Reviewed by USGS39y ago
M5.1 earthquake in Banda Sea
Sunday, September 20, 1987, 04:22:36 UTC · 6.329°S, 130.051°E
A magnitude 5.1 earthquake struck in Banda Sea on Sunday, September 20, 1987, 04:22:36 UTC, at a depth of 123.6 km (intermediate). It is the strongest earthquake within 300 km since an M5.4 on August 18, 1987.
- Magnitude
- 5.1
- Moderate · mb
- Depth
- 124 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
674 tons of TNT
That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.
Tectonic setting
28 km
from the nearest mapped plate boundary, between the Banda Sea and Timor plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
124 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 3 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.9 on October 6, 1987. 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 592 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.51938 Banda Sea EarthquakeFebruary 1, 1938 · 224 km NE of this epicenter
- 8.11963 Banda Sea EarthquakeNovember 4, 1963 · 85 km SW of this epicenter
- 7.7Banda SeaNovember 2, 1950 · 111 km SW of this epicenter
- 7.5273 km WSW of Tual, IndonesiaJune 3, 1927 · 74 km SE of this epicenter
- 7.3145 km NNE of Lospalos, Timor LesteAugust 30, 1917 · 291 km SW of this epicenter
- 7.3172 km NE of Lospalos, Timor LesteNovember 24, 1983 · 244 km SW of this epicenter
- 7.1196 km SSE of Ambon, IndonesiaJuly 4, 1914 · 162 km NW of this epicenter
- 7.1186 km NE of Lospalos, Timor LesteMay 15, 1962 · 232 km SW 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 69 recorded deaths. The most severe:
- 1852M8.3
Maluku: Bandanaira
25 Nov 1852 · 125 km away · intensity IX
60 deathsSevere damage ($5–24M)tsunami
- 1763
Bandaneira
12 Sep 1763 · 37 km away · intensity X
7 deathsModerate damage ($1–5M)tsunami
- 1711M7.0
Banda Sea
5 Sep 1711 · 284 km away
2 deathsLimited damage (under $1M)tsunami
- 1710
Bandaneira
6 Mar 1710 · 201 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1938M8.6
New Guinea
1 Feb 1938 · 224 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1975M5.9
Maluku: Bandanaira
15 Jan 1975 · 148 km away · intensity VII
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.