Reviewed by USGSIndonesia17y ago
M4.2 earthquake in Kepulauan Mentawai region, Indonesia
Tuesday, December 8, 2009, 22:07:35 UTC · 1.480°S, 99.485°E
A magnitude 4.2 earthquake struck in Kepulauan Mentawai region, Indonesia on Tuesday, December 8, 2009, 22:07:35 UTC, at a depth of 38.6 km (shallow).
- Magnitude
- 4.2
- Light · mb
- Depth
- 39 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
30 tons of TNT
That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.
Tectonic setting
138 km
from the nearest mapped plate boundary, between the Sunda and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
39 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 50 km
USGS lists 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M6.0 on December 23, 2009. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.6126 km WSW of Padang, Indonesia17y ago · 14 km W of this epicenter
- 4.6117 km WSW of Padang, Indonesia17y ago · 5 km SW of this epicenter
- 4.593 km WSW of Padang, Indonesia17y ago · 20 km NE of this epicenter
- 4.8119 km WSW of Padang, Indonesia17y ago · 10 km W of this epicenter
- 6.0119 km WSW of Padang, Indonesia17y ago · 11 km NW of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 482 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.987 km SW of Sungai Penuh, IndonesiaSeptember 12, 2007 · 197 km SE of this epicenter
- 7.726 km S of Sijunjung, IndonesiaJune 9, 1943 · 172 km E of this epicenter
- 7.630 km WSW of Pariaman, IndonesiaSeptember 30, 2009 · 95 km NE of this epicenter
- 7.6212 km W of Pariaman, IndonesiaDecember 28, 1935 · 192 km NW of this epicenter
- 7.676 km SSW of Sungai Penuh, IndonesiaJune 3, 1909 · 234 km SE of this epicenter
- 7.2164 km WSW of Sungai Penuh, IndonesiaFebruary 25, 2008 · 124 km SE of this epicenter
- 7.1190 km SSW of Sibolga, IndonesiaNovember 17, 1984 · 247 km NW of this epicenter
- 7.095 km W of Pariaman, IndonesiaApril 1, 1998 · 107 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 27 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 3,638 recorded deaths. The most severe:
- 2009M7.5
Sumatra: Padang
30 Sep 2009 · 95 km away
1,117 deaths$2.2 billion damagetsunami
- 1861M8.5
Lagundi, Simuk, Tello I
16 Feb 1861 · 227 km away · intensity IX
1,105 deathsModerate damage ($1–5M)tsunami
- 1861M7.0
Sw. Sumatra
9 Mar 1861 · 234 km away
950 deathsSevere damage ($5–24M)tsunami
- 1797M8.0
Sw. Sumatra
10 Feb 1797 · 173 km away · intensity IX
300 deathsModerate damage ($1–5M)tsunami
- 1995M6.8
Sumatera, Jambi Province
6 Oct 1995 · 226 km away
84 deathsExtreme damage ($25M+)
- 2007M6.4
Sumatra: Southern
6 Mar 2007 · 157 km away · intensity VIII
67 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.