QuakeScout
Magnitude6.5

Reviewed by USGSIndonesia107y ago

M6.5 earthquake 290 km SSE of Amahai, Indonesia

Wednesday, March 23, 1921, 22:44:14 UTC · 5.771°S, 129.905°E

A magnitude 6.5 earthquake struck 290 km SSE of Amahai, Indonesia on Wednesday, March 23, 1921, 22:44:14 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on June 9, 1920.

Magnitude
6.5
Strong · mw
Depth
15 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 earthquake

In context

How big was it, and why here?

Energy released

88 kilotons of TNT

That is about 6 times the Hiroshima bomb. It released about 184 times the energy of a magnitude 5.0.

Tectonic setting

82 km

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

Depth: shallow

15 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 has not published any M2.5+ earthquake within 100 km in the 30 days after this event.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 8 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 7.1196 km SSE of Ambon, IndonesiaJuly 4, 1914 · 107 km NW of this epicenter
  2. 7.0188 km SSE of Amahai, IndonesiaJune 9, 1920 · 103 km N of this epicenter
  3. 6.9Banda SeaOctober 30, 1909 · 130 km S of this epicenter
  4. 6.8Banda SeaNovember 23, 1918 · 144 km SW of this epicenter
  5. 6.7158 km SW of Tual, IndonesiaNovember 18, 1919 · 235 km SE of this epicenter
  6. 6.7284 km ENE of Lospalos, Timor LesteMay 30, 1909 · 241 km S of this epicenter
  7. 6.5264 km WSW of Tual, IndonesiaMay 5, 1915 · 90 km SE of this epicenter
  8. 6.4168 km SE of Amahai, IndonesiaJuly 2, 1920 · 157 km N of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 21 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 73 recorded deaths. The most severe:

  1. 1852M8.3

    Maluku: Bandanaira

    25 Nov 1852 · 60 km away · intensity IX

    60 deathsSevere damage ($5–24M)tsunami

  2. 1763

    Bandaneira

    12 Sep 1763 · 28 km away · intensity X

    7 deathsModerate damage ($1–5M)tsunami

  3. 1754M6.5

    Ambon Island

    18 Aug 1754 · 297 km away

    4 deathsModerate damage ($1–5M)tsunami

  4. 1711M7.0

    Banda Sea

    5 Sep 1711 · 221 km away

    2 deathsLimited damage (under $1M)tsunami

  5. 1710

    Bandaneira

    6 Mar 1710 · 138 km away · intensity IX

    Severe damage ($5–24M)tsunami

  6. 1802

    Banda Sea

    Aug 1802 · 298 km away · intensity X

    Moderate damage ($1–5M)tsunami

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

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