Spatial variations in present‐day deformation, Kenai Peninsula, Alaska, and their implications

Abstract

Abstract. From four years of Global Positioning System (GPS) measurementsWe interpret the trenchward velocities as being caused by a continuing postseismic transient from the 1964 great Alaska earthquake. There may be significant along-strike differences in the long-term behavior of the plate interface between the western and eastern Kenai, based on roughly coincident boundaries in the coseismic slip distribution, cumulative postseismic uplift, present-day plate coupling, and stress field. The present postseismic response appears to generate purely trenchward motion, suggesting a creep process that is purely dip slip. Our observations suggest that postseismic processes after the largest earthquakes can influence patterns of deformation for decades after the event.

Mountain Building: From Earthquakes to Geologic Deformation

“…It thus appears that, in the Himalayan context, interseismic coupling varies essentially along the downdip direction. The homogeneous pattern of coupling along the MHT is very different from the strongly heterogeneous coupling observed on subduction megathrust characterized by both downdip and along-strike variations (Chlieh et al, 2008;Freymueller et al, 2000;Loveless and Meade, 2010;Moreno et al, 2010;Suwa et al, 2006;Wallace et al, 2004). Temperature, pressure, metamorphic grade, and fluid contents are all factors that vary primarily along the downdip direction and that play a key role in controlling downdip variations of interseismic coupling along the MHT.…”

Late Quaternary uplift rate of the northeastern Japan arc inferred from fluvial terraces

“…This long-term uplift rate (implied by the incision rate) is one order of magnitude smaller than the short-term uplift rate (Pazzaglia and Brandon, 2001) probably because the long-term uplift does not include an earthquake cycle elastic deformation, given that the Cascadia subduction thrust is locked (Fleymuller et al, 2000). In the Cascadia subduction zone (a sedimentaccretion-dominant zone), the long-term forearc uplift is interpreted to be driven by both accretion and withinwedge deformation (Brandon et al, 1998).…”

Volcanic and tectonic deformation on Unimak Island in the Aleutian Arc, Alaska

“…Daily solutions were transformed to the ITRF97 reference frame [ Boucher et al , 1999], and combined to estimate site velocities. Details of our analysis methods are given by Freymueller et al [1999, 2000]. To obtain velocities relative to the North American plate (NOAM), we used the pole and rotation for the ITRF97‐NOAM relative motion given by Sella et al [2002].…”