This project involves studies of global and regional seismicity. Central to the project is a continuation of the Harvard Centroid-Moment-Tensor (CMT) Project, which now represents a 22-year-long effort to analyze global earthquake activity and to maintain a comprehensive and authoritative catalog of earthquake focal mechanisms, the CMT Catalog. In addition to the systematic analysis and of earthquakes and dissemination of earthquake information, the research also includes the development of a dynamic earthquake moment-tensor database. The new catalog will be searchable on the web, and will include auxiliary data, such as information about the seismograms and Earth model used in the analysis, the quality of the solution, and any history of updates to the results. A second component of the project is an examination of previously undetected earthquakes. More than 1,800 events with magnitudes greater than 4.7 have recently been found using a new detection algorithm, and a substantial subset of these are clearly not common earthquakes. The effort will involve a first-order, systematic analysis of the new events to determine why they eluded earlier detection (e.g., whether all of the events lack high-frequency radiation and are thus slow earthquakes) and the specific tectonic (or non-tectonic) explanations for several specific groups of detections, including (1) events associated with volcanic eruptions or collapses; (2) events associated with glaciers in Alaska, Antarctica, and Greenland; and (3) events off the coast of North Carolina, possibly associated with submarine slumping.
