TITLE:
Current State of Strain in the Central Cascadia Margin Derived from Changes in Distance between GPS Stations
AUTHORS:
Kenneth M. Cruikshank, Curt D. Peterson
KEYWORDS:
Convergent Margin, Cascadia, Strain, Strain-Energy, GPS
JOURNAL NAME:
Open Journal of Earthquake Research,
Vol.4 No.1,
February
17,
2015
ABSTRACT: Using continuously operating Global Positioning Stations in the Pacific Northwest of the United States, over 100 station-station baseline length changes were determined along seven West-East transects, two North-South transects and in three localized areas to determine both the average annual strains over the past several years, and the variation in strain over the central Cascadia convergent margin. The North-South transects (composed of multiple baselines) show shortening. Along West-East transects some baselines show shortening and others extension. The direction of the principle strains calculated for two areas 100 km from the deformation front are close to per-pendicular to the deformation front. The North-South strains are 10?8 a?1, which is an order-of-magnitude less than the West-East strains (10?7 a?1). Along several West-East transects, the magnitude of the strain increases away from the deformation front. All West-East transects showed a change in strain 250 km inland from deformation front.