One of the missions of the USGS NEIC is to rapidly determine the location and size of all destructive earthquakes worldwide and to immediately disseminate this information to concerned national and international agencies, scientists, and the general public.

The rCMT (research CMT) system computes fully automated Centroid Moment Tensors (CMTs) for large worldwide earthquakes using long period surface waves and is currently operational at the National Earthquake Information Center (NEIC) of the United States Geological Survey (USGS) in research/evaluation mode. 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. Overall, these predicted waveheights correspond well with preliminary observations around the Pacific Rim. 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.

The mechanism, depth and moment magnitude were all well constrained, as was indicated by a bootstrapping analysis. 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. 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.

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