Reviewed by USGSAlaska100y ago
M6.2 earthquake 74 km SE of Perryville, Alaska
Saturday, August 6, 1927, 00:14:03 UTC · 55.378°N, 158.418°W
A magnitude 6.2 earthquake struck 74 km SE of Perryville, Alaska on Saturday, August 6, 1927, 00:14:03 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M6.2 on March 25, 1927.
- Magnitude
- 6.2
- Strong · mw
- Depth
- 35 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 earthquake
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
141 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: shallow
35 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 has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 15 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 102 km SW of this epicenter
- 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 115 km NE of this epicenter
- 6.873 km SW of Sand Point, AlaskaJuly 2, 1922 · 189 km W of this epicenter
- 6.5Bristol Bay, AlaskaAugust 22, 1907 · 241 km NW of this epicenter
- 6.4101 km SSW of Sand Point, AlaskaJuly 25, 1917 · 197 km SW of this epicenter
- 6.3298 km SSE of Sand Point, AlaskaJune 4, 1917 · 275 km S of this epicenter
- 6.2143 km SE of Perryville, AlaskaMarch 25, 1927 · 68 km SE of this epicenter
- 6.264 km SSE of Perryville, AlaskaJuly 28, 1927 · 19 km W 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. The most severe:
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 169 km away
tsunami
- 1868
Alaska Peninsula
15 May 1868 · 169 km away
tsunami
- 1880
Alaska Peninsula
29 Sep 1880 · 183 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.