An earthquake occurred at 8:43 AM Japanese Standard
Time on June 14,2008. Its epicenter was close to the border
of Iwate and Miyagi Prefectures. As the damage caused by
this earthquake was so severe, the Japan Meteorological Agency (JMA) named this event ‘‘The Iwate–Miyagi Nairiku
Earthquake of 2008’’. JMA assigned a magnitude of 7.2 to
this earthquake. This is the largest magnitude among inland
earthquake so fthis decade in Japan. JMA estimated its
epicenter as 39101.70 in latitude and 140152.80 in longitude.
The depth of the hypocenter was 8 km.
The fault plane analyzed by JMA is displayed in Fig. 1
along with the epicenter. It shows that this was a reverse
fault type of earthquake. The crust deformation estimated by
GPS and the distribution of after shocks indicate that the
actual fault plane dipped to the west. The rupture processes
studied by several researchers almost coincide. The epicenter
was located in the center of the fault plane, but the main
rapture occurred along the southern part of the fault. The
moment magnitudes deduced from the researchers’ work
were almost the same, namely, from 6.7 to 6.9.