Reviewed by USGSIndonesia40y ago
M5.0 earthquake 68 km WSW of Tobelo, Indonesia
Tuesday, October 21, 1986, 21:57:59 UTC · 1.541°N, 127.424°E
A magnitude 5.0 earthquake struck 68 km WSW of Tobelo, Indonesia on Tuesday, October 21, 1986, 21:57:59 UTC, at a depth of 142.1 km (intermediate). It is the strongest earthquake within 300 km since an M5.0 on October 20, 1986.
- Magnitude
- 5.0
- Moderate · mb
- Depth
- 142 km
- Intermediate
- 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
477 tons of TNT
That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.
Tectonic setting
86 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: intermediate
142 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 2 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.0 on October 25, 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 801 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 · 151 km NE of this epicenter
- 7.7148 km SE of Tondano, IndonesiaMay 14, 1932 · 214 km SW of this epicenter
- 7.7121 km E of Bitung, IndonesiaAugust 10, 1968 · 134 km W of this epicenter
- 7.564 km NNW of Ternate, IndonesiaJune 25, 1907 · 36 km SW of this epicenter
- 7.5146 km NW of Ternate, IndonesiaAugust 14, 1986 · 104 km W of this epicenter
- 7.5210 km SSE of Sarangani, PhilippinesAugust 17, 1912 · 277 km NW of this epicenter
- 7.3108 km SE of Tondano, IndonesiaMay 5, 1908 · 244 km SW of this epicenter
- 7.2182 km WNW of Tobelo, IndonesiaOctober 10, 1938 · 139 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 17 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 159 recorded deaths. The most severe:
- 1845M7.0
N Sulawesi: Menado, Tikala, Tomohon
8 Feb 1845 · 286 km away · intensity IX
118 deathsModerate damage ($1–5M)tsunami
- 1855
Maluku: Ternate Island
14 Jul 1855 · 84 km away · intensity IX
34 deathsModerate damage ($1–5M)
- 1932M7.7
Sulawesi: Kakas,Langowan,Poso,Tondano
14 May 1932 · 214 km away · intensity VII
7 deathsSevere damage ($5–24M)tsunami
- 1858M7.3
N. Moluccas Islands
13 Dec 1858 · 169 km away
Severe damage ($5–24M)tsunami
- 1889M8.0
N. Moluccas Islands
6 Sep 1889 · 144 km away
Moderate damage ($1–5M)tsunami
- 1859M7.3
Sulawesi
29 Jul 1859 · 273 km away
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.