Reviewed by USGSSolomon Islands96y ago
M6.6 earthquake 155 km SSW of Kirakira, Solomon Islands
Saturday, October 3, 1931, 21:55:20 UTC · 11.772°S, 161.424°E
A magnitude 6.6 earthquake struck 155 km SSW of Kirakira, Solomon Islands on Saturday, October 3, 1931, 21:55:20 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.8 on October 3, 1931.
- Magnitude
- 6.6
- Strong · mw
- Depth
- 15 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: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
112 kilotons of TNT
That is about 7 times the Hiroshima bomb. It released about 234 times the energy of a magnitude 5.0.
Tectonic setting
56 km
from the nearest mapped plate boundary, between the Pacific and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
15 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 100 km
USGS lists 2 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M7.0 on October 3, 1931. 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 21 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8108 km SW of Kirakira, Solomon IslandsOctober 3, 1931 · 77 km N of this epicenter
- 7.547 km ESE of Kirakira, Solomon IslandsDecember 10, 1910 · 154 km NE of this epicenter
- 7.334 km WNW of Kirakira, Solomon IslandsApril 12, 1926 · 159 km N of this epicenter
- 7.341 km ESE of Malango, Solomon IslandsFebruary 19, 1906 · 257 km NW of this epicenter
- 7.3128 km SE of Kirakira, Solomon IslandsApril 11, 1914 · 151 km E of this epicenter
- 7.084 km SE of Honiara, Solomon IslandsDecember 9, 1909 · 223 km NW of this epicenter
- 6.853 km WSW of Kirakira, Solomon IslandsOctober 27, 1918 · 133 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 3 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 50 recorded deaths. The most severe:
- 1931M7.8
San Cristobal Island
3 Oct 1931 · 103 km away
50 deathsSevere damage ($5–24M)tsunami
- 1931M7.7
Solomon Islands
10 Oct 1931 · 202 km away
- 1926M7.5
Solomon Islands
12 Apr 1926 · 202 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.