Three-dimensional viscoelastic interseismic deformation model for the Cascadia subduction zone

• DOI: 10.1186/bf03352386
• Publication Date: 2014-08-15T03:15:03Z
• Authors: Kelin Wang; Jiangheng He; Herb Dragert; Thomas S. James
• Keywords: Forearc; Slab

Contemporary deformation of the Cascadia forearc consists an elastic interseismic strain build-up as part subduction earthquake "cycle" anda secular primarily in form ofarc-parallel translation and clockwise rotationofforearc blocks. Athree-dimensional (3-D) dislocation model, constrainedby vertical data, was developed previously to study deformation. In this study, we develop a 3-D viscoelastic finite element model for zone temporal spatial variations deformation, compare results with horizontal geodetic observations. The has lithosphere/slab mantle which viscosity 1019 Pa s constrained by recent postglacial rebound analyses. For comparison, adopt seismogenic geometry that used previous test effects different estimates relative plate motion on predictions. Interseismic is simulated assigning backslip rate locked fault, preceded rupture same zone. Based preliminary results, draw following conclusions: (1) decreases through period. A seaward predicted inland sites early period, effect postseismic creep mantle. (2) Model rates 300 years after are consistent observed values, regardless models used. velocities northern decrease landward at slower than providing better fit (3) Oblique causes partitioning. As result, direction local maximum contraction much less oblique convergence. northerly GPS southern represent northward forearc. may be partially accommodated cycles, but it modeled process independent cycle.