M7.3 earthquake 172 km NE of Lospalos, Timor Leste

Thursday, November 24, 1983, 05:30:34 UTC · 7.481°S, 128.168°E

A magnitude 7.3 earthquake struck 172 km NE of Lospalos, Timor Leste on Thursday, November 24, 1983, 05:30:34 UTC, at a depth of 178.5 km (intermediate). It is the strongest earthquake within 300 km since an M8.1 on November 4, 1963.

Magnitude: 7.3; Major · mw
Depth: 179 km; Intermediate
Felt reports: 0; Did You Feel It?
Est. shaking: VI; 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

1.3 megatons of TNT

That is about 89 times the Hiroshima bomb. It released about 2,818 times the energy of a magnitude 5.0.

Tectonic setting

64 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: intermediate

179 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

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 12 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.4 on December 12, 1983. 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 370 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 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 7 recorded deaths. The most severe:

1763
Bandaneira
12 Sep 1763 · 261 km away · intensity X
7 deathsModerate damage ($1–5M)tsunami
1963M8.3
Banda Sea
4 Nov 1963 · 170 km away
Limited damage (under $1M)
1908M6.6
Timor
23 Mar 1908 · 295 km away
Limited damage (under $1M)tsunami
1918M8.1
Banda Sea
18 Nov 1918 · 106 km away
1950M8.1
Banda Sea
2 Nov 1950 · 183 km away
1917M7.8
Banda Sea
30 Aug 1917 · 19 km away

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

Nearby trackers