M5.1 earthquake 121 km WNW of Tobelo, Indonesia

Sunday, March 29, 1987, 23:24:04 UTC · 2.282°N, 127.062°E

A magnitude 5.1 earthquake struck 121 km WNW of Tobelo, Indonesia on Sunday, March 29, 1987, 23:24:04 UTC, at a depth of 69.3 km (shallow). It is the strongest earthquake within 300 km since an M6.1 on March 18, 1987.

Magnitude: 5.1; Moderate · mb
Depth: 69 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: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

674 tons of TNT

That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.

Tectonic setting

6 km

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

Depth: shallow

69 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 75 km

USGS lists 7 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.1 on April 16, 1987. 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 894 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 · 232 km away
2,806 deathsSevere damage ($5–24M)tsunami
1845M7.0
N Sulawesi: Menado, Tikala, Tomohon
8 Feb 1845 · 262 km away · intensity IX
118 deathsModerate damage ($1–5M)tsunami
1855
Maluku: Ternate Island
14 Jul 1855 · 167 km away · intensity IX
34 deathsModerate damage ($1–5M)
1932M7.7
Sulawesi: Kakas,Langowan,Poso,Tondano
14 May 1932 · 248 km away · intensity VII
7 deathsSevere damage ($5–24M)tsunami
1858M7.3
N. Moluccas Islands
13 Dec 1858 · 185 km away
Severe damage ($5–24M)tsunami
1889M8.0
N. Moluccas Islands
6 Sep 1889 · 169 km away
Moderate damage ($1–5M)tsunami

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

Nearby trackers