Y. Fukuda et al., Crustal movements around the Beppu Bay area, East-Central Kyushu, Japan, observed by GPS 1996-1998, EARTH PL SP, 52(11), 2000, pp. 979-984
In order to detect the crustal movement in the Beppu Bay area, where the hi
ghest intra-plate strain rates in Japan is expected, precise GPS measuremen
ts have been repeatedly conducted since 1994 at one-year intervals. The res
ult shows N-S or NNE-SSE extension taking place at a rate of more than 10 m
m/yr around Beppu Bay. This is essentially consistent with the result obtai
ned by the geodetic survey conducted over the last 100 years, and it sugges
ts a constant rate of crustal motion over the period. The result gives a st
rong constraint for future modeling of the stress field recovery in the are
a. However, we failed to identify whether the movement occurred at any spec
ific fault. A denser array of GPS points is needed in the area, and especia
lly near the major faults, in order to investigate possible fault-related m
otion.