Off the West Coast of Northern Sumatra Earthquake (Mw 9.0)




The mainshock (00h58m, Dec. 26, 2004, Mw9.0) and its aftershocks of off the west coast of northern Sumatra earthquake until 20h11m, Dec. 27, 2004 were relocated by the modified joint hypocenter determination (MJHD) method. P-wave arrival times fifty at one stations reported by the US Geological Survey were used in relocation. The length and width of the aftershock area are 1,300km and 200km, respectively. Note that real errors of focal depths are much larger than standard errors shown by crosses.



Fig. 1 Left: Relocated earthquakes. Right: USGS location. The Harvard CMT solution for the mainshock is also shown.


Fig. 2. Stations used in relocation. The epicenter of the mainshock is shown by the asterisk.


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