Earthquake magnitude calculation without saturation from the scaling of peak ground displacement
Crowell, Brendan W.
Allen, Richard M.
Hill, Emma Mary
Date of Issue2015
Earth Observatory of Singapore
GPS instruments are noninertial and directly measure displacements with respect to a global reference frame, while inertial sensors are affected by systematic offsets—primarily tilting—that adversely impact integration to displacement. We study the magnitude scaling properties of peak ground displacement (PGD) from high-rate GPS networks at near-source to regional distances (~10–1000 km), from earthquakes between Mw6 and 9. We conclude that real-time GPS seismic waveforms can be used to rapidly determine magnitude, typically within the first minute of rupture initiation and in many cases before the rupture is complete. While slower than earthquake early warning methods that rely on the first few seconds of P wave arrival, our approach does not suffer from the saturation effects experienced with seismic sensors at large magnitudes. Rapid magnitude estimation is useful for generating rapid earthquake source models, tsunami prediction, and ground motion studies that require accurate information on long-period displacements.
Geophysical Research Letters
© 2015 American Geophysical Union (AGU). This paper was published in Geophysical Research Letters and is made available as an electronic reprint (preprint) with permission of American Geophysical Union (AGU). The published version is available at: [http://dx.doi.org/10.1002/2015GL064278]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.