Shallow subsurface structure of the Wasatch fault, Provo segment, Utah, from integrated compressional and shear-wave seismic reflection profiles with implications for fault structure and development

摘要: Integrated vibroseis compressional and experimental hammer-source, shear-wave, seismic reflection profiles across the Provo segment of Wasatch fault zone in Utah reveal near-surface shallow bedrock structures caused by geologically recent deformation. Combining information from surveys, geologic mapping, terrain analysis, previous first-arrival modeling provides a well-constrained cross section upper ∼500 m subsurface. Faults are mapped surface, through shallow, poorly consolidated deltaic sediments, cutting rigid surface. The new data used to test hypotheses on changing orientation with depth, number subsidiary faults within width zone, utility integrating separate elastic methods provide complex structural zone. Although surface mapping has indicated only few faults, shows wider more deformation both synthetic antithetic normal faults. Our study demonstrates usefulness combined deeper penetrating geophysical survey, integrated detailed constrain subsurface structure. Due complexity accurate velocity is essential was obtained first-break tomography model. constraints geometry can be refine estimates vertical versus lateral tectonic movements improve hazard assessment along an urban area. We suggest that earthquake-hazard assessments made without imaging may biased too