M6.8 earthquake in Molucca Sea

Thursday, December 9, 1993, 11:38:27 UTC · 0.425°N, 125.891°E

A magnitude 6.8 earthquake struck in Molucca Sea on Thursday, December 9, 1993, 11:38:27 UTC, at a depth of 15.9 km (shallow). It is the strongest earthquake within 300 km since an M6.9 on December 9, 1993.

Magnitude: 6.8; Strong · mw
Depth: 16 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: 100 km aftershock search area

In context

How big was it, and why here?

Energy released

239 kilotons of TNT

That is about 16 times the Hiroshima bomb. It released about 501 times the energy of a magnitude 5.0.

Tectonic setting

14 km

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

Depth: shallow

16 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 32 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.9 on December 12, 1993. 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 1,094 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 19 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 159 recorded deaths. The most severe:

1845M7.0
N Sulawesi: Menado, Tikala, Tomohon
8 Feb 1845 · 165 km away · intensity IX
118 deathsModerate damage ($1–5M)tsunami
1855
Maluku: Ternate Island
14 Jul 1855 · 162 km away · intensity IX
34 deathsModerate damage ($1–5M)
1932M7.7
Sulawesi: Kakas,Langowan,Poso,Tondano
14 May 1932 · 4 km away · intensity VII
7 deathsSevere damage ($5–24M)tsunami
1858M7.3
N. Moluccas Islands
13 Dec 1858 · 65 km away
Severe damage ($5–24M)tsunami
1989M5.6
Molucca Passage: Morotai, Tanawangu
8 Mar 1989 · 75 km away
Severe damage ($5–24M)
1889M8.0
N. Moluccas Islands
6 Sep 1889 · 75 km away
Moderate damage ($1–5M)tsunami

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

Nearby trackers