3.12 Amchitka section
The Amchitka section (Figure 6) extends ~325 km from
Amchitka Pass to Murray Canyon and encompasses the eastern portion of
the Mw 8.7 1965 Rat Islands rupture, as well as the area
of the much smaller 2003 Mw 7.8 earthquake (Figure 1).
The Amchitka section corresponds to the hypothesized Rat structural
block of (Geist et al., 1988) and one of three asperities in the 1965
event proposed by Beck & Christensen (1991).
Geodetic observations in the Amchitka section are sparse (Cross &
Freymueller, 2008) and no direct coupling model is available. Based on
the neighboring Attu section, we infer 50% coupling over an area
roughly the same as the Attu section, extending ~115 km
arcward from the deformation front to approximately 40 km interface
depth (Figure 6).