M7.7 earthquake 121 km E of Bitung, Indonesia

Saturday, August 10, 1968, 02:07:05 UTC · 1.475°N, 126.221°E

A magnitude 7.7 earthquake struck 121 km E of Bitung, Indonesia on Saturday, August 10, 1968, 02:07:05 UTC, at a depth of 20.9 km (shallow). It is the strongest earthquake within 300 km since an M7.7 on September 8, 1966.

Magnitude: 7.7; Major · mw
Depth: 21 km; Shallow
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

5.0 megatons of TNT

That is about 332 times the Hiroshima bomb. It released about 10,471 times the energy of a magnitude 5.0.

Tectonic setting

12 km

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

Depth: shallow

21 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 12 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.5 on August 10, 1968. 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 130 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 20 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,965 recorded deaths. The most severe:

1856
Sangihe Pulau (Volcanic)
2 Mar 1856 · 257 km away
2,806 deathsSevere damage ($5–24M)tsunami
1845M7.0
N Sulawesi: Menado, Tikala, Tomohon
8 Feb 1845 · 152 km away · intensity IX
118 deathsModerate damage ($1–5M)tsunami
1855
Maluku: Ternate Island
14 Jul 1855 · 142 km away · intensity IX
34 deathsModerate damage ($1–5M)
1932M7.7
Sulawesi: Kakas,Langowan,Poso,Tondano
14 May 1932 · 127 km away · intensity VII
7 deathsSevere damage ($5–24M)tsunami
1858M7.3
N. Moluccas Islands
13 Dec 1858 · 58 km away
Severe damage ($5–24M)tsunami
1889M8.0
N. Moluccas Islands
6 Sep 1889 · 53 km away
Moderate damage ($1–5M)tsunami

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

Nearby trackers