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Challenges in Quantifying Small Earthquakes

Description: 

If properly done, systematic determination of regional moment tensors, RMT, has the potential of yielding a catalog of parameters that will be useful for studies of regional stress, ground motion, probabilistic seismic hazard and local magnitude calibration. The catalog is only useful if the procedure and data sets are documented. Lessons learned from manually processing more than 4000 regional moment tensors with Mw > 3 show that the confidence in a particular solution depends not only on waveform fit in a specified frequency band, but also on the regional velocity model used, compatibility with previous solutions in a region, e.g., regional context, and agreement with observed P-wave first motions. For archival purposes a solution must be accompanied by sufficient metadata so that the results can be duplicated. This recommendation applies not only to RMT but to other approaches to determining moment tensors. Illustrations of problems and differences will be presented for selected events to highlight the care required to produce a defendable catalog.

Session: Earthquake Source Parameters: Theory, Observations and Interpretations

Type: Oral

Date: 4/18/2023

Presentation Time: 10:00 AM (local time)

Presenting Author: Roebrt B. .. Herrmann

Student Presenter: No

Invited Presentation: Yes

Authors