Reviewed by USGSIndonesia55y ago
M6.9 earthquake 236 km W of Tual, Indonesia
Thursday, September 16, 1971, 06:22:40 UTC · 5.934°S, 130.635°E
A magnitude 6.9 earthquake struck 236 km W of Tual, Indonesia on Thursday, September 16, 1971, 06:22:40 UTC, at a depth of 129.0 km (intermediate). It is the strongest earthquake within 300 km since an M6.9 on July 8, 1964.
- Magnitude
- 6.9
- Strong · mw
- Depth
- 129 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
326 kilotons of TNT
That is about 22 times the Hiroshima bomb. It released about 684 times the energy of a magnitude 5.0.
Tectonic setting
85 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
129 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 100 km
USGS lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M5.7 on September 30, 1971. 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 81 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 · 147 km NE of this epicenter
- 8.11963 Banda Sea EarthquakeNovember 4, 1963 · 161 km SW of this epicenter
- 7.7Banda SeaNovember 2, 1950 · 188 km SW of this epicenter
- 7.5273 km WSW of Tual, IndonesiaJune 3, 1927 · 93 km S of this epicenter
- 7.1196 km SSE of Ambon, IndonesiaJuly 4, 1914 · 186 km NW of this epicenter
- 7.0188 km SSE of Amahai, IndonesiaJune 9, 1920 · 161 km NW of this epicenter
- 6.9Banda SeaOctober 30, 1909 · 154 km SW of this epicenter
- 6.9265 km SSE of Amahai, IndonesiaJuly 8, 1964 · 104 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 69 recorded deaths. The most severe:
- 1852M8.3
Maluku: Bandanaira
25 Nov 1852 · 124 km away · intensity IX
60 deathsSevere damage ($5–24M)tsunami
- 1763
Bandaneira
12 Sep 1763 · 71 km away · intensity X
7 deathsModerate damage ($1–5M)tsunami
- 1711M7.0
Banda Sea
5 Sep 1711 · 281 km away
2 deathsLimited damage (under $1M)tsunami
- 1710
Bandaneira
6 Mar 1710 · 176 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1938M8.6
New Guinea
1 Feb 1938 · 147 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1890
Bandaneira
23 Nov 1890 · 179 km away · intensity VII
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.