Reviewed by USGSIndonesia40y ago
M4.8 earthquake 74 km WSW of Tobelo, Indonesia
Saturday, September 6, 1986, 04:04:35 UTC · 1.517°N, 127.375°E
A magnitude 4.8 earthquake struck 74 km WSW of Tobelo, Indonesia on Saturday, September 6, 1986, 04:04:35 UTC, at a depth of 139.2 km (intermediate). It is the strongest earthquake within 300 km since an M4.8 on September 5, 1986.
- Magnitude
- 4.8
- Light · mb
- Depth
- 139 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
239 tons of TNT
That is about 1/63 of the Hiroshima bomb. A magnitude 5.0 releases about 2 times more energy.
Tectonic setting
89 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
139 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 50 km
USGS lists 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.7 on September 26, 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 791 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 · 157 km NE of this epicenter
- 7.7148 km SE of Tondano, IndonesiaMay 14, 1932 · 208 km SW of this epicenter
- 7.7121 km E of Bitung, IndonesiaAugust 10, 1968 · 128 km W of this epicenter
- 7.564 km NNW of Ternate, IndonesiaJune 25, 1907 · 30 km SW of this epicenter
- 7.5146 km NW of Ternate, IndonesiaAugust 14, 1986 · 100 km W of this epicenter
- 7.5210 km SSE of Sarangani, PhilippinesAugust 17, 1912 · 276 km NW of this epicenter
- 7.3108 km SE of Tondano, IndonesiaMay 5, 1908 · 238 km SW of this epicenter
- 7.2182 km WNW of Tobelo, IndonesiaOctober 10, 1938 · 137 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 · 281 km away · intensity IX
118 deathsModerate damage ($1–5M)tsunami
- 1855
Maluku: Ternate Island
14 Jul 1855 · 80 km away · intensity IX
34 deathsModerate damage ($1–5M)
- 1932M7.7
Sulawesi: Kakas,Langowan,Poso,Tondano
14 May 1932 · 208 km away · intensity VII
7 deathsSevere damage ($5–24M)tsunami
- 1858M7.3
N. Moluccas Islands
13 Dec 1858 · 163 km away
Severe damage ($5–24M)tsunami
- 1889M8.0
N. Moluccas Islands
6 Sep 1889 · 138 km away
Moderate damage ($1–5M)tsunami
- 1859M7.3
Sulawesi
29 Jul 1859 · 268 km away
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.