof is obtained from East India company records. On the other hand, Govinda Rao (1995) had shown the evidence of the occurrence of the Calcutta earthquake on 11 October, 1737 in Gentleman’s magazine and historical chronicle reports thus: A furious Hurricane in the Bay of Bengal, attended with a very heavy rain fall and violent earthquake which threw down abundant houses. Several animal and people perished. The English ships drove offshore and broke to pieces. If this the case of occurrence the catstrophic event in this region of Calcutta, its expected maximum MM intensity may be assigned as X and its epicentral location is probably about 22.6 N, 88.4E.

12. MAHABHALESWAR EARTHQUAKE 1764 AD:

According to Kelkar’s(1968) description in ‘Kesari Daily‘ of 7th Jan, 1968, Marati News Paper. The disastrous earthquake had affected Nasik, Paithan, Rahuri, Pimhgoan, Dhom, Wai, Karad, Pandharpur, Kawthe, Piran, Warna, Mahabhaleswar, Rehmatpur and Pune. Before this earthquake, several tremors had occurred in Kavate, Miran and Warna regions. Neelkhant Mahadev had observed at Sasmadas reddish water come out from the fissures and springs. Based on the felt reports, the maximum MM intensity is about VII and its epicentral location is at 17.9N, 73.7E near Mahabhaleswar.

13. SIRAJGANJ EARTHQUAKE 1787 AD:

Sirajganj in the district of Pabna in Bangladesh, lying on the western bank of the river Jamuna, experienced catastrophic earthquake of 1787. This event shifted the courses of the streams in the region. The maximum MM intensity of this earthquake may be assigned XI. The epicentral location of Sirajganj earthquake is 24.5N, 89.75E (Iyengar and Sharma 1998).

14. ONGOLE EARTHQUAKE 1800 AD:

On 19th October 1800, a severe earthquake occurred in Ongole and lasted nearly a minute. It was also accompanied with violent cyclone (Oldham, 1883). The maximum MM intensity is VI and its epicentral location is 15.6E, 80.1E.

15. MATURA EARTHQUAKE 1803 AD:

A very violent earthquake lasted several minutes. Many pukka buildings were thrown down, very extensive fissures in fields, through which water rose with considerable violence and in quantity sufficient to be used by cultivators. Principal mosques were destroyed and a considerable part of the dome was swallowed up during the opening of the earth. Several aftershocks were followed. Based on the description, the maximum MM intensity is assumed to be IX and its epicentral location is 27.5N, 77.7E (Oldham 1883).

16. SIRMOOR EARTHQUAKE 1803 AD:

A very violent earthquake had occurred in Sirmoor region. About 200 to 300 people were killed at Barbal. Badrinath also suffered severely, several villages swallowed up. It had happened on 1st September 1803 AD. Damage to the Qutub Minar was also noticed. The description of the felt reports indicate the maximum MM intensity of IX and its epicentral location is about 30.3N, 78.8E.

17. MADRAS EARTHQUAKE 1807 AD:

Three distinctive shocks occurred in a middle of cyclone and accompanied by very heavy sea waves. The maximum MM intensity is about VI and its epicentral location is 13.1N, 80.1E(Oldham 1883).

18. KUTCH EARTHQUAKE 1819 AD:

On 16 June 1819, the country was greatly disturbed by the scene of severe earthquakes. North of Sindri and roughly parallel to the northern border of the Rann, the Allah Bond or Dam of God, was formed. The Bond had steep slope rose like a wall above the plain about 16 miles in length. Oldham (1900) had mentioned about the movements of fault and its total displacement amounts to about 20 feet 6 inches. The shock lasted from 2 to 3 minutes with a heavy appalling noise. This earthquake affected several places. Maximum MM intensity is XI and its epicentral location is 23.6N, 69.6E. Bilham(19 ) had studied about this historical earthquake event in detail about its destruction.

19. CHITTORE EARTHQUAKE 1822 AD:

Several shocks occurred in and around Madras, Chittore and Vellore. On 29th June 1882, an earthquake with a very heavy rumbling noise broke up roofs. The maximum MM intensity is VI and its epicentral location is 13.2N; 79.2E(Oldham, 1883).

20. BANGALORE EARTHQUAKE 1829 AD:

Bangalore earthquake occurred on 12 March 1829. Houses much shaken noise like a rushing wind, lasted only for a few seconds. Its maximum MM intensity is V (Oldham, 1883). Its epicentral location is 13.0N, 77.6E. The magnitude is 4.3 on Richter scale.

21. AMARAPOORA EARTHQUAKE 1839 AD:

On 23rd March 1839 a great earthquake visited Amarapoora. Several aftershocks were followed for about six months. In several places great earth fissures were produced 10 to 20 ft., from which large quantities of water and gray earth were thrown out, emitting a sulfurous smell. According to Oldham, (1883), the places in Amarapoora like Ava and Tsagain were destroyed completely and 200 to 300 persons were killed. Based on the description of felt reports, the maximum MM intensity is XI and its epicentral location is 21.9N, 96.0E.

22. BELLARY EARTHQUAKE 1843 AD:

This event was widely extent. At Sholapur, this earthquake was preceded by a noise and lasted in two minutes. Walls of the buldings in towns were thrown down. It effected badly in the regions of Muktal, Singroorgurh, Shorapur, Kurnool and Belgaum. At Bellary, moderate thunder like noise, with undulatory movement and shook the whole cantonment. Bellary was nearest to centre (Oldham, 1883). According to Gubin (1968), this event was felt for few seconds in Kurnool with noise like distant artillery. The Bhima valley and the part of Krishna valley are in the middle of SE elongated isoseismal. Such earthquake could be generated along a fault-zone situated in the above-mentioned valleys. It is a single event earthquake without any foreshocks and aftershocks. The maximum MM intensity is VIII and its epicentral location is 15.2N, 76.9E.

23. NEEBUDDA (near JABALPUR) 1846 AD:

The felt reports indicate that maximum MM intensity of VII and its epicentral location is 23.0N, 80.0E near Jabalpur which is situated on the south fault of Narmada -Son Lineament (NSL). In 1846, the earthquke occurred in this region is a first reoprted earthquake for this region. According to Oldham (1883), the felt reports of the Neebudda earthquake had opened the hill called Dhumohpahari, with a tremendous noise and engulfed trees of immense size.

24. MOUNT ABU EARTHQUAKE 1848 AD:

On 26th April 1848 an earthquake occurred at Mount Abu, with heavy rumbling noise; bungalows all cracked; things thrown from tables and temple of Dilwara much damged. Several aftershocks were also followed (Oldham 1883). The felt reports indicate the maximum MM intensity of about VII and its epicentral location is 24.4N, 72.7E.

25. NORTH ARCOT EARTHQUAKE 1859 AD:

In the Pooloor Taluk, tiles were displaced, and rumbling noise continued for twenty minutes. Also felt in the Wallowanad Taluk of Malabar and the Coimbatore districts (Oldham, 1883). The maximum MM intensity is about VI and its epicentral location is 12.5N, 79.0E.

26. AHAMEDABAD EARTHQUAKE 1864 AD:

This earthquake occurred on 29 April, 1864. Several persons were thrown down. Some felt sick. The earthquake was felt in Surat, Kaira, Mount Abu, etc. The maximum MM intensity is VII, and its magnitude is 5.7. The epicentral location is 22.3N, 72.8E (Chandra, 1977).

27. CONTAI EARTHQUAKE 1866 AD:

This earthquake occurred on 23 January 1866. It is described to be slight but was accompanied by loud rumbling sound like the passage of artillery over a metal road (Oldham, 1883). From the felt reports the maximum MM intensity assigned is VI, and its magnitude is 5.0 on Richter scale. The epicentral location is 21.8N, 87.8E.

28. NELLORE EARTHQUAKE 1869 AD: Nellore earthquake occurred on 1 September 1869, accompanied by a slighter shock also on 2 September 1869. This earthquake is said to be from west to east; walls and posts of the houses were shaken (Oldham, 1883). Based on the felt reports its maximum MM intensity is V and its epicentral location was 14.5N, 80.8E. Its magnitude is 4.3 on Richter scale.

29. SIRONCHA EARTHQUAKE 1872 AD:

No loss of life and no serious damage but the earthquake caused great alarm, many persons ran out of their houses and several were thrown down, direction appeared to be from south to west. (Srivastava and Ramachandran, 1985). Based on the earthquake effects reported in the news papers, they assigned the maximum MM intensity as VI, and its epicentral location is determined by Ramalingeswara Rao (1998) as 18.8N, 80.0E.

30. SECUNDERABAD EARTHQUAKE 1876 AD:

This event was felt throughout the city of Secunderabad in the year 1876. The date of occurrence is not known. It caused general alarm; glass panes were broken in some of the houses, a number of sparrows found dead after the earthquake. Barracks in cantonment area were more or less in an oscillating condition. Based on the earthquake effects Srivastava and Ramachandran (1985) assigned the intensity of VI MM. The epicentral location is determined based on the macroseismic data which is 17.5N, 78.5E.

31. BENGAL EARTHQUAKE 1885 AD:

The great Bengal earthquake of 14th July 1885, was studied by Middlemiss(1885). It was felt with violence throughout the province. Mymensing, Comilla and Sirajgunj bound more devastation. The earthquake affects extended Westwards upto Chotanagapur and Bihar, Northwards into Sikkim and Bhutan Eastwards into Assam, Manipur and Burma. The shock was felt with such considerable violence as to shake loose objects, rattle windows and produce small cracks in double storied houses. Dacca and Pabna, where distraction to buildings was greatest and loss life had occurred. Based on the felt reports, the great earthquake of Bengal may be having a maximum MM intensity of IX and its epicentral location is at Manickgunj, 25.0N, and 92.2E.

32. THE GREAT ASSAM EARTHQUAKE 1897 AD:

According to Oldham (1899), a deep rumbling sound like near thunder, commenced followed immediately by the shock. The ground began to rock violently and in a few seconds it was impossible to stand upright. In the central of the shock there was no master fault or fracture which could be regarded as origin, but a large area over which the disturbance, everywhere great and in many places extreme throughout the greater part of the Garo and Khasi hills, the intensity probably nowhere sank below VIII MM, more usually it reached fully X MM and in places even the XII MM of the extension (Oldham 1926). In this region there were repeated indications of the ground giving raise to changes of levels, faults and fractures of the solid rocks.

33. COIMBATORE EARTHQUAKE 1900 AD:

An earthquake of moderate intensity at its origin near Coimbatore on 8 February 1900 and was widely felt over South India. The maximum intensity in MM scale is about VII and its epicentral location is 10.8N, 76.8E (Basu, 1964).

34. KANGRA EARTHQUAKE 1905 AD:

The earliest large Indian earthquake for which a well documented instrumental magnitude (8.6+) ca be assigned. This was a great disaster; the loss of life is stated as 19,000. Instrumental data are not adequate to fix the epicenter. The meizoseismal are including Kangra was on the territory rocks of the foot hills of the Himalaya. An isolated area of high intensity, lower than that at Kangra but not approached elsewhere, included Debra Dun, also in the foot hills; that was separated from the Kangra meizoseismal area by about 100 miles. The available evidence does not support the idea of two separate earthquakes; it is more likely that there was a great linear extent of faulting. The epicentral location is 33.0N, 76.0E (Richter, 1958). The catastrophic earthquake of Kangra occurred on 4 April 1905 followed by number of aftershocks. The sound was a roar or a crash. People were thrown to the ground. Buildings felt almost instantaneously into utter ruin, and there was very great mortality. Earth fissures and land slides have been observed during the main shock. The drainage river pattern changes its course; and soil cap slides (Middle Miss C.S. 1905).

35. BHAVANAGAR PARA EARTHQUAKE 1919 AD:

The earthquake occurred on 21 April, 1919 and was felt at Bhavanagar Para and several nearby villages. It was also felt at Wadhwan, Sougadh, Chok Jhana and Bhoika. The maximum MM intensity is about VIII and magnitude is 6.2 on Richter scale (Chandra, 1977). The epicentral location is 22.0N, 72.0E.

36. REWA (SON VALLEY) EARTHQUAKE 1927 AD:

This earthquake occurred on 2 June, 1927. Magnitude 6.5, epicenter was 23.83N, 81.0E, in the upper part of the Son valley. Tremors were felt in radius above 350 km., for instance in the Ranchi, Dehri and Allahabad. It is possible, that the intensity in the epicenter was of VII (Tipnis and Srivastava, 1968).

37. BIHAR-NEPAL EARTHQUAKE 1934AD: The disastrous earthquake of Bihar-Nepal occurred on 15 January 1934. About 190 miles long and irregular width exceeding 40 miles area is known as the slump belt which is having an isoseismal of intensity IX-X. The chief criterion adopted in the demarcation of the belt was the behaviours of buildings and other structures. These tilted and slumped bodily into the alluvium, but seldom tumbled brick from brick. Sinking was often differential, in proportion to the relative pressures of the parts of building per unit area. Subsidence of roads causeways and railway embankments were marked, in some cases embankments originally 6 feet high sank down leveled with the surrounding country. Tanks, lakes, borrow pits and other depressions became noticeably shallower as a result of uplift of their bottoms - the tendency on the whole was for elevations and depressions to approach to a common level. Fissuring and emission of sand and water reached their maximum development along this belt. The damage to buildings along this belt is in contrast to that of the area between Muzaffarpur and Dharbhanga, where houses were razed to the ground (Richter, 1958). Based on felt reports the maximum MM intensity assigned is and its epicentral location is

38. QUETTA EARTHQUAKE 1935 AD:

The Quetta earthquake occurred on 31 May, 1935 felt over an area of only 100000 sq. miles, but very severe at the epicenter. About 25000 lives lost and great material damage in Quetta. Exact origin is unknown but the focus was probably shallow. The epicentral location is 29.6N, 65.5E (West 1937).

39. JAIPUR EARTHQUAKE 1935 AD:

Jaipur earthquake occurred on 15 January 1935, accompanied by a subterranean rubbled sound. A solid masonry wall cracked. Duration of the shock was for a few second (Ramachandran and Srivastava, 1991). Based on the felt reports, the maximum MM intensity was V. The epicentral location is 27.0N, 75.9E, and its magnitude is 4.3.

40. HINDUKUSH EARTHQUAKE 1937AD:

This earthquake occurred on 14 November 1937. News has been received of a violent earthquake which occurred at 4-30 PM on Sunday last at Chitran and Drosh, resulting in considerable loss of property and serious damage to the fort. This has necessitated troops being placed under convas. No casualties were reported (Statesman 18th November, 1937 Calcutta edition). The epicentral location is 36.5N, 72.5E. Its maximum MM intensity is VIII+ and magnitude is about 6.0 on Richter scale (Coulson, 1938).

41. SATPURA EARTHQUAKE 1938 AD:

This earthquake occurred on 14 March, 1938. Satpura earthquake Magnitude 6.25, focus at the depth of 50 km, epicenter 21.83N, and 75.75E. Area of maximum intensity was in the Narmada valley and Satpuras. Tremors were felt in radius up to 500 km, for instance in Bombay and Agra. Intensity was: in the Amalner - VI-VII; in Baroda, Barmer and Deesa - IV-V. It is assumed that in the epicenter intensity was up to VIII. Mukherjee determined the magnitude as 5.5, and focal depth 40 km. Before this shock in the Narmada valley were earthquakes: 1847, May 27, near the Dumohpahari hill; 1863, November 18, in the Barwani Country, --walls fell. On July 20, 1935 slight shock originated in the Tapti valley, as it is believed.

42. PALIYAD EARTHQUAKE 1938AD:

A series of earthquake shocks of about 199 had experienced near Paliyad in Kathiwar. The shocks began on 26 June, 1938 and were still continuing on 15 August, 1938. The severe shock on 23rd did much damage in Paliyad. This was felt by most people as far away as Viramgan-Bhavanagar, Morvi and Rajkot, that was over an area of atleast 4,000 sq. miles. The panic due to the weird earthquake noises. Here most of the pukka buildings have been cracked, especially at the corners, and a few have fallen. Based on the felt reports, the maximum MM intensity is VI and its magnitude is 5.0. The epicentral location is 22.25N, 71.6E (Crookshank, 1938).

43. ANDAMAN ISLANDS EARTHQUAKE 1941 AD:

This earthquake occurred on 26 June 1941. The shock was felt very distinctly all over the Andaman Islands; even those driving cars did not fail to notice. Some persons were thrown out of chairs and subsequently they found it difficult to stand up. Some persons standing in the open were obliged to sit down and hold some substantial object. A general sense of alarm was developed. The main shock was lasted for about a minute and caused motions in a west-east direction. The effects of the shock were quite ruinous in the Andaman Island. Bridges embankments, sea walls and jetties also suffered extensive damage. An observer records that the earth opened and close to an extent of several feet and was finally left open about a foot wide (Jingran, 1953). Based on the felt reports, the maximum MM intensity assigned to be XI and the magnitude is 8.1. The epicentral location is 12.4N, 92.5E.

44. ASSAM EARTHQUAKE 1950 AD:

The Assam earthquake of 15 August 1950 is one of the biggest of the twentieth century, so far recorded. It caused wide spread devastation throughout Upper Assam, particularly in the frontier tribal districts of the Mishmi and Abor hills and parts of the Lakkimpur and Sibsagar districts. Approximately, 10,500 sq.miles of the hill area and 8,000 sq.miles of the plains have been affected by the earthquake (Poddar, 1953). Strictly this was not an Indian earthquake; the epicenter was near Rima, in a region claimed by both China and Tibet. It is one of the few earthquakes to which instrumental determined magnitude, 8.7+, is assigned. This shock was more damaging in Assam interms of property loss, than the earthquake of 1897. To the effects of shaking were added those of flood, the river rose high after the earthquake, bringing down sand, mud, trees and all kinds of debris. Pilots flying over the meizoseismal area reported great changes in topography. This was hardly due to the enormous slides, some which were photographed. The only available on the spot account is that of F. Kingdon-Ward, a botanical explorer who was at Rima. However he had little opportunity for observations; he confirms violent shaking at Rima, extensive slides and the rise of streams, but his attention was perforce directed to the difficulties of getting out and back to India. Aftershocks were numerous, many were of magnitude 6 and over and well enough recorded at distant stations were reasonably good epicentral location (Richter, 1958). Its epicentral location is 28.5N, 96.7E. The maximum MM intensity is XII based on the felt reports.

45. KOZHIKODE EARTHQUAKE 1953 AD:

The earthquake occurred on 2 April, 1953, in East of Kottayam district near Kozhikode. This earthquake felt severely. Some buildings shook. The shock was felt in Peered area on the summit of high ranges. Cracks appeared in Ponkunnan post office building. Walls of a nearby church also developed cracks. Wells in the affected area recorded a sharp rise in water level of 4 to 5 feet, while some other springs completely dried up (Ramachandran and Srivastava, 1991). Based on felt reports the maximum MM intensity is VII. The epicentral location is 9.6N, 76.6E.

46. MANIPUR-BURMA EARTHQUAKE 1954AD:

The eastern parts of India including the states of Assam, Manipur, Tripura, West Bengal, Bihar, East Pakistan (Bangladesh) and Burma were rocked by a sharp earthquake on the morning of 22 March 1954. The earthquake was felt strongly at Shillong and lasted for nearly three minutes. The earthquake did not caused any major damage even at places near the epicenter. The epicentral location is 24.5N, 95.0E and its maximum MM intensity reported as VI and with focal depth of 180 Km. (Tandon and Mukherjee, 1956).

47. MYSORE EARTHQUAKE 1955 AD:

Mysore earthquake occurred on 11 July 1955. People rushed out of their houses. Furniture and utensils rattled. The shock was also felt in villages 40 miles around Mysore. Its maximum MM intensity is V (Ramachandran and Srivastava, 1991). The epicentral location is 12.4N, 76.5E.

48. ANJAR EARTHQUAKE 1956AD:

This earthquake occurred on 21 July 1956. Considerable damage occurred at Anjar and a number of villages in the central mainland of Kutch 115 killed, hundreds injured, about 1,350 houses destroyed in Anjar alone and nearby 2,000 suffered minor damage. The earthquake felt as far as away as Bombay in the South, Hyderabad and Thar Parkar districts of Pakistan in the north, Lorwada railway station in the east, and extreme western end of Kutch in the west. The area of maximum damage was confined to about 2,000 sq. kms. in central mainland of Kutch. The radius of perceptibility was about 330 km. The major axis of elliptical isoseismals plotted by Tandon shows a northeast-southwest orientation (Tandon, 1959 and Chandra, 1977). Based on felt reports the maximum MM intensity is IX, and the magnitude is 6.1 (PAS). The epicentral location is 23.0N, 70.0E

49. VIZIANAGARAM EARTHQUAKE 1959 AD:

The earthquake occurred on 29 December, 1959 accompanied by sounds variously described as resembling a distant thunder; booming of an airplane, the noise of heavy moving truck rolling and rumbling sounds underground like a cannon fire or a deep underground explosion (due to number of several earth tremors). Those sleeping on cots were disturbed. Utensils kept on table were thrown down. Rattling of windowpanes was seen. People attending the cinema show in the night came out in panic but were was no damage (Rao, 1966). Based on the felt reports the maximum MM intensity is V and its epicentral location is 18.1E, 83.0N.

50.RATNAGIRI EARTHQUAKE 1962 AD:

The earthquake occurred on 28 September 1962. This shock was felt in the villages Ratnagiri, Sangameswar, Rajapur and Lanja-Mahal taluqs. No damage occurred anywhere. The direction of the movement SW to NE. The shock was for a few seconds shaking the earth and the buildings. The Collector of Ratnagiri district reports no loss or damage. Based on the felt reports, the maximum MM intensity is V and its magnitude is 4.3 on Richter scale. The epicentral location is 17.0N, 73.3E. The focal depth is determined as 16 Km. (Singh and Sethumadhavan, 1963).

AN APPRAISAL OF SEISMOTECTONICS OF THE PENINSULAR INDIA

Introduction:

The Peninsular India has been generally described to be seismically stable. But, the concept of stability of the Indian plate appear to be not valid considering the occurrence of about 10 moderate size earthquakes of magnitude M>6.0 - 6.5 during two centuries. The study of seismotectonics of the Peninsular shield got an impetus after the occurence of the 11th December, 1967 Koyna earthquake, Bhadrachalam earthquake of 13th April, 1969 in the Godavari valley and recent devastating Killari earthquake of 30th September, 1993 in Deccan Volcanic Province. Some workers e.g. Chouhan and Gaur (1968), Gubin (1968,1969), Tandon and Chatterjee (1968), Tandon and Choudhury (1969), Guha et al (1970), Avadh Ram and Rathor (1970), Kaila et al (1972), Chandra (1977), Indra Mohan et al (1981), Gupta et al (1982), Ramalingeswara Rao and Sitapathi Rao (1984), Vijay Kumar and Murty (1990), Rastogi (1992,95), Ramalingeswara Rao (1992, 1994a,b, 1996a,b), Chadha (1992), Krishna Brahmam (1993), Khattri (1994,95), Gupta (1995), Mahadevan (1995), Ramalingeswara Rao and Divakara Rao (1995), Gowd et al (1996), Bhatia and RamalingeswaraRao (1996) and Srivastava and Dube (1996) have worked on various aspects of Indian Shield seismicity and partly dealt with topics to identify the sites of possible reactivation of the old fault patterns, comparing the seismicity of the Indian shield with the seismicity of other parts of the Indian sub-continent etc. Some of them have correlated lithology, heat flow, hot springs etc. with the seismicity of the Indian shield. The map of the epicentral distributions of earthquakes M >2.0 as published by Indra Mohan et al (1981) for the period of 1967-1977 for the Peninsular India reflects, on close examination, the major tectonic belts along the three linear broad zones, 1) Narmada-Tapti-Satpura Lineament (NTSL), 2) an E-W strip between 17oN and 18oN latitude and 3) along low-to high-grade transition zone in the region between 11oN and 13oN. All these three seismic zones are aligned approximately in E-W direction which could be considered roughly parallel to the Himalayan arc (Ramalingeswara Rao 1996). The concept of Mobile belts of the Indian shield has been developed by Radhakrishna and Naqvi (1986) based on the principles laid down by Anhaeusser, et al 1969. Mobile belts are younger, linear metamorphic belts which surround ancient cratonic mobile shield areas and are characterised by high grade metamorphism, granitization and often by transcurrent dislocations. The precambrian mobile belts are nevertheless formed as an integral part of the crystaline shields (Anhaeusser, et al, 1969). It is imperative to investigate the physical process of earthquakes which occur in the hitherto considered stable continental regions such as in Cratons as well as in the Mobile belts in the Peninsular shield. Therefore, it is essential to study the seismotectonics of the Indian shield with a view to understand its nature of stresses and deformation in different seismically active zones, as a result of resistance to the subduction / collison of northern margin of Indian plate against the Eurasian Plate.

The principal horizontal compressive stresses are being exerted from the mid-Indian ocean seismic belts towards the Peninsular shield in three directions i.e. NE, NS and NW (Petroy and Weins, 1989). According to this study, the magnitude of exerted stress can not deform and/or generate new fractures or faults in the intact precambrian rocks in the shield area. The stress, thus injected into the Indian shield gets adjusted in weak zones in the form of strain deformation in the cratons or along the mobile belts of the Peninsular shield (Ramalingeswara Rao, 1994a). The seismogenetic characteristic of the faults in the shield can be divided mainly into two categories i.e. majority strike-slip and occasionally thrust type. From the study of the focal mechanisms, in-situ stress measurements and geodetic studies, it infers that maximum horizontal compressive stresses is prevalent in the Indian Shield. An appraisal of the earlier seismotectonic studies on the Indian shield and recent analysis by the authors in light of the new dataset is presented in this paper.

THE DATA BASE

Historical as well as recent (upto july, 2002) earthquake data of the Peninsular India have been compiled using the data sets of authors such as Oldham (1883), Turner (1911), Milne (1911), Pendse (1949), Banerjee (1957), Tandon and Chettarji (1968), Kelkar (1968), Guha et al (1970), Tandon and Srivastav (1974), Chandra (1977), Indra Mohan et al (1981), Bapat et al (1983), Ramalingeswara Rao and Sitapathi Rao (1984), Srivastava and Ramachandra (1985), Ramachandra and Srivastava (1991) and Guha and Basu (1993). The maximum intensity (Io) in MM scale in the epicentral area for the historical events has been assessed from the description (which may not be always accurate ) mentioned in the original literature and the magnitude (M) have been calculated using formula of Gutenberg - Richter (1954).

M = 1 + 2/3 Io .................(1)

For the historical earthquakes, therefore, magnitudes and locations are only approximate. The structural and geomorphological evolution of the Indian shield was studied by Auden (1949, 1981), Ermenko et. al. (1969) Biswas (1987), Borodin et al (1971), Grady (1971), Kailasam (1975), Katz (1978) and Valdiya (1993) and recently by Rantsman et al, (1994). The earthquake epicenters (M > 3.0) and different faults delineated by the above authors have been plotted in the Fig. 1.

SEISMOTECTONICS OF THE PENINSULAR INDIAN SHIELD

According to Gubin (1968, 69) and Bhaskara Rao and Murthy (1970), the old fault patterns have significant influence over the earthquake occurrence and their study would throw light on the tectonic history of Peninsular India. Gubin (1968), further identified two potential zones for future occurrence of moderate size events for Indain Shield areas near the sites of Bhadrachalam earthquake of April 13, 1969 and Killari earthquake of September 30th, 1993. The concept of block movements in the Peninsular India was proposed by Fermer (1936), Kailasam (1975, 1979, 1993), Radhakrishna (1993), Vaidyanathan (1994) and very recently by Ravi Shankar (1995). According to their opinion, the Indian shield area is tectonically and structurally divisible into large number of faulted blocks which have been differentially moving relative to each other throughout Tertiary, Quarternary and recent times. These movements in turn, have produced stresses which have been responsible for the neo and contemporary tectonism. The existence of the contemporary stress field and stress amplification due to vertical block movement in and around reactivated fault junctions and/or block interfaces is possible.

A close association of seismicity of the Eastern United States with differential vertical crustal moment was reported by Bollinger (1973) and Brown and Oliver (1976). Gubin (1968) cited evidences in support of vertical uplift of the Indian Peninsula during Tertiary and quarternary times. According to him, the rate of uplift is more in western margin of the Peninsula than in its eastern margin and in the northwestern areas it is the largest. Chandra (1977) reported that most of the earthquakes south of 20 0N occur along the coastal regions of the Indian shield. Further, he opined that the edge effect near the continental margin which could be of some significance in causing the earthquakes. Fermer (1936) identified two characteristics of Peninsular Indian shield 1) division of the intrusion of Charnakite series and Non-Charnakitic type linear belts (well known as Fermer's boundary)

2) Greater earthquake susceptibility of Charnakitic regions mostly in Eastern Ghats and regions in Deccan. He, further observed that the Charnakitic region is on the whole more elevated than the non-Charnakitic region. The concept of relative vertical uplift along a belt of weakness, or fault lines or zones, along the junction between the Charnakitic and non- Charnakitic region was also given by him. As evident from fig (Fig.1.), epicenters of magnitudes M> 6.0 have occurred mostly at the intersection of the faults or an active fault region in the mobile belts. In the middle of the Indian cratonic areas a diffused seismicity is observed. The recent shallow cratonic Earthquake of 30th September, 1993 of Ms = 6.3 magnitude in Killari however, has been an exception. The distribution of significant earthquake clusters or swarm of micro - to low magnitude size events have been identified to be occurring in close proximities of the about 200 Alkaline, Anorthosite and Carbonatite magmatic intrusive bodies along the well known S- shaped mobile belt of Indian shield ( Radhakrishna and Naqvi, 1986 and Ramalingeswara Rao, 1994 a). Based on the critical observation of historical as well as recent seismicity, the following three broad seismotectonic zones are defined i) S-shaped mobile belts (S-MB ) comprising a)low to high grade Transition zone (T.Z) in and around areas like Mangalore, Mandya, Bangalore, Dharmpuri, Krishnagiri, Shevroy, Pondichery and Madras (Ramalingeswara Rao ,1992); b) Eastern Ghat mobile belts (EGMB) covering regions near Ongole-Darsi, Visakhapatnam, Vizianagaram and Ganjam ; c) Narmada-Son mobile belt (NSMB) covering Calcutta, Balaghat, Khandwa, Barwani and Broach; d )

Aravalli mobile belt (AMB) covering Ahmedabad, Mount Abu and areas around Delhi ; ii) Cratons comprising a) western Dharwar Craton (WDC), b) Bundelkhand craton (BKC)and c) Sigbhum Craton (SBC); iii) Southern Granulite Terrain (SGT ) comprising region south of transition zone up to southern tip of the peninsula. S- shaped mobile belt regions are seismotectonically moderately active. Cratons in general are relatively inactive but some areas like Koyna in WDC exhibit very high resrevoir induced seismicity.

The southern granulite terrain is also moderately active. We have computed the energy released in different tectonic units of the Indian Shield and observe that about 64% of the earthquake energy release per year is associated with the reservoir induced seismicity especially in Koyna region, 21% in mobile belts, and 15% in the Cratons ( without Koyna region ) and Southern Granulite Panvel Flexure Zone (PFZ) in the west coast of Maharastra bounded between 16o-21o, is also seismically active. The Panvel Flexure Zone, Narmada-Tapti-Son lineament and Aravali intersect each other near Broach. Gubin (1968), Chandra (1977) and Mahadevan (1995) identify this as junction of four seismic zones: NSMB, AMB, PFZ and Cambay Graben. They, further, identified some of them as highly deformed zones of weakness. Ramalingeswara Rao and Sitapathi Rao (1984) have opined that the stability of the Peninsular India is no longer valid because of its moderate historical seismicity. Further, they identified that most of the seismic activity is on the margins of the protocontinental regions: Dharwar, Singhbhum and Aravalli. Whereas, Khattri (1994) hypothesised that the collision of the Indian plate provide N-S compressive strain regime, a part of the strain being released in the major tectonic blocks of the Peninsular shield due to the resistance to the subduction. He, identified nine linear seismic zones which define large blocks in corroboration with the Eremenko et al (1968) tectonic map of India. In similar lines of approach Gowd et al (1996) have also identified that the seismic activity is mostly confined to 8 linear belts, the remaining large area of the shield being stable. This anomalous seismicity of the Indian shield is considered to be due to high intraplate stresses and associated tectonic movements caused by the continental collision between India and Eurasia (Chandra, 1977, Kailasam, 1979, Valdiya, 1989, Raval 1993, Khattri, 1994 and Gowd et al 1996). Mahadevan (1995) has presented an outline of the deep continental structures (DCS) of the Indian shield in relation to seismicity. He has emphasized that the DCS has the potential to constrain genetic aspects of seismicity in continental stable interiors. Accordingly, he divided the Peninsular Shield into 10 different crustal provinces and explained the genesis of the seismicity corresponding to each deep continental structure. The well known low to high grade transition zone (11oN-14oN and 75oE-80oE) was identified as new seismogenic belt found to be associated with moderate seismic actively (Ramalingeswara Rao, 1992) for low magnitude (M 2.0 - 3.0) earthquakes. The diffuse and weak seismicity in the area could be attributed to the reactivation of adjoining shear zones. Temporal variation in seismic activity for the period 1968 - 1986 indicates migration of seismic activity from east to west within transition zone of Peninsular India. Geodynamically, this seismogenic zone has been responding to the forces exerted by plate boundaries and different Indian Ocean deformation belts. The stresses, rheologies and geodynamic models for different deep continental region of the shield is discussed in the later section.

According to Bhatia and Ramalingeswara Rao (1996), there are regular cycles of alternate inactive and active periods with respect to the occurrence of the strong earthquakes of magnitude M > 7.7 in the North Indian plate boundary (NIPB) during 1762 to 1996. It is observed that during the so defined active cycle of NIPB region, the shield is rather inactive in the sense that no strong earthquake of magnitude M>6.0 has occurred. This observation provides an important insight for the evolution of a suitable model for the long-term prediction of strong earthquakes in the Indian subcontinent and attendant seismic hazard assessment.

Rheology of the Deep Continental Structures:

The response of the lithosphere to external force depends on its rheology of different layers which, in turn, depends on geothermal gradient, crustal thickness and composition. These three parameters govern the level of stress and its distribution in the lithosphere. The stress in the lower lithosphere is dissipated by ductile creep and is eventually transferred to the upper part of the lithosphere (Reddi, 1995) who further identified that the stress amplification progresses with time.

In the ancient Indian shield, having witnessed many geothermal perterbations, earthquakes originate at any level in the whole crust or in the mantle below the Moho. Some of the earthquakes originated in different depth levels are shown in the Fig. 2 focal depths for the rest of the events are not available. Ramalingeswara Rao and Divakara Rao (1995) have observed that some of the significant earthquakes such as Coimbatore, 1900, (M=6.0, h=70 km), Satpura, 1938 (M=6.3, h=50 Km) and Shimoga, 1975 (M=5.0, h=35 kms) occurring at depths between 35 to 70 kms were not associated with foreshocks or aftershocks. They have termed these earthquakes as independent events. The absence of foreshocks and aftershocks may be because these events have occured in the corresponding layer of deep continental structures having homogeneities of the rock with uniform thickness either in lower crust or in the upper brittle mantle. According to Reddi (1995), the maximum compressive horizontal principal stress (MCHPS) build up in the upper brittle crust is generally associated with the high heat flow (HF) of the range of 70-110 mWm-2. As the HF increases from 70 to 110 mWm-2, the brittle upper crustal layer thins out rapidly resulting in a spectacular rise in stress level in this layer. In other words, HF tends to control the depth of the brittle ductile transition. The rheological heterogeneities in different geological settings are evident (Fig 3). We observe that all the cratons are showing low HF values whereas in the S - mobile belt, the Heat Flow (HF) values are high, e.g., Bundelkhand craton ( HF about 40 mwm-2) and Narmada-Tapti-Son Valley mobile belt (HF 70-110 mwm-2) respectively. As pointed out by Mahadevan (1995), the depth of creep in the central region could be around 55 km, in SONATA ( Son-Narmada-Tapti ) region and Western Peri-cratonic Belt of Active Rift System (BARS), where higher thermal gradients prevail, this depth may be even shallower and it would be muchdeeper in the southern part of the shield. The rheology of the continental crust was picturised by Molnar (1988), who conceived it simply as "Jam-Sandwich like". The strength of the material in crust is high or low at different depth levels concordant with temperature - depth profiles in the regimes. Temperature and mechanical strength profiles falling in the cratons such as Kolar, Karadikuttam and Singhbhum and in mobile belt such as Agnigundala, Jharia and Khetri have been observed to be rheologically different. In the mobile belts, the layer of low mechanical strength is thicker than in cratons. Presence of Rheological Waveguide in Peninsular India The above observations, based on the rheological model computations made by Manglik and Singh (1991, 1992) indicate the large thickness of the ductile layers in the S-mobile belts of South Indian shield (Fig.3). Significant difference in the mechanical strengths of the mobile belts with reference to cratons make them act as a Rheological (or stress) wave guide (Raval, 1990). According to Ramalingeswara Rao (1994b), the historical and recent earthquake data upto 1994 confines to the S-shape mobile belt and/or rheological (stress) - waveguide. The distributions of earthquakes in this belt shows a net like occurrence in 3-dimension mostly in brittle upper crust of the Indian Peninsular shield depending upon the localised stress amplification. According to Long (1976), the stress amplification is anomalous in rigid structures which need not necessarily be mafic units. They may have shape which allows amplification or concentration of regional stresses or change in stress, which may be related to differential block movement or plate movement and may trigger earthquakes. Gowd et al (1996) have computed the vertical gradient of (SHmax), Maximum Principal Stress and horizontal Compressive stress for the linear seismic belts (defined by them). The gradient is about 55 MPa/km which is amplified almost two times, when compared to the global average of 29 MPa/km. Some of their linear seismic belts are also parts of the S-shaped mobile belts of South India. All the above observations indicate that, in the context of motion of the Indian Plate, the intraplate deformation is taking place in the Indian Peninsular Shield. By using the emperical formulation of Gowd et al (1986, 89), the maximum horizontal principal compressive (MHPC) stresses have been computed for three sites 1) Kolar Gold Field (Champion Reef Mine), 2) Malanjkhand (Copper Mine), M.P. and 3) Sardar Sarovar project located in the mobile belt. The computed values of MHPC for the above three sites at 5 kms depth are 72.5 MPa (N50oE), 171.3 MPa (N70oE) and 350 MPa (N-S) respectively. These stresses computed from the In-situ stress experiment from Kolar, Mosabhani and Sardar Sarovar Dam indicate that Mosabani and Sardar Sarovar values are, respectivly approximately two fold and five fold as compared to Kolar. This clearly indicates northward enhancement of the stress with respect to distance from the southern most point i.e. Kolar. This implies northward decrease of thickness of the brittle crust all along the S-mobile belt as shown in Fig. 3. Five to six probable spatial seismic gaps with regard to earthquake of magnitude 3 and above since last two centuries have been observed in the Indian Peninsular Shield (Ramalingeswara Rao and Divakara Rao, 1995). Also Deccan Volcanic Province (DVP) and Western Ghats (WG) were quiescent for 70 years, during 1869-1937, and 95 years during 1855-1950 respectively. Whereas the mobile belt have been quiscent for shorter periods. These quiescent periods indicate the build up of stresses in the intra-cratonic regions to be slower than in the mobile belts of the Indian Shield (Ramalingeswara Rao 1994 a). The seismic gaps, quiescent periods and occurrence of large earthquake of magnitude M > 6.0 in the Peninsular Indian shield areas are indicative of the pattern of ongoing intraplate deformations. Ramalingeswara Rao (1996 ) have estimated the strain rates for different tectonic areas based on geological units of Radhakrishna and Naqvi (1986). The values are given in Table-1. The strain rates are maximum in NTSL (1.5x10-8/year) whereas the craton region these are low (5x10-13/year).

According to Majumdar and Biswas (1995)), in the Indian continental shield, a relatively higher seismicity is observed to the west of Calcutta, in the central part of the eastern coast of Peninsular India (i.e. in and around Godavari Rift) and in the southern part of Peninsular India. Thus, frequent occurrences of earthquakes provide evidence that intraplate deformation is in progress in this region.

Stresses in Indian Shield: An overall general feature of the principal compressive stresses on the Indian Peninsular Shield derived from the focal mechanism data, in-situ stress measurements and geodetic data is used by the several workers e.g. Chandra (1977), Ramalingeswara Rao (1987,92), Gowd et al (1990), Rajendran et al (1992) and Rastogi (1992). Weissel et al (1980) and Petroy and Weins (1989)observed the existence of N-S, NW-SE and E-W oriented compressive stresses throughout the Indo-Australian plate. They suggested that the pattern of SHmax in the plate interiors is strongly influenced by collision of the Indian plate with the Eurasian plate. Thrust faulting at shallow depths observed in Indian and Australian continental regions suggests existence of large horizontal stresses (Cloetingh and Wortel, 1986). Rajendran et al (1992) have given the generalized state of intraplate stress in the Peninsular India and Andaman and Nicobar Islands as a uniform maximum horizontal stress orientations which may vary from N-S to NNE-SSW. Ramalingeswara Rao (1992) had identified the intraplate stress of SHmax orientations predominently in three directions viz, NE-SW, N-S and NW-SE on the south of transition zone in the Indian shield. They deviate from their normal path north of low-to-high grade transition zone (TZ) arch region and at central Indian continental region (NTSL) particularly in Saurashtra-Calcutta arch. North of NTSL the orientation of SHmax is N70oE at Mosabanias as per In-situ stress measurements (Gowd et al 1992). Gowd et al (1992) evaluated tectonic stress field in the Indian sub-continent and prepared a map of maximum horizontal compressive stress orientations by using the orientations derived from borehole breakouts, hydraulic fracturing stress measurements and earthquake focal mechanisms. The mean orientation of SHmax in the mid-continent stress province which is seen as NTSL. is N23oE, subparallel to the direction of compression expected to arise from the net resistive forces at the Himalayan collision zone, suggesting that it is largely determined by the tectonic collision processes.

According to Ramaswamy (1988), in between Mangalore-Madras Arch and Saurashtra-Cuttack Arch, there is another arch, which is running from Belgaum to Kakinada. The above three Cymatogenic arches might have been formed due to northerly pushing/driving forces on the Indian plate. According to Ramalingeswara Rao (1996 b), these cymatogenic arches are being recognised by observation of historical occurrences of earthquakes in these areas of South Indian Shield. The altitudes of these arches gradually decrease from South to North whereas the level of seismicity increases in this direction. Fig. 4 shows the location of these 3 arches and S-shaped mobile belt. In addition to the S-shaped mobile belt, these arches are also controlling the seismicity - cutoff depths at different arches, viz., south of Mangalore-Madras low magnitude earthquakes of very shalloow 0-5 Km depth. North of Belgaum-Cuttack arch, the focal depths are of 10-15 km, with moderate magnitude ( 5.0) earthquakes. In Saurashtra-Cuttack Arch, focal depths are ranging from 15-45 Km and magnitude of earthquakes are upto 6.5 (Fig. 2). It indicates that active deformations might have taken place at these arches continuously or discontinuously. The stress variations may be due to various thicknesses of brittle or brittle-ductile layer in the upper mantle. According to Manglik and Singh (1991, 1992), the thickness of ductile layer increases northwards whereas the thickness of brittle crustal layer decreases, and the brittle upper mantle layer is rather thin under the Indian Shield. The large magnitude earthquakes (such as Coimbatore, Bellary, Satpura etc.) at relatively deeper depths are observed to be independent events. The earthquakes which are occurring in the brittle upper crustal layer are followed by Foreshock - Aftershock sequences.

Thus, geodynamically, Indian shield is undergoing deformations due to different driving forces, and thereby the different seismicities in different areas have been observed. The three major geodynamically disturbed regions are i) Low-to High-Grade Transition Zone (TZ), where the large crustal shortening and/or thickening had taken place (Ramalingeswara Rao, 1992, Condie et al, 1982) ii) Narmada-Sone Lineament (NSL): Geochemical and geological evidences suggests the occurrence of an early proterozoic ocean in central India located between Dharwar Craton, Singhbhum-Marwar proto continent in the South and Bundelkhand protocontinent in the North. During middle proterozoic, the oceanic lithosphere subducted towards south along the northern margin of Southern protocontinent (Raza et al, 1993). iii) the Belgaum-Kakinada arch, which is also seismically active during 1965-1996 for magnitude M > 5.0. This upwarp region is also identified by Rantsman et al (1994) in the morphostructural zoning of Himalayan belt, fordeep and the Indian shield.

Velocity Structure

Several authors have determined velocity structures in different parts of the Indian Shield based on either control source seismic data or surface wave dispersion data or P and S wave spectra or P wave tomography.

Singh and Rastogi (1978) have estimated the crustal structure beneath Hyderabad using the crustal transfer function of P waves of thirteen teleseismic earthquakes recorded at Hyderabad (HYB) seismograph station. The crust beneath Hyderabad is found to consist of three layers with total thickness of 36 Km. The thickness of top, middle and bottom layers are 21 Km, 8 Km, and 7 Km with P-wave velocity of 5.81, 6.41 and 6.66 km/sec, respectively. Singh (1982) has used the P and S waves spectra of three deep focus earthquakes recorded at Hyderabad seismograph station and determined the upper mantle velocity structure beneath Hyderabad. The upper mantle velocity structure beneath Hyderabad shows a low velocity zone of about 50 km thickness centered at a depth of about 95 km. Singh (1987) has determined the phase and group velocity across different paths of central India and estimated the average crustal thickness of 44 km. A low-velocity zone Vp=8.4 km/sec, Vs= 4.15 km/sec) is found from 100 km below the surface. Singh (1991) has used the fundamental mode Love and Rayleigh waves generated by earthquakes and determined the Q-structure beneath central India and found a high attenuation zone below a depth of 100 km.

Using the technique of tomographic inversion of teleseismic travel times, Rai et al 1992 have reported crustal thicknesses and velocity in some parts of the Indian shield. According to them crustal thicknesses vary between 34 to 39 km and velocities from 6.0 to 6.6 km/sec beneath south India. Anamalous low velocity crust (6.0 to 6.2 km/sec) characterises the northwest and southwest of the Deccan volcanic province. Table 1: Maximum Magnitude and Strain rate per year for different seismo- tectonic units of Indian Shield

_________________________________________________________________ Seismo-tectonic Maximum Mag. Strain rate Unit per year _________________________________________________________________ 1. Bundelkhand Craton 5.5 5.0x10-13 2. Western Dharwar Craton a) Without Koyna events 6.3 4.4x10-10 b) With Koyna events 6.3 6.13x10-10 (more than 80,000 events for 30 years) 3. Eastern Dharwar Craton 5.7 1.3x10-10 a) Cuddapah basin 3.5 1.2x10-10 b) Godavari Graben 5.7 2.2x10-10 c) Damodar Mahanadi Rift 5.7 2.0x10-9 4. Southern Granulite Terrain 6.0 2.4x10-10 5. S-Mobile belt 6.5 4.5x10-10 a) Transition Zone 5.0 3.3x10-10 b) Eastern Ghats 5.7 8.0x10-10 c) Narmada-Sone 6.5 1.57x10-8 d) Aravali 6.0 1.29x10-9 6. Koyna Region 6.2 1.3x10-7 _________________________________________________________________ References:

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It is an important to note that some of the significant earthquake in Indian subcontinent is unique and laying foundation for new investigations. For example, 1819 Kutch earthquake which had shown the first rupture on the surface of the earth, 1897, the great Assam earthquake is an instrumental in seismology to identify the P, S and Rayleigh waves and also the first acceleration estimation is made. In order to give more information, each earthquake event is specially studied and give their significance in seismological studies. Some more significant earthquake events beyond 1963AD are also noted such as Son-Valley earthquake during which the line of fire along a fault zone in which all the trees in a line were burnt ( Indra Mohan - personal Communication), Nepal-Bihar earthquake of 1934 had given an opportunity to study on ‘ liquefaction’ of the the sand in the river beds/ fault zones, while 15 August, 1950 earthquake had given an opportunity to study on the ‘land slides’. Koyna earthquake on the 10th December, 1967 had initiated to postulate the ‘Reservoir Induced Seismicity, RIS’ theory in India. The recent Killari earthquake of 30th September, 1993, is also significant earthquake because of its occurrence in Stable Cratonic region and hence it can be called as Cratonic Earthquake. Last but not the least, Jabalpur earthquake occurred on 21 May, 1997 in the central Indian rift system at a depth of 36 Km, is indicating the presence of rift pillows.

Some of the undocumented events as well unknown locations are studied individually and presented in the seismicity maps of the Indian continent. For easy access to identify the main source of the earthquake event, the author has given the bibliography of the Indian earthquakes and related important earthquake studies for the period of 1763- 1999. References:

1. Arora, S. K., G. J. Nair and T. G. Varghese, (1970) . Broach earthquake of March 23, 1970, Earthquake Notes, 42, 17-26.

2.Arora, S. K., K. R. Subba Rama, S. V. N. Murthy and M. K. Bhat, (1973) Recent Mandya earthquakes and aftershocks, micro seismic activity, Indian Jour. Met. & Geophys., 24, 375-382.

3. Athavale, R. N. (1995). Two Undocumented historic earthquakes and additional information on the major earthquake if September 1803 from north India. Curr. Sci. 69, No.3, 279-280.

4. Ambrasseys, N., larsen, G. and Moinfar, (1975). The Pattan earthquake of 28 Dec 1974. UNESCO, Paris (serial No: FMR/ Sc/ GEO/ 75/134), 1-44.

5. Ballalasen (1000AD). Adbutasagara , (Sanskrit text), Benaras, 1905.

6. Basu, K. L., (1964). A note on the Coimbatore earthquake of 8th February, 1900, Indian Jour. Met. & Geophys. , 15, 281-286.

7. Bath, M and Duda, S.(1979). Some aspects of Global Seismicity. Report No:1-79, Seismological Institute, Uppsal, Sweden p. 41.

8. Bapat, A., Kulkarni and Guha, S.K., (1983). Catalogue of earthquakes in Indian and neighbourhood from historic times upto 1979, Indian Society of Earthquake Technology, Roorkee, 1983.

9. Banerji, S. K, (1957). Earthquakes in Himalayan Region, Indian Association for the cultivation of Science, Calcutta, 1-64

10. Baird-Smith, R., (1843). Historical summary of Indian earthquakes with some remarks on the general distribution of forces throughout India and its frontier countries, Mem. on Earthq. Jour. Asiatic Society of Bengal, 12, 1029-1056.

11.Baird-Smith, R., (1844) Memoirs. on Indian Earthquakes, 1844, Jour. Asiatic Soc. Bengal, 152, 13(2), 964-983.

12. Bhan, S. N., (1955). Felt earthquakes in Srinagar, Indian Jour. Met. & Geophys. 6, 197

13. Bellamy, E. F. (1936). Index catalogue of epicenters for 1913-1930. The County Press, New Port, 1-33.(ISS).

14. Bellamy, E.F. (1947). Index catalogue of epicenter for 1931-35, The County Press, New Port, 1-20, (ISS).

15. Brijesh K, Bansal and Sushil Gupta, (1998). A glance through the seismicity of Peninsular India, Jour. Geol. Soc. India, 52, 1, 67-80.

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Earthquake History:
Historically Orissa has experienced very few moderate to large earthquakes. Some events with magnitudes in excess of 5.0 have originated in the Bay of Bengal off the coast of the state. Several faults have been identified in the region and some (4) have shown evidence of movement during the Holocene epoch. The Brahmani Fault (4) in the vicinity of Bonaigarh is among then. The Mahanadi also flows through a graben structure. Several deep-seated faults (4) are situated beneath the Mahanadi Delta. However, it must be stated that proximity to faults does not necessarily translate into a higher hazard as compared to areas located further away, as damage from earthquakes depends on numerous factors such as subsurface geology as well as adherence to the building codes.

Largest Instrumented Earthquake in Orissa
08 May 1963 - Bijakuli-Banei area, Orissa, Mb 5.2 (4)21.700 N, 84.900 E, D=033.0 kms, OT=14:15:03 UTC (4)This area is located to the east of Sambalpur. A higher magnitude of 6.0 is often listed for this event (14).

Seismic Hazard:-
The seismic hazard map of India was updated in 2000 (8) by the Bureau of Indian Standards (BIS). There are no major changes in the zones in Orissa with the exception of the merging of Zones I and II in the 1984 BIS map. Districts that lie in the Mahanadi river valley lie in Zone III, and within Orissa this zone stretches from Jharsuguda along the border with Chhatisgarh in a south-easterly direction towards the urban centres of Bhubaneswar and Cuttack on the Mahanadi Delta. The maximum intensity expected in these areas would be around MSK VII. Districts in the north and south-west of the state lie in Zone II.
In 1999, the Global Seismic Hazard Assessment Programme (GSHAP) published a map (6) displaying areas that could expect to have a peak ground acceleration (PGA) with a 10% probability of exceedance in 50 years. According to this map, parts of the state of Orissa along the Jharkhand border and along the Andhra-Chhatisgarh border can expect a PGA value in the range of 0.04g to 0.06g. A sliver of Balasore district in north-eastern Orissa, along the border with West Bengal can also expect similar values of PGA. Other sections of the state can expect values lower than 0.02g.
It must be noted that both, BIS and GSHAP estimate the hazard, based in part, on previous known earthquakes. Since the earthquake database in India is still incomplete, especially with regards to earthquakes prior to the historical period (before 1800 A.D.), these zones offer a rough guide of the earthquake hazard in any particular region and need to be regularly updated.
Significant Earthquakes in Orissa:-
The following list briefly outlines known earthquakes in this region which either had observed intensities of V or higher (historical events) or had known magnitudes of 4.5 or more (instrumented events). General locations are provided for historical events for which "generalized" epicentral co-ordinates are available. Some events which were significant for other reasons are also included. This list will be updated whenever newer information is available. Please note that Magnitude and Intensity are NOT THE SAME. All events are within the state or union territory covered on this page unless stated otherwise.
Acronyms Used:
D=Depth, OT=Origin Time, Mw=Moment Magnitude, Ms=Surface Wave magnitude, Mb=Body Wave Magnitude, ML=Local Magnitude, MT=Magnitude Type unknown.

26 August 1676 - Balasore area, Orissa.Maximum observed intensity IV (16). Felt distinctly (16) in the town as well as on ships in the harbour at around five in the morning local time. A uniform time was not implemented in India until 1905, so do not convert the above stated time into Indian Standard Time.
15 June 1837 - Rambha-Paluru area, Orissa.19.500 N, 85.100 E (13)Maximum observed intensity VI (13). This area is located on the southern shore of the Chilka Lake, to the north-east Behrampur.
16 March 1858 - Baleshwar-Chandipur area, Orissa.21.500 N, 87.000 E (3)Maximum observed intensity V (3).
25 February 1860 - Karantola area, Orissa.19.400 N, 84.900 E (13)Maximum observed intensity V (13). This area is located to the north-east of Behrampur.
17 June 1891 - Near Palmyras Point, Orissa.20.800 N, 87.000 E (3)Maximum observed intensity V (3). This area is located east of Dhamara at the mouth of the Brahmani River.
12 June 1897 - Near Rangjoli, Assam, Mw 8.1 (2)26.000 N, 91.000 EThis is the most powerful intraplate earthquakes in the Indian sub-continent. Close to 1,500 people were killed in Assam, Meghalaya and adjoining parts of the Bengal. Tremors were felt strongly at Balasore in Orissa (11).
22 June 1897 - Karantola area, Orissa, M? 5.5 (13).19.400 N, 84.900 E (13)Maximum observed intensity VII (13). This area is located to the north-east of Behrampur.
04 April 1905 - Kangra, Himachal Pradesh, Mw 7.8 (1)32.300 N, 76.300 E, OT=00:50 UTC (1) This is the deadliest earthquake in modern Indian history. Close to 19,800 people were killed and thousands were injured in the Kangra area. Tremors felt (10) all over the Indian subcontinent, including in Orissa, at Balasore, Cuttack and Jobra.
15 January 1934 - Indo-Nepal Border region, Mw 8.0 (12)26.500 N, 86.500 E, OT=08:43:25 UTC (4) Close to 10,700 people killed in North Bihar and Nepal. Heavy damage in the towns of Muzaffarpur, Motihari, Dharbhanga, and Munger (Monghyr). Tremors felt (5) all over the Indian subcontinent, including many places in Orissa, including Balasore, Cuttack and Puri.
26 June 1941 - Andaman Islands, India, Mw 7.7 (12).12.500 N, 92.500 E, OT=11:52:03 UTC (12)Shaking from this earthquake was experienced along the east coast of India, and also in the city of Cuttack in Orissa.
08 May 1963 - Bijakuli-Banei area, Orissa, Mb 5.2 (4)21.700 N, 84.900 E, D=033.0 kms, OT=14:15:03 UTC (4)This area is located to the east of Sambalpur. A higher magnitude of 6.0 is often listed for this event (14).
15 April 1964 - Sagar Island, West Bengal, Mb 5.2 (4)21.700 N, 88.070 E, D=036.0 kms, OT=16:35:53 UTC (4) It was felt the strongest in Orissa's Balasore area, with an MM intensity of VII (9). This quake caused damage in southern parts of West Bengal and even in the city of Kolkata. In Kolkata it reached a maximum MM intensity of V.

05 August 1979 - Dublabera-Majhgaon area, Jharkhand, Mb 4.7 (4).22.100 N, 84.900 E, OT=01:18:37 UTC (4)This event is located along the state border between Jharkhand and Orissa, near the town of Daspur in north-eastern Orissa.

08 April 1982 - Bay of Bengal, Mw 5.2 (17).18.510 N, 86.310 E, D=024.0 kms, OT=02:41:16 UTC (4)This event was centred in the Bay of Bengal. The epicentre was located roughly 150 kilometres south of Puri, Orissa and 188 kms east of Baruva, Andhra Pradesh.14 October 1982 - Khajuripada-Banigochha area, Orissa, Mb 4.7 (4).20.390 N, 84.420 E, OT=12:56:09 UTC (4)This area is located about 140 kilometres to the west of Bhubaneswar.

01 July 1985- Bay of Bengal, Mw 5.4 (17)18.367 N, 87.188 E, D=010.0 kms, OT=02:23:52 UTC (15)This event was centred in the Bay of Bengal. The epicentre was located roughly 214 kilometres south-east of Puri, Orissa and 280 kms east of Baruva, Andhra Pradesh.

27 March 1995 - Laimura-Deogarh area, Orissa, Mb 4.6 (15)21.671 N, 84.565 E, D=010.0 kms, OT=07:52:10.60 UTC (15)This area is located to the east of Sambalpur. This earthquake is called the Bonaigarh earthquake (4). A maximum MSK intensity (4) of V was observed. Many buildings were damaged (4) at Bonaigarh and Deogarh.

21 June 1995 - Kasijodi-Nuakot area, Orissa, Mb 4.7 (15)21.780 N, 85.327 E, D=033.0 kms, OT=18:35:41.23 UTC (15)This area is located to the north-west of Keonjhargarh and to the south-east of Rourkela.

22 May 1997 - Jabalpur-Kosamghat, Madhya Pradesh, Mw 5.8 (15)23.083 N, 80.041 E, D=036.0 kms, OT= 22:51:28.7 UTC (15) 38 people were killed, and more than a thousand were hurt in the city of Jabalpur and the surrounding areas. Tremors from this earthquake were felt (MM IV) at Rourkela and Sambalpur in western Orissa.

12 June 2001 - Konokjora-Sundargarh area, Orissa, Mw 4.7 (7)22.223 N, 83.948 E, D=033.0 kms, OT=12:41:01 UTC (15)This area is located to the north of Sambalpur along the border with the neighbouring state of Chhatisgarh. The shock was felt for a few seconds (MM IV) in the districts of Deogarh, Jharsuguda, Sambalpur, Sundargarh and Rourkela in Orissa and at Jashpur and Raigarh in Chhatisgarh.

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Author: Ramalingeswara Rao B.

Source: Journal of Seismology, July 2000, vol. 4, no. 3, pp. 247-258(12)

Publisher: Kluwer Academic Publishers

Abstract:

Seismic strain rates for the entire Indian Peninsular Shield are estimated from the available historical and recently observed seismicity data from the last 199 years (1800–1998). Typical strain rates ranging from 10^-13 to 10^-8 per year have been calculated for different regions of Peninsular India by using Anderson's (1979) method and analysis. A correlation between the seismically deforming zones and high heat flow areas has been observed. The deformation zones are divided into two classes, with low and high deformation zones of Cratons and Mobile belts with further sub-divisions. Seismo-tectonics of the Southern Peninsular India is also discussed in the light of recent occurrence of the disastrous earthquakes of Killari (September 29, 1993) and Jabalpur (May 21, 1997).

S.No	Max. Magnitude	Seismotectonic Units	Strain Rate ranges
1	5.5	Bundelkhand Craton,BKC	(5.0-5.4)10^-13
2		Western Dharwar Craton(WDC)
a	6.3	Without Koyna 1lac events(DC)	(4.0-6.1)10^-10
b	6.3	With Koyna events(WDC)	(6.1-8.2)10^-10
3		Eastern Dharwar Craton(EDC)
a	5.7	Godavari Graben	(1.4-2.2)10^-10
b	5.7	Damodar-mahanadi Rift	(2.0-3.0)10^-9
c	3.5	Cuddapha basin	(1.2-1.4)10^-10
4	6.0	Southern Granulite Terrain	(2.4-4.6)10^-10
5		S-Mobile belt
a	5.0	Transition Zone	(3.3-6.5)10^-10
b	5.7	Eastern Ghats	(8.0-11.0)10^-10
c	6.5	Son-Narmda Rift	(1.5-1.6)10^-8
d	6.0	Aravalli	(1.29-1.85)10^-9
6	6.2	Koyna Region	(1.3-1.8)10^-7
7	6.5	Penisular India	(6.0-6.2)10^-10