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A New Trigger Criterion for Improved Real-Time Performance of Onsite Earthquake Early Warning in Southern California

Böse, M. and Hauksson, E. and Solanki, K. and Kanamori, H. and Wu, Y.-M. and Heaton, T. H. (2009) A New Trigger Criterion for Improved Real-Time Performance of Onsite Earthquake Early Warning in Southern California. Bulletin of the Seismological Society of America, 99 (2a). pp. 897-905. ISSN 0037-1106. doi:10.1785/0120080034.

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We have implemented and tested an algorithm for onsite earthquake early warning (EEW) in California using the infrastructure of the Southern California Seismic Network (SCSN). The algorithm relies on two parameters derived from the initial 3 sec of P waveform data at a single seismic sensor: period parameter τ_c and high-pass filtered displacement amplitude P_d. Previous studies have determined empirical relationships between c and the moment magnitude M_w of an earthquake, and between P_d and the peak ground velocity (PGV) at the site of observation. In 2007, seven local earthquakes in southern California with 4.0≤M_L≤4.7 have triggered the calculation of M_w and PGV by the EEW algorithm. While the mean values of estimated parameters were in the expected range, the scatter was large, in particular for the smallest events. During the same time period the EEW algorithm produced a large number of false triggers due to low trigger thresholds. To improve the real-time performance of the onsite approach, we have developed a new trigger criterion that is based on combinations of observed τ _c and P_d values. This new criterion removes 97% of previous false triggers and leads to a significant reduction of the scatter in magnitude estimates for small earthquakes.

Item Type:Article
Related URLs:
URLURL TypeDescription
Hauksson, E.0000-0002-6834-5051
Kanamori, H.0000-0001-8219-9428
Heaton, T. H.0000-0003-3363-2197
Additional Information:© 2009 Seismological Society of America. This work is funded through Contract Number 06HQAG0149 from USGS/ANSS to the California Institute of Technology (Caltech). The Southern California Seismic Network (SCSN) and the Southern California Earthquake Data Center (SCEDC) are funded through contracts with USGS/ANSS, the California Office of Emergency Services (OES), and the Southern California Earthquake Center (SCEC). This is Contribution Number 10000 of the SeismoLab, Geological and Planetary Sciences at Caltech.
Group:Seismological Laboratory, Division of Geological and Planetary Sciences
Funding AgencyGrant Number
California Office of Emergency ServicesUNSPECIFIED
Southern California Earthquake Center (SCEC)UNSPECIFIED
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Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences10000
Issue or Number:2a
Record Number:CaltechAUTHORS:20090807-071209164
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14861
Deposited By: Ruth Sustaita
Deposited On:01 Sep 2009 22:59
Last Modified:08 Nov 2021 23:14

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