Earth Planets Space, Vol. 63 (No. 7), pp. 541-545, 2011
Jascha Polet1 and Hong Kie Thio2
1Department of Geological Sciences, California State Polytechnic University, Pomona, CA 91768
2URS Corporation, 915 Wilshire Blvd, suite 700, Los Angeles, CA 90017
(Received April 5, 2011; Revised May 2, 2011; Accepted May 7, 2011; Online published September 27, 2011)
We present the results of a near real-time determination of a Centroid Moment Tensor for the 2011 Tohoku quake and the subsequent rapid prediction of Pacific coast tsunami waveheights based on these CMT parameters. Initial manual CMT results for this event were obtained within 23 minutes of origin time and fully automatic results were distributed by E-mail within 33 minutes. The mechanism, depth and moment magnitude were all well constrained, as was indicated by a bootstrapping analysis. Using an existing library of tsunami Green's functions, we computed predicted waveheights in the north Pacific for several scenarios of the Tohoku earthquake that are consistent with the CMT solution. Overall, these predicted waveheights correspond well with preliminary observations around the Pacific Rim. The predictions for North America were sent out three and a half hours after the origin time of the earthquake, but this system has the potential to provide these predictions within minutes after receiving the CMT solution.
Key words: Real-time earthquake source analysis, tsunami early warning, 2011 Tohoku earthquake, Centroid Moment Tensor.