Magnitude7.1

Reviewed by USGSIndonesia91y ago

M7.1 earthquake 86 km WSW of Pangkalan Brandan, Indonesia

Saturday, September 19, 1936, 01:01:47 UTC · 3.681°N, 97.578°E

A magnitude 7.1 earthquake struck 86 km WSW of Pangkalan Brandan, Indonesia on Saturday, September 19, 1936, 01:01:47 UTC, at a depth of 20.0 km (shallow). It is the strongest earthquake within 300 km since an M8.2 on January 4, 1907.

Magnitude
7.1
Major · mw
Depth
20 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: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

587 kilotons of TNT

That is about 39 times the Hiroshima bomb. It released about 1,230 times the energy of a magnitude 5.0.

Tectonic setting

107 km

from the nearest mapped plate boundary, between the Sunda and Burma plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

20 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 200 km

USGS lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M6.2 on September 19, 1936. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M71h6h1d3d7d14d30dMainshock M7.1
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 6.2109 km WSW of Pangkalan Brandan, Indonesia91y ago · 23 km W of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 20 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 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,205 recorded deaths. The most severe:

  1. 1907M8.2

    Nw Sumatra: Gunungsitoli, Barus

    4 Jan 1907 · 253 km away

    2,188 deathsSevere damage ($5–24M)tsunami

  2. 1936

    N Sumatera: Tapanuli, Karo

    9 Sep 1936 · 22 km away · intensity VIII

    17 deathsModerate damage ($1–5M)

  3. 1843M7.3

    Sw. Sumatra

    5 Jan 1843 · 247 km away · intensity XI

    Severe damage ($5–24M)tsunami

  4. 1837M7.3

    Banda Atjeh

    29 Sep 1837 · 267 km away

    Moderate damage ($1–5M)tsunami

  5. 1892

    Sumatra: Padangsidimpuan, Lake Toba

    17 May 1892 · 251 km away · intensity VI

    Moderate damage ($1–5M)tsunami

  6. 1861M7.0

    Sw. Sumatra

    26 Apr 1861 · 298 km away

    tsunami

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

Nearby trackers

Closest city pages