Focal Mechanism of the Earthquake under Suruga Bay on August 11
The focal mechanism of the earthquake under Suruga Bay on August 11 (M6.5) shows a reverse fault with a strike-slip component and a compression axis in a NNE-SSW direction, for both the P wave and CMT analyses. In P wave mechanism analyses of aftershocks, mechanisms are distributed between reverse faults and the strike-slip faults (Figure 4). For P-axis directions of aftershocks, the direction similar to that of the main shock is prominent (Figure 5).
Figure 1: Locations of Focal Mechanisms (Black dots are events that occurred after October 2002 at a depth of shallower than 60km. M≥1.0)
Figure 2: E-W Cross Section for Area a in Figure 1
Figure 3: Focal Mechanisms of the Main Shock (Left: P wave analysis, Right: CMT analysis)
Figure 4: Triangle Diagram of the Main Shock and Aftershocks focal mechanisms (The star is the main shock.)
Figure 5: Rose Diagrams of P-Axis, T-Axis and N-Axis of the Aftershock Focal Mechanisms (Red triangles show the main shock axes.)
Japan Meteorological Agency
[Seismic Activity under the Suruga Bay on August 11, 2009 (September 10, 2009)]