Reviewed by USGSIndonesia40y ago
M4.6 earthquake 52 km NE of Sofifi, Indonesia
Tuesday, September 9, 1986, 14:42:44 UTC · 1.095°N, 127.865°E
A magnitude 4.6 earthquake struck 52 km NE of Sofifi, Indonesia on Tuesday, September 9, 1986, 14:42:44 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M4.8 on September 6, 1986.
- Magnitude
- 4.6
- 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
120 tons of TNT
That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.
Tectonic setting
101 km
from the nearest mapped plate boundary, between the Sunda and Birds Head plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M5.6 on September 9, 1986. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 714 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.790 km NE of Tobelo, IndonesiaSeptember 8, 1966 · 160 km NE of this epicenter
- 7.7148 km SE of Tondano, IndonesiaMay 14, 1932 · 234 km W of this epicenter
- 7.7121 km E of Bitung, IndonesiaAugust 10, 1968 · 188 km W of this epicenter
- 7.564 km NNW of Ternate, IndonesiaJune 25, 1907 · 81 km W of this epicenter
- 7.5146 km NW of Ternate, IndonesiaAugust 14, 1986 · 169 km NW of this epicenter
- 7.3108 km SE of Tondano, IndonesiaMay 5, 1908 · 272 km W of this epicenter
- 7.2182 km WNW of Tobelo, IndonesiaOctober 10, 1938 · 209 km NW of this epicenter
- 7.1129 km WNW of Ternate, IndonesiaMay 3, 1925 · 174 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 15 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 41 recorded deaths. The most severe:
- 1855
Maluku: Ternate Island
14 Jul 1855 · 71 km away · intensity IX
34 deathsModerate damage ($1–5M)
- 1932M7.7
Sulawesi: Kakas,Langowan,Poso,Tondano
14 May 1932 · 234 km away · intensity VII
7 deathsSevere damage ($5–24M)tsunami
- 1858M7.3
N. Moluccas Islands
13 Dec 1858 · 208 km away
Severe damage ($5–24M)tsunami
- 1889M8.0
N. Moluccas Islands
6 Sep 1889 · 180 km away
Moderate damage ($1–5M)tsunami
- 1859M7.3
Sulawesi
29 Jul 1859 · 289 km away
Moderate damage ($1–5M)tsunami
- 1840
Maluku: Ternate Island
14 Feb 1840 · 68 km away
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.