The March 11, 1957 earthquake

M6.5near Atka, Alaska

A magnitude 6.5 earthquake 15.5 miles deep, 30.3 miles off Aleutians West Census Area. The 185th strongest in Alaska’s record since 1900, and the strongest within 50 miles since a magnitude 6.6 on March 9, 1957.

The earthquake

Magnitude: 6.5; moment magnitude (mw)
Depth: 15.5 mi; 25.0 km below the surface
Local time: Monday, March 11, 1957; 20:28 NST; 07:28 UTC on Mar 12, 1957
Epicentre: 51.59°N, 173.59°W; 30.3 mi from Aleutians West Census Area
In Alaska’s record: 185th; strongest of 124,625 since 1900
Within 50 miles: 1; county; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event iscgem886116 (“79 km SSE of Atka, Alaska”). The USGS event page carries the ShakeMap, felt reports and the official summary.

Counties and cities within 50 miles

Distance from the epicentre to each county boundary (zero when inside) and to each city centre.

Counties

Aleutians West Census AreaAK · 30.3 mi

Earthquakes around the epicentre

1,944 earthquakes of magnitude 3 or more within 50 miles of this epicentre since 1973.

Earlier earthquakes of magnitude 5 or more within 50 miles, strongest first

November 1, 1946M6.8
March 9, 1957M6.6
March 9, 1957M6.6
March 10, 1957M6.5
May 1, 1933M6.1
July 19, 1933M6.1
July 19, 1933M6.1
March 10, 1957M6.0
July 18, 1933M6.0
January 14, 1956M6.0

USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.