The April 23, 1968 earthquake

M6.6near Halibut Cove, Alaska

A magnitude 6.6 earthquake 11.7 miles deep, 49.2 miles off Kenai Peninsula Borough. The 145th strongest in Alaska’s record since 1900, and the strongest within 50 miles in the catalogue, which runs from 1900.

The earthquake

Magnitude: 6.6; moment magnitude (mw)
Depth: 11.7 mi; 18.8 km below the surface
Local time: Tuesday, April 23, 1968; 10:29 AHST; 20:29 UTC
Epicentre: 58.65°N, 150.08°W; 49.2 mi from Kenai Peninsula Borough
In Alaska’s record: 145th; strongest of 124,625 since 1900
Within 50 miles: 1; county; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event iscgem824251 (“124 km SSE of Halibut Cove, 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

Kenai Peninsula BoroughAK · 49.2 mi

Earthquakes around the epicentre

130 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

August 24, 1964M5.8
September 6, 1964M5.7
April 2, 1964M5.7
March 27, 1964M5.7
March 28, 1964M5.6
April 9, 1964M5.5
March 29, 1964M5.5
May 28, 1964M5.5
June 28, 1964M5.5

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