M7.2 earthquake in Nicobar Islands, India region

Sunday, July 24, 2005, 15:42:06 UTC · 7.920°N, 92.190°E

A magnitude 7.2 earthquake struck in Nicobar Islands, India region on Sunday, July 24, 2005, 15:42:06 UTC, at a depth of 16.0 km (shallow). USGS received 25 “Did You Feel It?” reports, with a maximum reported intensity of IV (light). It is the strongest earthquake within 300 km since an M7.2 on December 26, 2004.

Magnitude: 7.2; Major · mwc
Depth: 16 km; Shallow
Felt reports: 25; Max intensity IV
Est. shaking: V; Moderate (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

951 kilotons of TNT

That is about 63 times the Hiroshima bomb. It released about 1,995 times the energy of a magnitude 5.0.

Tectonic setting

38 km

from the nearest mapped plate boundary, between the Indian and Burma plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

16 km

Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.

Did You Feel It?

Where it was felt

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
Madras, Tamil Nadu, India	III · Weak	9	1424 km
Banda Aceh, Aceh, Indonesia	III · Weak	2	434 km
Georgetown, Pulau Pinang, Malaysia	II · Weak	2	941 km
Wattala, Gampaha, Sri Lanka	IV · Light	1	1361 km
Phuket, Phuket, Thailand	III · Weak	1	682 km
Kotte, Colombo, Sri Lanka	III · Weak	1	1361 km
Barddhaman, Bangla, India	II · Weak	1	1757 km
Kuala Lumpur, Kuala Lumpur, Malaysia	II · Weak	1	1179 km
Tanggalla, Hambantota, Sri Lanka	II · Weak	1	1277 km
Mamallapuram, Tamil Nadu, India	I · Not felt	1	1412 km

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 200 km

USGS lists 60 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.6 on July 25, 2005. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 441 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 5 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

1881M7.9
Andaman I,Nicobar I
31 Dec 1881 · 72 km away
Severe damage ($5–24M)tsunami
1982M6.3
Little Nicobar Island
20 Jan 1982 · 227 km away · intensity VIII
Moderate damage ($1–5M)
2005M7.2
Andaman Islands, Nicobar Islands
24 Jul 2005 · 0 km away
Limited damage (under $1M)
1847
Little Nicobar Island
31 Oct 1847 · 175 km away · intensity X
Limited damage (under $1M)tsunami
1955M7.3
Little Nicobar Island
17 May 1955 · 255 km away
tsunami

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers