Earthquakes in Bihar, India

State - Bihar, India
Capital - Patna
Population - 82,878,796 (2001)

Million+ Cities
Patna - pop. 1,707,429

Population per district (Top 5)
Patna (district) - pop. 4,718,592
Purba Champaran - pop. 3,939,773
Muzaffarpur - pop. 3,746,714
Madhubani - pop. 3,575,281
Samastipur - pop. 3,394,793

Earthquake History
The state of Bihar lies in the Gangetic Plain. This is a fore-deep, a downwarp of the Himalayan foreland, of variable depth, converted into flat plains by long-vigorous sedimentation. This is known as a geosyncline and the Gangetic Plain is the Indo-Gangetic Geosyncline. This has shown considerable amounts of flexure and dislocation at the northern end and is bounded on the north by the Himalayan Frontal Thrust. The floor of the Gangetic trough (if see without all the sediments) is not an even plain (5), but shows corrugated inequalities and buried ridges (shelf faults). Western Bihar sits on the sub-surface Faizabad ridge while the eastern sections sit on the Munger-Saharsa Ridge. the areas near the border with West Bengal lie on the Kosi Graben (Purnea-Kasganj Graben). The central sections of Bihar lie (5) atop the Gandak depression and East Uttar Pradesh shelf. The Himalayan Frontal Thrust does not run in Bihar, though, it runs across the border in Nepal. Several faults have been identified in the region and some (1) have shown evidence of movement during the Holocene epoch. The West Patna Fault runs in a NE-SW direction from near Arrah in the south to the Nepalese border near Madhubani in the north. Running almost parallel to it is the East Patna Fault which extends from the south-east of Patna in the south to the Nepalese border to the east of Madhubani. Another fault, this one also lying parallel to the previous two, is the Munger-Saharsa Ridge Fault which runs from Biharsharif to near Morang in eastern Nepal. Apart from these there are east-west running tear faults in the region that control (5) the courses of the main rivers. 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.

Seismic Hazard

The seismic hazard map of India was updated in 2000 (4) by the Bureau of Indian Standards (BIS). There are no major changes in the zones in Bihar. Districts such as Araria, Darbhanga, Madhubani, Sitamarhi and Supaul lie in Zone V. The south-western districts of Aurangabad, Bhojpur, Buxar, Gaya, Jahanabad, Kaimur, Nawada and Rohtas lie in Zone III. The remaining districts of Bihar, including the capital city of Patna lie in Zone IV. 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 (See also: GSHAP Hazard Map for Bihar).

Largest Instrumented Earthquake in Bihar
15 January 1934 -  Bihar-Nepal border, Mw 8.0 (7).
26.500 N, 86.500 E, OT=08:43:25 UTC
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 all over the Indian subcontinent, as far as Mumbai and even Kerala.

Significant Earthquakes in Bihar
The following list briefly outlines known earthquakes in this region which either had observed intensities of VI or higher (historical events) or had known magnitudes of 5.0 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, M?=Magnitude Type unknown

26 August 1833 -  Eastern Nepal, Mw 7.9 ±0.1 (13).
27.500 N, 86.500 E (10)
Nearly 500 people were killed, most of the fatalities in the Kathmandu valley. Strong shaking caused damage at many places in Bihar like Bhagalpur and Munger. Tremors were felt as far as Kolkata and Jabalpur.

04 October 1833 - Nepal-India border region.
27.000 N, 85.000 E (10)
Felt over a wide area of northern and eastern India.

18 October 1833 - Nepal-India border region.
27.000 N, 85.000 E (10)
Additional damage and casualties in Nepal and Bihar. Felt over a wide area of northern and eastern India.

21 May 1842 - Banka-Dhuraia area, Bihar.
25.000 N, 87.000 E (10)
Maximum observed intensity VII (10).

11 November 1842 - Bihar-Bengal area.
27.000 N, 88.300 E (10)
Maximum observed intensity IX (10). Damage (11) at Munger, Bihar. Felt (10) at Kolkata, Darjeeling and Guwahati. Seiches (12) observed in the northern Bay of Bengal.

23 May 1866 - Nepal-India border region.
27.700 N, 85.300 E (10)
Maximum intensity VIII (10) at Kathmandu and in Bihar, India.

07 October 1920 - Jahanabad-Sasaram area, Bihar.
25.000 N, 83.800 E (14)
Maximum observed intensity VII (14).

02 June 1927 - Umaria area, Madhya Pradesh, Mw 6.4 (3)
23.500 N, 81.000 E, 16:37:34 UTC (1)
This earthquake was located in Madhya Pradesh's Umaria District. It was a deep-seated event and was felt (10) as far as Allahabad in Uttar Pradesh and Dehri-on-Son in Bihar.

15 January 1934 -  Bihar-Nepal border, Mw 8.0 (7).
26.500 N, 86.500 E, OT=08:43:25 UTC
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 all over the Indian subcontinent, as far as Mumbai and even Kerala.

17 February 1985 - Rajauli area, Bihar, Mb 4.7 (1).
24.670 N, 85.480 E, OT=23:06:55 UTC (1)
This event is located along the state border between Jharkhand and Bihar, near the town of Rajauli in southern Bihar.

20 August 1988 - Udaypur Gahri, Nepal, Mw 6.8 (9).
26.755 N, 86.616 E, D=057.0kms, OT=23:09:09 UTC (9)
Nearly 900 people were killed in eastern Nepal and the bordering district of Bihar, India. Damage was also reported from Kathmandu and Sikkim. It was felt over much of northern and eastern India and much of Nepal and as far as New Delhi.

15 February 1993 -  Qasba-Purnea area, Bihar, Mb 4.9 (1).
25.980 N, 87.510 E, D=025.0 kms, OT=14:29:41 UTC (1)
- No Comment -

References
01) Dasgupta, S., Pande, P., Ganguly, D., Iqbal, Z, Sanyal, K, Venkatraman, N.V., Dasgupta, S., Sural, B., Harendranath, L., Mazumdar, K., Sanyal, S., Roy, K., Das, L.K., Misra, P.S., Gupta, H.,  "Seismotectonic Atlas of India and its Environs", Geological Survey of India, 2000.

02) Giardini, D., Grünthal, G., Shedlock, K.M., Zhang, P., "The GSHAP Global Seismic Hazard Map", Annali di Geofisica, Vol. 42, No.6, p. 1225 - 1230, 1999.

03) Johnston, A.C., Report TR-102261, Electric Power Research Institute, Chap.3, 1993.

04) IS 1893 (Part 1): 2002 Indian Standard Criteria for Earthquake Resistant Design of Structures Part 1 General Provisions and Buildings (Fifth Revision).

05) Mathur, S.M., "Physical Geology of India", National Book Trust of India, 1998.

06) Tandon, A.N., and Srivastava, H.N., "Earthquake occurrence in India: Earthquake Engineering (Jai Krishna Vol.)", pp. 1 - 48, Sarita Prakashan, Meerut, 1974.

07) Pacheco, Javier F., and Sykes, Lynn R., "Seismic moment catalog of large shallow earthquakes, 1900 to 1989", Bulletin of the Seismological Society of America, v. 82, no. 3, p. 1306 - 1349, 1992.

08) Wessel, P., and Smith, W.H.F., "Free software helps map and display data", EOS Trans., AGU, 1991, 72, 441, 445.

09) U.S. Geological Survey, National Earthquake Information Center, Golden, CO, USA.

10) Chandra, U., "Earthquakes of Peninsular India--A seismotectonic study", Bulletin of the Seismological Society of America, Vol. 67, No. 5, pp. 1387 - 1413, 1977.

11) Memoirs of the Geological Survey of India, Vol.73, pp. 100-101, Kolkata, 1939 (1981 Reprint).

12) Berninghausen, W. H., "Tsunamis and Seismic Seiches reported from regions adjacent to the Indian Ocean", Bulletin of the Seismological Society of America, Vol. 56, No.1, p 69 - 74, 1966.

13) Bilham, R, "Location and Magnitude of the 1833 Nepal earthquake and its relation to the rupture zones of contiguous Great Himalayan earthquakes", Current Science, 69 (2), 155-187, 25 July 1995.

14) International Seismological Summary