Two ML 5 earthquakes on Feb.6, 2002 in Anchorage
On February 06, 2002 two ML 5 events occurred in the Anchorage area. The second shock occured 45 sec after the first shock. They were felt strongly in the south-central Alaska. In addition to the AEIC data we used recordings from the Anchorage Strong Motion Project to locate the two shocks. The AEIC reviewed locations and magnitudes for the two shocks are:
2/06 17:18:45.692 61.1741N -149.7255W 36.74 km Ml 5.0
2/06 17:19:29.141 61.2017N -149.7001W 37.54 km Ml 5.0
These events occurred inside the subducting Pacific plate. The first motion focal mechanism is typical for events in this area and indicates down-dip extension. AEIC located 87 aftreshocks throughout the end of February. The largest afershock was ML 2.9 two hours after the M5 events. One event on Feb.8 (M 1.9) occurred in the overriding plate at 4.5 km depth above the source region of the M5 events.
Paz=172; Ppl=28; Taz=285; Tpl=36
strike1=315; dip1=42; rake1=173; strike2=50; dip2=85; rake2=48
The SE-NW oriented focal plane is consistent with the aftershock distribution.
The NEIC estimated mb of 5.0 and 5.1, for the eartlier and later shocks, respectively.
We are working on a moment tensor inversion of these events. Visit us later for the updates.
Locations of the two Anchorage M 5 events and their aftershocks
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webmaster@www.giseis.alaska.edu- February 16, 2002