M5.1 earthquake in Nicobar Islands, India region

Friday, February 25, 2005, 13:30:07 UTC · 7.734°N, 94.170°E

A magnitude 5.1 earthquake struck in Nicobar Islands, India region on Friday, February 25, 2005, 13:30:07 UTC, at a depth of 24.2 km (shallow). It is the strongest earthquake within 300 km since an M5.4 on February 20, 2005.

Magnitude: 5.1; Moderate · mb
Depth: 24 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: —; No ShakeMap
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

674 tons of TNT

That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.

Tectonic setting

35 km

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

Depth: shallow

24 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

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

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 75 km

USGS lists 16 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.6 on February 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 510 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 14 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 9 recorded deaths. The most severe:

1936M7.3
Banda Aceh,Lhok Sukon,Lhoksemawe
23 Aug 1936 · 191 km away · intensity VIII
9 deathsModerate damage ($1–5M)tsunami
1881M7.9
Andaman I,Nicobar I
31 Dec 1881 · 211 km away
Severe damage ($5–24M)tsunami
1964M7.0
Banda Aceh
2 Apr 1964 · 265 km away · intensity VII
Severe damage ($5–24M)tsunami
1983M6.6
Sumatera: Banda Aceh
4 Apr 1983 · 232 km away · intensity VII
$1 million damage
1982M6.3
Little Nicobar Island
20 Jan 1982 · 90 km away · intensity VIII
Moderate damage ($1–5M)
2005M7.2
Andaman Islands, Nicobar Islands
24 Jul 2005 · 219 km away
Limited damage (under $1M)

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

Nearby trackers