A Mw7 earthquake occurred on December 6, 1999 at 2:12 pm AKST in the Kodiak Island region of Alaska. Aftershocks of M5.4 and M6.4 followed the mainshock by ten minutes and one hour, respectively. It appears that the main shock triggered a swarm of earthquakes in the Katmai volcano field that subsided in a few hours (Power et al., 2000).

Three magnitude 5.0-5.2 earthquakes occurred within the aftershock zone of the December, 1999 Mw7 earthquake between January and May, 2000.

On July 11, 2000, a Mw6.5 earthquake occurred in the aftershock zone of the Mw7 earthquake. Thirty aftershocks were located in the first five days following this earthquake, including a M5.5 event on July 11.

On January 10, 2001, another strong earthquake (Mw6.9) occurred.