Earthquakes in the Andaman & Nicobar Islands, India

State - Andaman & Nicobar Isls. (U.T.)
Capital - Port Blair
Population - 356,152 (2001)

Population per tehsil (Andaman Islands)
Port Blair - pop. 159,845
Ferragunj - pop. 48,628
Diglipur - pop. 42,877
Rangat - pop. 38,324
Mayabander - pop. 23,912

Population per tehsil (Nicobar Islands)
Nancowry - pop. 21,776
Car Nicobar - pop. 20,292

Earthquake History
The map to the left shows all historically recorded earthquakes in the Andaman & Nicobar Islands. Earthquakes having magnitudes greater than 4.0 since 1973 are also shown. Two prominent red triangles visible to the north-east of Port Blair, i.e. in the top half of the map, are the only volcanoes in India. The northernmost of the two is the Barren Island Volcano. This volcano has erupted in recent times. The other volcano is called Narcondam and is dormant. The Andaman and Nicobar Islands are located near the boundary of the Indian plate and the Burmese Microplate. The Andaman Trench marks this boundary and lies in the Bay of Bengal to the west of the archipelago. Another prominent feature is the north-south West Andaman fault which is strike-slip in nature and lies in the Andaman Sea, to the east of this island chain. The Andaman Sea, just like the Atlantic Ocean, is presently being widened by a tectonic process called "Sea Floor spreading". This is taking place along undersea ridges on the seafloor. The Indian plate is diving beneath the Burmese Microplate along the Andaman Trench in a process known as "Subduction". Shallow and occasional intermediate-depth earthquakes delineate the subducted slab under the Andaman-Nicobar islands joining the seismicity trend of the Indo-Burman ranges. 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

All of the Andaman & Nicobar Islands lie in Zone V. The entire island chain is also susceptible to tsunamis both from large local quakes and also from massive distant shocks. No warning system is presently in place for any of the islands in this chain.  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 the Andaman Islands & the Nicobar Islands).
 

Largest Instrumented Earthquake in the Andaman & Nicobar Islands
26 December 2004 - Sumatra-Andaman Earthquake, Mw 9.1
03.298 N, 95.778 E, D=010.0 kms, OT=00:58:50 UTC
A "very great" earthquake struck the North Indian Ocean & the Bay of Bengal at 00:58 UTC on 26 December 2004. 2,30,210 people were are estimated to have been killed in the Indian Ocean-wide tsunami generated by this earthquake. The Nicobar Islands, and to a lesser extent the Andaman Islands, were hardest hit territory in India with as many as 4,486 deaths. Extensive damage occurred in the Nicobar Islands due to the tsunami that is estimated to have attained heights of as much as 20-metres at places.

Significant Earthquakes in the Andaman & Nicobar Islands
The following list briefly outlines known earthquakes in this region. 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

31 December 1881 - NNW of the Andaman Islands, India, Mw 7.9 (Bilham et al 2000)
No recording stations were present at the time, though calculations were made by various agencies of the seismic vertical from the time of the shock recorded at different locations including Kolkata (formerly Calcutta), Vishakhapatnam, Chennai and Port Blair. They also recorded the arrivals of tsunamis at different points on the eastern coast of India. The tsunami had a maximum run-up of 1.2 meters on the Coromandel coast. Damage occurred to masonry buildings at Port Blair.

16 November 1914 - South-west of Barren Island, India, Ms 7.2,
16:17:06.0 UTC, 12.00 N, 94.00 E

28 June 1925 - SE of Little Andaman Island, India
13:41:35.0 UTC, 10.20 N, 92.80 E

1 August 1929 - Andaman Sea, ESE of Barren Island, India, Ms 6.5
05:01:48.0 UTC, 12.00 N, 95.50 E

9 December 1929 - SSE of Great Nicobar, India, Ms 6.7, Mb 7.2
06:49:54.0 UTC, 04.50 N, 94.50 E

19 March 1936 - Little Andaman Island, India, Ms 6.5
09:04:05.0 UTC, 10.50 N, 92.50 E

14 September 1939 - Andaman Sea, SE of Barren Island, India, Ms 6.0
09:00:58.0 UTC, 11.50 N, 95.00 E

26 June 1941 - West of Middle Andaman Island, India, Mw 7.7
11:52:03 UTC, 12.50 N, 92.50 E
This is strongest earthquake on record in this region to be recorded instrumentally. It caused damage in the Andaman Islands, including at Port Blair, destroying many of its major buildings. The quake also spawned a tsunami in the Bay of Bengal which was recorded along the Coromandel Coast.

8 August 1945 - North of Little Andaman Island, India, Ms 6.7
09:53:40.0 UTC, 11.00 N, 92.50 E

17 May 1955 - Off the east coast of Great Nicobar Island, India, Mw 7.0, Ms 7.2
14:49:49 UTC, 07.00N, 94.00E

18 June 1957 - Andaman Sea, ENE of Narcondam Island, India, Ms 6.5
14:48:17.0 UTC, 14.00 N, 96.00 E

14 February 1967 - Andaman Sea, West of the Mergui Archipelago, M? 6.8
01:36:04 UTC, 13.70N, 96.50E

20 January 1982 - 8.5 kilometers east of Bananga, Great Nicobar Island, Mw 6.2
04:25:11 UTC, 06.95N, 94.00E
Followed by a Mw 6.1 quake at 07:09:17 UTC which had its epicentre 8 kilometers south-east of Laful, Great Nicobar Island. Some injuries and considerably damage occurred in the Nicobar Islands due to both these quakes.

20 January 1982 - 8 kilometers south-east of Laful, Great Nicobar Island, Mw 6.1
07:09:17 UTC, 07.12N, 93.94E
Followed the Mw 6.2 quake at 04:25:11 UTC which had its epicentre 8.5 kilometers east of Bananga, Great Nicobar Island. Some injuries and considerably damage occurred in the Nicobar Islands due to both these quakes.

13 August 2002 - Diglipur (North Andaman), India, Mw 6.5
13.005 N, 93.105 E, D=21.0 kms, OT=22:28:29 UTC
A strong earthquake struck northern parts of the Andaman Islands in the Andaman & Nicobar Archipelago, on 14 August 2002 at 03:58 AM local time. It had a magnitude of Mw=6.5 and is thought to have lasted close to 2-minutes. Several moderate aftershocks were felt in the region in the following days including two large events on the 14th and 18th of September 2002. The mainshock is believed to have generated a local tsunami in the Andaman Sea.

26 December 2004 - Sumatra-Andaman Earthquake, Mw 9.1
03.298 N, 95.778 E, D=010.0 kms, OT=00:58:50 UTC
A "very great" earthquake struck the North Indian Ocean & the Bay of Bengal at 00:58 UTC on 26 December 2004. 2,30,210 people were are estimated to have been killed in the Indian Ocean-wide tsunami generated by this earthquake. The Nicobar Islands, and to a lesser extent the Andaman Islands, were hardest hit territory in India with as many as 4,486 deaths. Extensive damage occurred in the Nicobar Islands due to the tsunami that is estimated to have attained heights of as much as 20-metres at places.

26 December 2004 - Off Pulo Kunji (Sumatra-Andaman) Aftershock, Mw 7.2
06.910 N, 92.960 E, D=039.0 kms, OT=04:21:29 UTC
A major earthquake struck the Nicobar Islands to the west of Pulo Kunji on Great Nicobar Island, on 26 December 2004 at 09:51 AM local time. It had a magnitude of Mw=7.2 and was one the strongest aftershocks within 24-hours of the Sumatra-Andaman earthquake.

24 January 2005 - Off Miroe Island (Sumatra-Andaman) Aftershock, Mw 6.3
07.375 N, 93.453 E, D=025.0 kms, OT=04:16:48 UTC
A strong earthquake struck the Nicobar Islands on 24 January 2005. It had a magnitude of Mw=6.3 and was felt in the Nicobar Islands and in adjoining parts of Sumatra. This earthquake is an aftershock to the Sumatra-Andaman earthquake on 26 December 2004.

24 July 2005 - Off Teresa Island, Nicobar Islands, Mw 7.3
07.926 N, 92.146 E, D=016.0 kms, OT=15:42:05 UTC
A major earthquake struck the Nicobar Islands near Teresa Island, on 24 July 2005 at 21:12 PM local time. It was felt in many parts of the Andaman & Nicobar Archipelago and in parts of peninsula India. It had a magnitude of Mw=7.3 and did not result in a tsunami in the Bay of Bengal.

23 December 2006 - Koname, Little Andaman Island, Mw 6.3
10.681 N, 92.390 E, D=017.0 kms, OT=19:50:47 UTC
A strong earthquake struck the island of Little Andaman on 23 December 2006 at 01:20 AM local time. The earthquake had a magnitude of Mw=6.3 and was felt in some parts of the southern Andaman Islands including Port Blair.

8 January 2007 - Off Kalara, Teresa Island, Mw 6.1
08.109 N, 92.553 E, D=032.7 kms, OT=12:48:44 UTC
A strong earthquake occurred in the Bay of Bengal off the coast of Teresa Island in the Nicobar Islands on 8 January 2007 at 18:18 local time. The earthquake had a magnitude of Mw=6.1.

26 July 2007 - Off Cape Edinburgh, Little Nicobar Island, Mw 6.1
07.084 N, 92.588 E, D=05.0 kms, OT=23:37:32 UTC
A strong earthquake occurred in the Bay of Bengal off Cape Edinburgh on the west coast of Little Nicobar Island, on 26 July 2007 at 05:07 local time. The earthquake had a magnitude of Mw=6.1.