Reviewed by USGS80y ago
M6.1 earthquake in Mariana Islands region
Saturday, June 14, 1947, 16:30:08 UTC · 21.337°N, 145.790°E
A magnitude 6.1 earthquake struck in Mariana Islands region on Saturday, June 14, 1947, 16:30:08 UTC, at a depth of 20.0 km (shallow). It is the strongest earthquake within 300 km since an M6.6 on June 13, 1947.
- Magnitude
- 6.1
- Strong · mw
- Depth
- 20 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
24 kilotons of TNT
That is about 2 times the Hiroshima bomb. It released about 50 times the energy of a magnitude 5.0.
Tectonic setting
86 km
from the nearest mapped plate boundary, between the Mariana and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
20 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 M7.2 on June 19, 1947. 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 14 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.5Volcano Islands, Japan regionFebruary 24, 1934 · 269 km NW of this epicenter
- 7.2Mariana Islands regionJuly 11, 1905 · 198 km W of this epicenter
- 7.0Mariana Islands regionJune 13, 1947 · 59 km NW of this epicenter
- 6.6Mariana Islands regionJune 13, 1947 · 43 km N of this epicenter
- 6.4Mariana Islands regionAugust 27, 1919 · 40 km E of this epicenter
- 6.0Volcano Islands, Japan regionJanuary 12, 1920 · 271 km NW of this epicenter
- 6.0Mariana Islands regionMarch 15, 1946 · 246 km S of this epicenter
- 5.9Volcano Islands, Japan regionMarch 12, 1931 · 280 km NW 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 · 298 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.