Abstract
We use a Global Positioning System (GPS)-derived surface velocity field of Taiwan for the time period between 1993 and 1999 to infer interseismic slip rates on subsurface faults. We adopt a composite elastic half-space dislocation model constrained by the observed horizontal velocities projected into the direction of plate motion (306°). The GPS data are divided into northern and southern regions and the velocities in each region are projected into single profiles. The model fault geometry includes a shallowly dipping décollement, based on the balanced geological cross-sections in the Coastal Plain and Western Foothills, and a two-segment fault representing the Longitudinal Valley Fault (LVF) in eastern Taiwan. The décollement is composed of two fault segments, one extending west under the Central Range (CR) and one extending east of the LVF, with estimated slip rates of about 35 and 80 mm/yr, respectively. The optimal geometry of décollement is subhorizontal (2°∼11°) at a depth of 8∼9 km. The inferred surface location of the western end point of dislocation in the northern profile is located 15 km east of the Chelungpu Fault, while in the southern section, it is located beneath the Chukou Fault. The elastic dislocation model successfully matches the horizontal velocity data, and predicts elastic strain accumulation in the Western Foothills that will presumably be released in future earthquakes. However, considered over multiple earthquake cycles, our model cannot explain the topography of the CR and thus fails to predict the active mountain building process in Taiwan. This failure indicates that both horizontal and vertical velocity fields require a more complex rheological model that incorporates inelastic behavior.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.