M8.6 earthquake 78 km WSW of Singkil, Indonesia

Monday, March 28, 2005, 16:09:36 UTC · 2.085°N, 97.108°E

A magnitude 8.6 earthquake struck 78 km WSW of Singkil, Indonesia on Monday, March 28, 2005, 16:09:36 UTC, at a depth of 30.0 km (shallow). It is the strongest earthquake within 300 km since an M9.1 on December 26, 2004.

Magnitude: 8.6; Great · mww
Depth: 30 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: VIII; Severe (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 400 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

120 megatons of TNT

That is about 7,955 times the Hiroshima bomb. It released about 251,189 times the energy of a magnitude 5.0.

Tectonic setting

37 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

30 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 400 km

USGS lists 973 M2.5+ earthquakes within 400 km in the following 30 days; the largest was M6.4 on April 16, 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 298 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 20 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 232,379 recorded deaths. The most severe:

2004M9.1
Sumatra: Aceh: Off West Coast
26 Dec 2004 · 184 km away
227,899 deaths$10 billion damagetsunami
1907M8.2
Nw Sumatra: Gunungsitoli, Barus
4 Jan 1907 · 187 km away
2,188 deathsSevere damage ($5–24M)tsunami
2005M8.6
Sumatera: Sw
28 Mar 2005 · 0 km away
1,319 deaths$37 million damagetsunami
1861M7.0
Sw. Sumatra
9 Mar 1861 · 251 km away
950 deathsSevere damage ($5–24M)tsunami
1936
N Sumatera: Tapanuli, Karo
9 Sep 1936 · 163 km away · intensity VIII
17 deathsModerate damage ($1–5M)
2002M7.3
Sumatera: Simeulue
2 Nov 2002 · 140 km away
3 deathsSevere damage ($5–24M)

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

Nearby trackers