M5.5 earthquake 231 km NNE of Tobelo, Indonesia

Monday, February 17, 1969, 01:26:05 UTC · 3.746°N, 128.560°E

A magnitude 5.5 earthquake struck 231 km NNE of Tobelo, Indonesia on Monday, February 17, 1969, 01:26:05 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M6.4 on February 17, 1969.

Magnitude: 5.5; Moderate · mw
Depth: 15 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

2 kilotons of TNT

That is about 1/7 of the Hiroshima bomb. It released about 5 times the energy of a magnitude 5.0.

Tectonic setting

10 km

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

Depth: shallow

15 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 5 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M6.4 on February 20, 1969. 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 107 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 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

1936M7.7
Talaud Islands
1 Apr 1936 · 243 km away · intensity IX
Moderate damage ($1–5M)tsunami
1910M6.7
Sulawesi-N. Moluccas Islands
18 Dec 1910 · 175 km away · intensity VIII
Limited damage (under $1M)tsunami
1957M7.6
Philippines
24 Sep 1957 · 228 km away
1910M7.5
Talaud Islands
16 Dec 1910 · 296 km away
1969M7.5
Talaud Islands, Mindanao, Visayan
30 Jan 1969 · 174 km away
1846M7.3
N. Moluccas Islands
25 Jan 1846 · 300 km away
tsunami

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

Nearby trackers