Magnitude determination using duration of high frequency energy radiation and displacement amplitude: application to tsunami earthquakes

Tatsuhiko Hara

doi:10.1186/bf03352718

Abstract

Abstract Recently, we developed a new method to determine earthquake magnitudes using durations of high frequency energy radiation and the maximum displacement amplitudes, which can be measured from processing of first arriving P-waves. In the present study, we applied this method to the 1992 Nicaragua, 1994 Java, 1996 Peru, and 2006 Java earthquakes which have been suggested to be “tsunami earthquakes.” Our magnitude estimates for these earthquakes are consistent with the moment magnitudes in the Global CMT catalog, which demonstrates that our method is applicable to tsunami earthquakes. The analyzed tsunami earthquakes are characterized in our method as those with longer source durations and smaller displacement amplitudes.

Highlights

Rapid magnitude determination is essential for tsunami warnings
Magnitudes are determined using durations of high frequency energy radiation and the maximum displacement amplitudes measured from first arriving P-waves recorded at tele-seismic
We showed that this method was applicable to shallow large (Mw≥7.2) earthquakes including the 2004 Sumatra earthquake, and that this method would be effective for rapid magnitude determination for tele-seismic events

Summary

Introduction

Rapid magnitude determination is essential for tsunami warnings. The recent two large tsunamigenic earthquakes, the December 26, 2004 Sumatra (Mw 9.0) and the July 17, 2006 Java (Mw 7.7) earthquakes, have shown that rapid magnitude determination still needs further improvements. Magnitudes are determined using durations of high frequency energy radiation and the maximum displacement amplitudes measured from first arriving P-waves recorded at tele-seismic T. HARA: MAGNITUDE DETERMINATION OF TSUNAMI EARTHQUAKES

Results

Conclusion