Reviewed by USGSIndonesia41y ago
M3.5 earthquake 129 km SSE of Manokwari, Indonesia
Thursday, November 21, 1985, 15:21:06 UTC · 1.984°S, 134.399°E
A magnitude 3.5 earthquake struck 129 km SSE of Manokwari, Indonesia on Thursday, November 21, 1985, 15:21:06 UTC, at a depth of 10.0 km (shallow).
- Magnitude
- 3.5
- Minor · mb
- Depth
- 10 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
3 tons of TNT
That is about 1/5,615 of the Hiroshima bomb. A magnitude 5.0 releases about 178 times more energy.
Tectonic setting
218 km
from the nearest mapped plate boundary, between the Maoke and Birds Head plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
10 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 M5.2 on November 26, 1985. 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 185 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.21914 Biak EarthquakeMay 26, 1914 · 283 km E of this epicenter
- 7.955 km S of Biak, IndonesiaSeptember 12, 1979 · 186 km E of this epicenter
- 7.736 km NNE of Nabire, IndonesiaJanuary 13, 1916 · 187 km SE of this epicenter
- 7.65 km SW of Manokwari, IndonesiaApril 27, 1944 · 127 km N of this epicenter
- 7.6138 km SW of Insrom, IndonesiaMay 27, 1947 · 70 km E of this epicenter
- 7.1152 km NNE of Tual, IndonesiaFebruary 15, 1936 · 292 km SW of this epicenter
- 7.182 km SE of Biak, IndonesiaJune 22, 1957 · 245 km E of this epicenter
- 7.1127 km SE of Manokwari, IndonesiaNovember 17, 1985 · 69 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 365 recorded deaths. The most severe:
- 1864M7.8
Irian Jaya: Manokwari
23 May 1864 · 128 km away · intensity VII
250 deathsSevere damage ($5–24M)tsunami
- 1979M7.9
New Guinea: Irian Jaya
12 Sep 1979 · 186 km away
115 deathsSevere damage ($5–24M)tsunami
- 1957M7.3
New Guinea: Irian Jaya
22 Jun 1957 · 294 km away
Severe damage ($5–24M)tsunami
- 1914M8.1
New Guinea: Irian Jaya: Japen
26 May 1914 · 283 km away · intensity IX
Moderate damage ($1–5M)tsunami
- 1985M7.1
New Guinea: Irian Jaya: Manokwari
17 Nov 1985 · 69 km away · intensity VIII
Limited damage (under $1M)
- 1938
New Guinea: Fakfak
13 Feb 1938 · 259 km away
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.