Earthquake magnitude scaling using seismogeodetic data

Brendan W. Crowell, Diego Melgar, Yehuda Bock, Jennifer S. Haase, & Jianghui Geng

Published December 2013, SCEC Contribution #1932

The combination of GPS and strong-motion data to estimate seismogeodetic waveforms creates a data set that is sensitive to the entire spectrum of ground displacement and the full extent of coseismic slip. In this study we derive earthquake magnitude scaling relationships using seismogeodetic observations of either P wave amplitude or peak ground displacements from five earthquakes in Japan and California ranging in magnitude from 5.3 to 9.0. The addition of the low frequency component allows rapid distinction of earthquake size for large magnitude events with a precision of 0.4 Mw units, unlike accelerometer data that saturate for earthquakes greater than M 7 to 8, and is available well before the coseismic displacements are emplaced. These results, though based on a limited seismogeodetic data set, support earlier studies that propose it may be possible to estimate the final magnitude of an earthquake well before the rupture is complete.

Citation
Crowell, B. W., Melgar, D., Bock, Y., Haase, J. S., & Geng, J. (2013). Earthquake magnitude scaling using seismogeodetic data. Geophysical Research Letters, 40(23), 6089-6094. doi: 10.1002/2013GL058391.