An earthquake measuring 3.88 occurred 6 miles west-north-west of Aniak in the early morning hours on March 6th. The quake occurred at 4:51 am and several Aniak residents said they felt it.
You can see from the following photo that earthquakes are not common in this part of the state compared to central portion – but they do happen with some being substanitally stronger than the one today. An earthquake approaching 7.0 occurred in 1903 and one measuring 6.1 occurred in 1990 – both west of Crooked Creek along either the Iditarod-Nixon or the Thompson Creek Faults.
A 5.8 quake occurred near Sleetmute in 1971 and one measuring 5.4 occurred in 1989 in the vicinity of the Tatlawiksuk River.
The above map is from Geology of Soutwestern AK http://126.96.36.199/webpubs/outside/text/dnag_ch09.pdf