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Sensitivity of seismic wide‐angle wave‐field and first arrival times to fine scale crustal structure and moho topography
Author(s) -
Hansen Thomas M.,
Singh Satish C.,
Jacobsen Bo H.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900553
Subject(s) - geology , seismology , geodesy , moho , sensitivity (control systems) , inversion (geology) , geophysics , tectonics , engineering , electronic engineering , microbiology and biotechnology , biology , fungi imperfecti
A sensitivity study of stochastic crustal and Moho models on Moho refracted first arrivals is presented. The crustal model is a self‐affine velocity structure superposed on a linear velocity gradient. The Moho is represented by a first‐order discontinuity with a topography which is also self‐affine. The sensitivity of both travel‐time and wave‐field is considered. We found that the full wave‐field around the Pn arrival is sensitive to crustal structures down to 1 km, and to Moho undulations down to 5 km. However, the first arrivals are only sensitive to crustal structure down to about 3 km, and to Moho structure down to 10 km. Our analysis suggests that the wide‐angle full wave‐field has a sensitivity that is intermediate between the sensitivity of the vertically reflected wave‐field and wide‐angle arrival times. These findings give some justification to the mainstream ray tracing approach to wide‐angle data inversion, where resulting models incorporate only a moderate number of features at relatively large scales.