Earthquakes in Mizoram & Tripura, India

State - Mizoram, India
Capital - Aizwal
Population - 891,058 (2001)

State - Tripura, India
Capital - Agartala
Population - 3,191,168 (2001)

Population per district (largest per state)
West Tripura (Tripura) - pop. 1,532,982
Aizwal (Mizoram) - pop. 325,676

Earthquake History
In Mizoram, lie the southern most end of the Purbachal Himalayan range. Their folded structure is a synclinorium consisting of broad synclines and tight-faulted anticlines. Earthquakes in this region are generally shallow, though a few quakes of intermediate depth have occured. Most deeper earthquakes occur along and across the international border, in Myanmar's Chin Division. Earthquake activity in Tripura is mainly shallow. The Dauki Fault which follows the international border of India and Bangladesh in Meghalaya passes though northern sections of Tripura. The other major threat is from the Madhupur Fault in Bangladesh. 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 by the Bureau of Indian Standards (BIS). Both the states of Mizoram and Tripura lie entirely in Zone V. 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 Mizoram & Tripura).

Largest Instrumented Earthquake in Mizoram & Tripura
22 November 1997 - Southern Mizoram, Mw 6.1 (NEIC)
11:23:06.0 UTC, 22.212N, 92.702E, 54kms depth
No fatalities were reported in Mizoram, however, 23 people were killed when a 5-storey building collapsed in Chittagong, Bangaldesh. Tremors wee felt as far as Rangpur and Rajshahi.

Significant Earthquakes in Mizoram & Tripura
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 August 1920 - West of Saitlan, Chin Division (Indo-Myanmar Border region) , 6.0 (TS)
06:59:08 UTC, 22.20N, 93.20E

24 December 1950 - NW of Srimangal, Chittagong Division (Bangladesh), 6.3 (TS)
22:35:20.10 UTC, 24.40N, 91.70E

12 December 1957 - South of Silchar, Cachar District (Assam-Mizoram bdr region), 6.0 (TS)
24.500 93.000

14 November 1967 - NE of Agartala (Indo-Bangladesh Border region), 5.1 (TS)
00:04:17.80 UTC, 24.00N, 91.50E

27 December 1968 - NE of Agartala (Indo-Bangladesh Border region), 5.2 (TS)
14:38:11.60 UTC,24.10N, 91.60E

2 February 1971 - East of Agartala (Tripura), Mb5.4 (NEIS), 5.4 (TS)
07:59:57 UTC, 23.80N, 91.80E

21 May 1984 - SE of Agartala (Tripura), Mb 5.3 (NEIS)
09:59:05.0 UTC, 23.6573N, 91.5078E, 12.60 kms depth

30 December 1984 - South of Silchar (Assam-Mizoram border region), Mw6.0 (HRV)
23:33:37 UTC, 24.64N, 92.89E, 23 kms depth
20 people were killed in Assam's Cachar district. This earthquake was forecast on the basis of foreshock activity and then the following quiescience.

13 April 1989 - Tripura-Mizoram-Assam border region, Mb 5.1 (NEIC)
07:25:33.0 UTC, 24.4041N, 92.4312E, 9.90 ksm depth

22 November 1997 - Southern Mizoram, Mw 6.1 (NEIC)
11:23:06.0 UTC, 22.212N, 92.702E, 54kms depth
No fatalities were reported in Mizoram, however, 23 people were killed when a 5-storey building collapsed in Chittagong, Bangaldesh. Tremors wee felt as far as Rangpur and Rajshahi.