The Alaska Earthquake Center reports a magnitue 5.1 earthquake hit southcentral Alaska at a depth of 54.9 miles at 10:59 a.m. on Saturday, March 12. The earthquake hit 23 miles west of Nikiski with neighboring communities of Kenai, Tyonek, Soldotna, Kasilof, and Clam Gulch feeling the rumble in addition to Redoubt Volcano and Mt. Spurr. In the immediate 20-30 mile radius, the earthquake lasted for about 12-14 seconds.
The Earthquake Center states that earthquakes in Southern Alaska are produced by several different tectonic features, the strongest of which are generated by the megathrust fault that marks the contact zone between the subducting Pacific and overriding North American plates.
The 1964 M9.2 Great Alaska Earthquake, which is still the second largest earthquake ever recorded worldwide began under Prince William Sound. Historically, magnitude 6+ earthquakes of this type have been recorded beneath Cook Inlet. The crustal seismicity in the region can be attributed to the faults and folds of the Cook Inlet basin, the Castle Mountain Fault, and the wind band of diffuse seismicity extending from northern Cook Inlet to the Denali Fault. The April 1933 M6.9 earthquake near Anchorage appears to have occurred on such a structure.
The National Weather Service states that a tsunami is NOT expected.