Reviewed by USGSJapan region96y ago
M6.2 earthquake in Volcano Islands, Japan region
Thursday, March 12, 1931, 10:40:39 UTC · 22.946°N, 143.337°E
A magnitude 6.2 earthquake struck in Volcano Islands, Japan region on Thursday, March 12, 1931, 10:40:39 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M6.6 on March 11, 1931.
- Magnitude
- 6.2
- 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
30 kilotons of TNT
That is about 2 times the Hiroshima bomb. It released about 63 times the energy of a magnitude 5.0.
Tectonic setting
83 km
from the nearest mapped plate boundary, between the Philippine Sea and Mariana 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 3 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.9 on March 12, 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 8 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.9Volcano Islands, Japan regionNovember 24, 1914 · 111 km SW of this epicenter
- 7.2Mariana Islands regionJuly 11, 1905 · 163 km S of this epicenter
- 7.1Volcano Islands, Japan regionMarch 23, 1913 · 122 km SW of this epicenter
- 6.6Volcano Islands, Japan regionMarch 11, 1931 · 49 km NE of this epicenter
- 6.2Volcano Islands, Japan regionMarch 9, 1929 · 213 km N of this epicenter
- 6.0Volcano Islands, Japan regionJanuary 12, 1920 · 89 km E of this epicenter
- 5.7Volcano Islands, Japan regionSeptember 5, 1928 · 99 km E of this epicenter
- 5.6Volcano Islands, Japan regionJuly 1, 1917 · 217 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 1 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1914M8.1
Volcano Islands
24 Nov 1914 · 111 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.