:: ASC :: Amateur Seismic Centre :: ASC :: Amateur Seismic Centre

:: ASC :: Amateur Seismic Centre

Website Guide   Home Recent Earthquakes 2009 Andaman Sea Swarm

About Us | Quake Alerts | Search

Recent Earthquakes
Felt An Earthquake?

Historical Intensity Maps
South Asia Seismicity
Great Earthquakes
Tsunamis & Seiches
GSHAP Hazard Maps
Seismology Links
Be Earthquake Safe!

 

Advertisement

 

Last updated on 31 July 2009, 08:24 AM NZST (GMT+12:00)

Andaman Sea Swarm, 2009

Date:

July 2009

Epicentre:

E of Little Andaman, India

Time:

- multiple events -

Latitude:

- multiple events -

Longitude:

- multiple events -

Depth:

- multiple events -

Magnitude:

- multiple events -

Additional Info


Map Disclaimer


A swarm of light to moderate (M4.0-4.9 termed as "light" and M5.0-5.9 termed as "moderate") earthquakes began in the Andaman Sea along the Andaman Sea Ridge on 26 July 2009. The blue squares mark all earthquakes in this sequence that are also listed in the table below. The latest event listed in the table is shown as a red square.

The largest event recorded so far has been a Mb=5.3 earthquake at 05:14 UTC on 28 July 2009 (10:44 IST). Since the first event in this sequence at 06:45 UTC on 26 July 2009, that was large enough to be detected by global seismological networks, there have been over thirty recorded events (4.4<M<5.3). At least six events have had magnitudes greater than Mb=5.0 (5.0<M<5.3). Activity appears to have reduced from thirty-two recorded events on 26 July from 06:45 UTC to 23:59 UTC, to just four events on 27 July. The last event large enough to be located globally occurred at 19:14 UTC on 28 July.

Thus far, none of the earthquakes are thought to have been felt in the Andaman & Nicobar Islands or in coastal Thailand. However, if you felt any of these earthquakes, please take the time to fill out a felt report questionnaire.

Due to the magnitudes of the earthquakes so far, the risk of a local tsunami in the Andaman Sea from this sequence at this point in time is minimal. However, please be sure to check for any near-real time changes in the situation in the Indian Ocean at the Pacific Tsunami Warning Centre (PTWC).

Earthquake swarms are common along the Andaman Spreading Ridge and are associated with extension (sea floor spreading also known as rifting) along this feature that defines the boundary between the Burma and the Sunda micro-plates. This is the most significant swarm in the Andaman Sea, in terms of the size of the events, since a swarm between 26-30 January 2005 to the east of the islands of Nancowry and Camorta in the Nicobar Islands.

Date

UTC

M

T

Latitude

Longitude

Depth

Location

Network

28july09

19:14:05

4.9

Mb

10.549

94.206

004.0

Andaman Sea Ridge

NEIC

28july09

05:14:58

5.3

Mb

10.757

94.089

010.0

Andaman Sea Ridge

NEIC

28july09

05:10:59

4.8

Mb

10.460

94.500

010.0

Andaman Sea Ridge

GSR

27july09

21:15:01

4.8

Mb

10.648

94.337

002.0

Andaman Sea Ridge

NEIC

27july09

12:08:15

4.8

Mb

10.722

94.340

010.0

Andaman Sea Ridge

NEIC

27july09

03:31:53

4.6

Mb

10.710

94.200

033.0

Andaman Sea Ridge

GSR

27july09

02:09:16

4.8

Mb

10.730

94.140

033.0

Andaman Sea Ridge

GSR

26july09

21:49.24

5.1

Mb

10.599

94.217

010.0

Andaman Sea Ridge

NEIC

26july09

19:45:06

5.0

Mb

10.625

94.257

010.0

Andaman Sea Ridge

NEIC

26july09

17:47:58

4.6

Mb

10.620

94.300

026.0

Andaman Sea Ridge

GFZ

26july09

17:01:07

4.8

Mb

10.780

94.480

033.0

Andaman Sea Ridge

GSR

26july09

16:53:11

4.4

Mb

10.740

95.540

024.0

Andaman Sea Ridge

GFZ

26july09

16:12:54

4.5

Mb

10.840

94.480

025.0

Andaman Sea Ridge

GFZ

26july09

15:51:00

4.9

Mb

10.494

94.239

010.0

Andaman Sea Ridge

NEIC

26july09

15:27:04

5.2

Mb

11.862

94.351

010.0

Andaman Sea Ridge

NEIC

26july09

14:58:13

4.9

Mb

10.601

94.115

010.0

Andaman Sea Ridge

NEIC

26july09

14:26:57

4.8

Mb

11.010

95.000

033.0

Andaman Sea Ridge

GSR

26july09

13:48:51

4.9

Mb

10.495

93.892

010.0

Andaman Sea Ridge

NEIC

26july09

13:29:14

5.1

Mb

10.666

94.296

010.0

Andaman Sea Ridge

NEIC

26july09

13:19:37

5.0

Mb

10.720

94.310

033.0

Andaman Sea Ridge

GSR

26july09

12:48:36

4.9

Mb

10.696

94.314

010.0

Andaman Sea Ridge

NEIC

26july09

12:34:33

4.8

Mb

10.701

94.380

010.0

Andaman Sea Ridge

NEIC

26july09

12:25:51

4.8

Mb

10.555

94.075

010.0

Andaman Sea Ridge

NEIC

26july09

12:14:28

4.4

Mb

10.820

94.380

020.0

Andaman Sea Ridge

GFZ

26july09

11:55:44

4.8

Mb

10.615

94.244

010.0

Andaman Sea Ridge

NEIC

26july09

11:18:52

4.5

Mb

10.828

94.493

010.0

Andaman Sea Ridge

NEIC

26july09

10:58:01

4.6

Mb

10.684

94.367

010.0

Andaman Sea Ridge

NEIC

26july09

10:42:29

4.7

Mb

10.839

94.404

010.0

Andaman Sea Ridge

NEIC

26july09

10:14:16

4.9

Mb

10.724

94.379

010.0

Andaman Sea Ridge

NEIC

26july09

09:40:26

4.8

Mb

10.651

94.414

010.0

Andaman Sea Ridge

NEIC

26july09

09:06:47

4.6

Mb

11.129

94.894

010.0

Andaman Sea Ridge

NEIC

26july09

08:40:56

4.8

Mb

10.741

94.420

010.0

Andaman Sea Ridge

NEIC

26july09

08:11:16

4.7

Mb

10.725

94.347

010.0

Andaman Sea Ridge

NEIC

26july09

07:40:13

4.8

Mb

10.736

94.288

010.0

Andaman Sea Ridge

NEIC

26july09

06:54:48

4.8

Mb

10.887

94.493

010.0

Andaman Sea Ridge

NEIC

26july09

06:49:25

4.8

Mb

10.820

94.360

019.0

Andaman Sea Ridge

GFZ

26july09

06:45:37

4.7

Mb

10.891

94.480

010.0

Andaman Sea Ridge

NEIC

Earthquakes swarms can be defined as a series of earthquakes in the same magnitude range that are closely spaced in time and originating in the same region but devoid of a mainshock (principal large event). They can last from as little as a few hours to as long as several months (eg. Matsushiro, Japan, 1965-1966). Swarms can be precursory or non-precursory but establishing either is only feasible in hindsight. Earthquake swarms have occurred in other parts of the Indian mainland including Nanded (Maharashtra) in 2006-2008, Jind (Haryana) in 2003, Bhavnagar (Gujarat) in 2000.


References
01) National Earthquake Information Centre
(NEIC), Golden, USA.
02) Geophysical Survey of the Russian Academy of Sciences (GSR), Obninsk, Russia.
03)
GeoForschungs Zentrum (GFZ), Potzdam, Germany.


Page Citation
Information on this page may be reproduced in print or electronically but it is requested that a citation be given to this website in the form of a link i.e. "www.asc-india.org".

Map Disclaimer
International boundaries of India (especially Arunachal Pradesh, Jammu & Kashmir, Himachal Pradesh and Uttarakhand) on the displayed map are from Google Maps. These do not conform to the external boundaries of India recognized by the Survey of India. That they are displayed on this page via Google Maps, is only for display purposes and this should not be misinterpreted as an endorsement of these boundaries by the Amateur Seismic Centre (ASC).

Page Updated: 31 Jul 2009 | Website Disclaimer

Amateur Seismic Centre, Pune,