M4.5 earthquake 114 km W of Tomohon, Indonesia

Wednesday, May 9, 1990, 12:18:40 UTC · 1.453°N, 123.780°E

A magnitude 4.5 earthquake struck 114 km W of Tomohon, Indonesia on Wednesday, May 9, 1990, 12:18:40 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M5.0 on May 8, 1990.

Magnitude: 4.5; Light · mb
Depth: 33 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: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

85 tons of TNT

That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.

Tectonic setting

29 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

33 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 50 km

USGS lists 7 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M6.0 on May 15, 1990. 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 695 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 128 recorded deaths. The most severe:

1845M7.0
N Sulawesi: Menado, Tikala, Tomohon
8 Feb 1845 · 119 km away · intensity IX
118 deathsModerate damage ($1–5M)tsunami
1932M7.7
Sulawesi: Kakas,Langowan,Poso,Tondano
14 May 1932 · 262 km away · intensity VII
7 deathsSevere damage ($5–24M)tsunami
1990M7.6
Minahassa Peninsula: Bolaang-Gorontalo
18 Apr 1990 · 107 km away
3 deathsSevere damage ($5–24M)
1858M7.3
N. Moluccas Islands
13 Dec 1858 · 252 km away
Severe damage ($5–24M)tsunami
1989M5.6
Molucca Passage: Morotai, Tanawangu
8 Mar 1989 · 272 km away
Severe damage ($5–24M)
1889M8.0
N. Moluccas Islands
6 Sep 1889 · 279 km away
Moderate damage ($1–5M)tsunami

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

Nearby trackers