Five Years after the 2002 Denali Fault Earthquake Sequence: A Regional Network Operator's Perspective

Abstract

We have passed the fifth anniversary of the 2002 Denali fault, Alaska, earthquake sequence. At this point it is worthwhile to look back and reflect on our experience with the event at the Alaska Earthquake Information Center (AEIC). The earthquake sequence started with the magnitude 6.7 earthquake on 23 October 2002. While no surface rupture was found during the aerial survey of the epicentral area, it very quickly became clear that this earthquake ruptured one of the most significant tectonic features in Alaska, the Denali fault (figure 1). While this event was widely felt throughout central Alaska, it did not cause significant damage. Following this event, AEIC installed a network of temporary seismometers to monitor the aftershock activity. This was a fortuitous action because a much larger earthquake, of magnitude 7.9, initiated just east of the mag nitude 6.7 event 10 days later on 3 November 2002. The temporary instruments provided valuable near-field recordings of the mainshock and of the early aftershocks. ▴ Figure 1. Recorded earthquakes (depth < 30 km) in the vicinity of the 2002 Denali fault earthquake sequence that occurred between …