Earthquakes in Sikkim, India

State - Sikkim, India
Capital - Gangtok
Population - 540,493 (2001)

Population per district (Largest)
East - pop. 244,790

Earthquake History
The earthquake activity in this region is due to the Indian plate diving (thrusting) beneath the Eurasian plate. The state is mainly mountainous and underlain by several thrust faults. Most significant are the Main Boundary Thrust (MBT), the Main Central Thrust (MCT) and the Himalayan Frontal Thrust (HFF).

Seismic Hazard

All districts of the state of Sikkim 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 Sikkim).

Largest Instrumented Earthquake in Sikkim
19 November 1980 - Near Gangtok (Sikkim-West Bengal Border region), 6.1 Ms (PAS)
19:00:46.9 UTC, 27.39N, 88.75E, 17 kms depth
Eight people were injured in Gangtok and there was also minor damage reported from the city. the quake was felt in eastern and north-eastern India, Bangladesh, Bhutan and Nepal.

Significant Earthquakes in Sikkim
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

15 January 1934 - Indo-Nepal Border region, Mw 8.0
14:21:25 IST / 08:43:25 UTC, 26.50N, 86.50E
Nearly 10,500 people were killed in Bihar and Nepal. Damage was also reported from many towns in Sikkim.

12 January 1965 - West of Gangtok (Indo-Nepal Border region), 6.1 (TS)
13:32:24 UTC, 27.60N, 88.00E

19 November 1980 - Near Gangtok (Sikkim-West Bengal Border region), 6.1 Ms (PAS)
19:00:46.9 UTC, 27.39N, 88.75E, 17 kms depth
Eight people were injured in Gangtok and there was also minor damage reported from the city. The quake was felt in eastern and north-eastern India, Bangladesh, Bhutan and Nepal.

21 August 1988 -  Udaipur Gahri, Nepal (Indo-Nepal Border region), Mw 6.8 (NEIC)
23:09:09 UTC / 04:39:09 IST, 26.755N 86.616
Nearly 900 people were killed in the border districts of Nepal and Bihar, India. Damage was also reported from Kathmandu and Sikkim. Felt over much of northern and eastern India and much of Nepal. Felt as far as New Delhi.

14 February 2006 - Mana, North Sikkim, Mw 5.3
27.377 N, 88.362 E, D=020.1 kms, OT=00:55:23 UTC
A moderate earthquake struck the Sikkim Himalayas on 14 February 2006 at 06:25 AM local time resulting in two deaths and minor damage to property in the state of Sikkim, India. It had a magnitude of Mw=5.3. This is the strongest earthquake in this immediate region since a Mw=6.3 earthquake on 19 November 1980.

18 May 2007 - Nambu, North Sikkim, Mb 4.6
27.302 N, 88.159 E, D=021.1 kms, OT=12:40:02 UTC
A light earthquake struck the Sikkim Himalayas on 18 May 2007 at 18:10 PM local time resulting in some panic in the state of Sikkim, India. It had a magnitude of Mb=4.6.

20 May 2007 - Singyang, North Sikkim, Mb 5.0
27.303 N, 88.191 E, D=021.1 kms, OT=14:18:18 UTC
A moderate earthquake struck the Sikkim Himalayas on 20 May 2007 at 19:48 PM local time resulting in some panic and minor damage in the state of Sikkim, India. It had a magnitude of Mb=5.0.