Reviewed by USGSAlaska35y ago
M3.2 earthquake 6 km NNE of False Pass, Alaska
Saturday, June 15, 1991, 16:48:56 UTC · 54.904°N, 163.374°W
A magnitude 3.2 earthquake struck 6 km NNE of False Pass, Alaska on Saturday, June 15, 1991, 16:48:56 UTC, at a depth of 72.5 km (intermediate).
- Magnitude
- 3.2
- Minor · md
- Depth
- 73 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 earthquake
In context
How big was it, and why here?
Energy released
951 kg of TNT
That is about 1/15,825 of the Hiroshima bomb. A magnitude 5.0 releases about 501 times more energy.
Tectonic setting
180 km
from the nearest mapped plate boundary, between the North American and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: intermediate
73 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 50 km
USGS has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 202 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.6The 1946 Unimak Island, Alaska EarthquakeApril 1, 1946 · 161 km S of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 223 km E of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 146 km E of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 200 km SW of this epicenter
- 7.071 km SE of King Cove, AlaskaMay 30, 1991 · 120 km E of this epicenter
- 6.868 km SSW of Unalaska, AlaskaMarch 29, 1957 · 293 km SW of this epicenter
- 6.873 km SW of Sand Point, AlaskaJuly 2, 1922 · 138 km E of this epicenter
- 6.768 km SSE of King Cove, AlaskaApril 29, 1937 · 110 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 168 recorded deaths. The most severe:
- 1946M8.6
Unimak Island
1 Apr 1946 · 161 km away · intensity VI
168 deaths$26 million damagetsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 152 km away
tsunami
- 1948M7.5
Alaska Peninsula
14 May 1948 · 159 km away
- 1957M7.5
Aleutian Islands: Fox Islands
22 Mar 1957 · 117 km away · intensity V
- 1820
East Aleutian Islands
1 Mar 1820 · 92 km away
tsunami
- 1868
Alaska Peninsula
15 May 1868 · 152 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.