Open AccessSurface coseismic gravity changes caused by dislocations in a 3‐D heterogeneous earth
Author(s) -
Fu Guangyu,
Sun Wenke
Publication year - 2008
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2007.03684.x
Subject(s) - perpendicular , geology , geodesy , slip (aerodynamics) , dislocation , seismology , geometry , computation , position (finance) , geophysics , physics , mathematics , condensed matter physics , finance , algorithm , economics , thermodynamics
SUMMARY This study describes an examination of surface gravity changes caused by dislocations within a 3‐D heterogeneous earth. This new theory is described using six independent dislocations: a vertical strike‐slip, two vertical dip‐slips perpendicular to each other, and three tensile openings on three perpendicular planes. A combination of the six independent dislocations is useful to compute coseismic gravity changes resulting from an arbitrary seismic source at an arbitrary position. Based on the 3‐D lateral inhomogeneous P ‐wave velocity model, we deduce the 3‐D density and S ‐wave velocity models using the relation of Karato. Finally, numerical computations are performed for a location south of Japan (30°N, 135°E). We calculate the coseismic gravity changes resulting from the six independent dislocations for source depths of 100, 300 and 637 km, respectively. Numerical results show that the maximum 3‐D effect varies concomitantly with the dislocation type and the source depth. For seismic problems, the effect of elastic parameter μ is dominant.