GRAVITY-ANOMALY FROM FAULTING ON A LAYERED SPHERICAL EARTH WITH APPLICATION TO CENTRAL JAPAN

Authors
Citation
Ff. Pollitz, GRAVITY-ANOMALY FROM FAULTING ON A LAYERED SPHERICAL EARTH WITH APPLICATION TO CENTRAL JAPAN, Physics of the earth and planetary interiors, 99(3-4), 1997, pp. 259-271
Citations number
33
Categorie Soggetti
Geochemitry & Geophysics
ISSN journal
00319201
Volume
99
Issue
3-4
Year of publication
1997
Pages
259 - 271
Database
ISI
SICI code
0031-9201(1997)99:3-4<259:GFFOAL>2.0.ZU;2-H
Abstract
The gravity anomaly resulting from mass redistribution from an earthqu ake source (point dislocation) is re-explored in a spherical Earth geo metry. Using a previously developed method of determining the Green's functions for the static displacement field on a layered Earth, I obta in the corresponding Green's functions for the perturbed gravitational potential and gravity anomaly in a spherical harmonic expansion. The synthesized gravity anomaly includes the effects of changes in the int rinsic density distribution due to divergence of the displacement fiel d and vertical displacement along level surfaces in density (stratific ation displacement). Numerical examples of the Bouguer gravity anomaly produced on a layered crustal model show that the contribution of int rinsic density changes dominates over the contribution of stratificati on displacement. Application to central Japan yields a new image of a buried thrust structure suspected of having ruptured in the 1891 Nobi earthquake.