[The prompt report of the research[
<Shimabara Earthquake and Volcano observatory>
17:31 on March 26,1997 (M6.3)
04:33 on April 3,1997 (M5.5)
14:38 on May 13,1997 (M6.2)
The earthquake mechanism of the main shock (Kagoshima University, the University of Tokyo, Kochi University, and Meteorological Agency data are included.)
Projection of the lower hemisphere and black circles are pushes and white circles are pulls.
The nodal plane of east-and-west strike is mostly presumed to be the fault surface from the lateral fault of northeast-southwest compression and northwestern-southeast tension, and the aftershock distribution having a spread in east and west, as for the earthquake mechanism of this earthquake.
Record of the displacement waveform of Goto and Fukue observing points, and the broadband seismograph (STS-2). It is presumed that the main shock consists of two sub events.
<Corrected value April 2,1997>
Seismic moment Mo = 1.3 * 10**18 Nm
Moment magnitude Mw = 6.0
Fault S = 12 * 6 Km**2
Stress drop 5.3 MPa
Dislocation D = 70 cm
Epicentral distribution (the main shock is red circle)