Pr. Cummins et al., REFINED COSEISMIC DISPLACEMENT MODELING FOR THE 1994 SHIKOTAN AND SANRIKU-OKI EARTHQUAKES, Geophysical research letters, 25(17), 1998, pp. 3219-3222
We consider refined modeling of GPS measurements of coseismic displace
ment for two large earthquakes occurring in the Japan and Kurile Trenc
hes. Calculations are performed for a layered sphere and the homogeneo
us half-space more commonly used to model such data, using fault geome
try and slip distributions from previously published studies. We show
that the difference between the layered sphere and homogeneous half-sp
ace calculations can be significant, as expected from previous theoret
ical studies. However, it does not appear large enough to seriously af
fect results from previously published studies of these earthquakes. N
evertheless, the fact that the effects of sphericity and especially la
yering are measurable in coseismic observations of great earthquakes a
t moderate distances indicates that these effects should be taken into
account in order to fully exploit the precision of modern GPS measure
ments.