During the first month following the mainshock, the Alaska Earthquake Center had located in excess of 1800 aftershocks with a magnitude of completeness of 2.5. More than 40 aftershocks were larger than M4, the largest being a M6.6 event in the overriding North American plate at a depth of 12 miles (19 km), which occurred about six hours after the mainshock at 7:15 pm (June 24, 3:15 UTC).

Hypocentral relocations done by Macpherson and Ruppert 2015 show that most aftershocks did not occur on the rupture plane, but are concentrated in the adjacent Wadati‐Benioff zone.

Relocated aftershocks and background seismicity are shown below for events with M>2 occurring between January 2006 and October 2014. Aftershocks from the M7.9 mainshock are shown in green in the cross sections.

Last Modified: April 19, 2024