Magnitude6.6

Reviewed by USGSIndonesia97y ago

M6.6 earthquake 68 km SSW of Pagar Alam, Indonesia

Saturday, February 14, 1931, 13:58:58 UTC · 4.610°S, 103.038°E

A magnitude 6.6 earthquake struck 68 km SSW of Pagar Alam, Indonesia on Saturday, February 14, 1931, 13:58:58 UTC, at a depth of 60.0 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on February 10, 1931.

Magnitude
6.6
Strong · mw
Depth
60 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
VII
Very strong (ShakeMap)
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

104 kilotons of TNT

That is about 7 times the Hiroshima bomb. It released about 219 times the energy of a magnitude 5.0.

Tectonic setting

241 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

60 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 100 km

USGS lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M6.5 on February 19, 1931. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M61h6h1d3d7d14d30dMainshock M6.6
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 6.5157 km SSW of Pagar Alam, Indonesia96y ago · 91 km SW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 22 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 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 20 recorded deaths. The most severe:

  1. 1914M7.6

    Sumatera

    25 Jun 1914 · 155 km away

    20 deathsLimited damage (under $1M)tsunami

  2. 1770M7.0

    Sumatra:

    1770 · 123 km away

    Severe damage ($5–24M)tsunami

  3. 1931M7.4

    Sw. Sumatra

    25 Sep 1931 · 54 km away · intensity VIII

    Limited damage (under $1M)tsunami

  4. 1818M7.0

    Sumatra: Bengkulu

    18 Mar 1818 · 184 km away · intensity IX

    Limited damage (under $1M)tsunami

  5. 1896M6.8

    Sw. Sumatra, Java

    10 Oct 1896 · 137 km away

    Limited damage (under $1M)tsunami

  6. 1930M6.0

    Java-S. Java Sea

    19 Jun 1930 · 274 km away

    tsunami

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

Nearby trackers

Closest city pages