Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Teng, T.-l. Articles by Lee, W. H. K. Search for Related Content GeoRef GeoRef Citation

One minute after: Strong-motion map, effective epicenter, and effective magnitude

Department of Earth Sciences University of Southern California, Los Angeles, California
Central Weather Bureau, Taipei, Taiwan, ROC
Institute of Geophysics National Central University, Chungli, Taiwan ROC

Abstract

This article reports the recent progress on real-time seismic monitoring in Taiwan, particularly the real-time strong-motion monitoring by the Taiwan Central Weather Bureau's telemetered seismic network (CWBSN), which is presently aiming at rapid reporting immediately after a large earthquake occurrence. If rapid reporting can be achieved before the arrival of the strong shaking, earthquake early warning will become possible. CWBSN has achieved the generation of the intensity map, epicenter, and magnitude within 1 min of the occurrence of a large earthquake. Both rapid reporting and early warning are principally applied to large (M >> 5) events; the requirement of on-scale waveform recording prompted CWBSN in 1995 to integrate strong-motion sensors (e.g., force-balance accelerometers) into its telemetered seismic monitoring system. Time-domain recursive processing is applied to the multi-channel incoming seismic signals by a group of networked personal computers to generate the intensity map. From the isoseismal contours, an effective epicenter is immediately identified that resides in the middle of the largest (usually the 100-gal) contour curve of the intensity map. An effective magnitude is also defined that can be derived immediately from the surface area covered by the largest (usually the 100-gal) contour curve. For a large event with a finite rupture surface, the epicenter and magnitude so derived are more adequate estimates of the source location and of the strength of destruction. The effective epicenter gives the center of the damage area; it stands in contrast with the conventional epicenter location, which only gives the initial point of rupture nucleation. The effective magnitude reflects more closely the earthquake damage potential, instead of the classical magnitude definition that emphasizes the total energy release. The CWBSN has achieved in obtaining the above crucial source information well within 1 min. This time can further be reduced to better than 30 sec, as illustrated by the example in this article, showing that earthquake early warning is indeed an achievable goal. The rapid reporting and early warning information is electronically transmitted to users to allow rapid response actions, with or without further human intervention.

This article has been cited by other articles:

				Y.-M. Wu and H. Kanamori Rapid Assessment of Damage Potential of Earthquakes in Taiwan from the Beginning of P Waves Bulletin of the Seismological Society of America, June 1, 2005; 95(3): 1181 - 1185. [Abstract] [Full Text] [PDF]

				S. Horiuchi, H. Negishi, K. Abe, A. Kamimura, and Y. Fujinawa An Automatic Processing System for Broadcasting Earthquake Alarms Bulletin of the Seismological Society of America, April 1, 2005; 95(2): 708 - 718. [Abstract] [Full Text] [PDF]

				Y.-M. Wu and H. Kanamori Experiment on an Onsite Early Warning Method for the Taiwan Early Warning System Bulletin of the Seismological Society of America, February 1, 2005; 95(1): 347 - 353. [Full Text] [PDF]

				An Overview of the 1999 Chi-Chi, Taiwan, Earthquake Bulletin of the Seismological Society of America, October 1, 2004; 91(5): 895 - 913.

				Spatial and Temporal Distribution of Slip for the 1999 Chi-Chi, Taiwan, Earthquake Bulletin of the Seismological Society of America, October 1, 2004; 91(5): 1069 - 1087.

				Near Real-Time Mapping of Peak Ground Acceleration and Peak Ground Velocity Following a Strong Earthquake Bulletin of the Seismological Society of America, October 1, 2004; 91(5): 1218 - 1228.

				Seismic Attenuation and Peak Ground Acceleration in Taiwan Bulletin of the Seismological Society of America, October 1, 2004; 91(5): 1229 - 1246.

				Source Modeling Using Strong-Motion Waveforms: Toward Automated Determination of Earthquake Fault Planes and Moment-Release Distributions Bulletin of the Seismological Society of America, April 1, 2003; 93(2): 639 - 654.

				Relationship between Peak Ground Acceleration, Peak Ground Velocity, and Intensity in Taiwan Bulletin of the Seismological Society of America, February 1, 2003; 93(1): 386 - 396.

				A Virtual Subnetwork Approach to Earthquake Early Warning Bulletin of the Seismological Society of America, June 1, 2002; 92(5): 2008 - 2018.

				Y.-M. Wu, T.-C. Shin, and Y.-B. Tsai Quick and reliable determination of magnitude for seismic early warning Bulletin of the Seismological Society of America, October 1, 1998; 88(5): 1254 - 1259. [Abstract] [PDF]