3.4 Barren Islands section
The Barren Islands section (Figure 3) is the narrowest section we define along strike (~95 km), and this stretch of the subduction interface appears to have slipped very little in 1964 (Ichinose et al., 2007; Suito & Freymueller, 2009) and is poorly coupled from geodetic observations (Freymueller et al., 2000); (Suito & Freymueller, 2009) (Li et al., 2016). Ye et al. (1997) interpret a 20-km-thick underplated low-velocity zone along the Barren Islands section, and von Huene et al. (1999) infer that the 58° fracture zone may modulate rupture here and in the adjoining Kenai section.
No paleoseismic data from the Barren Islands section are available. We infer that this section ruptures with neighboring sections, as in 1964, and that geologic recurrence is similar to the neighboring Kenai section (closed-interval mean recurrence of ~441 years) (Table 1). Geodetic data are interpreted as consistent with a relatively small (~95 x ~75 km) near-trench patch with 50% coupling (Figure 3), and this section is differentiated in our model because of this coupling difference and the relative lack of slip in 1964.