An Earthquake Early Warning Algorithm Based on the P‐Wave Energy Released in the tS–tP Interval

Research Article| December 19, 2017 An Earthquake Early Warning Algorithm Based on the P‐Wave Energy Released in the tS–tP Interval Armando Cuéllar; Armando Cuéllar aCentro de Instrumentación y Registro Sísmico (CIRES), Anaxagoras 814, Colonia Narvarte, Mexico City, Mexico 03020, cuellara@cires.org.mxespinosajm@cires.org.mx Search for other works by this author on: GSW Google Scholar Gerardo Suárez; Gerardo Suárez bInstituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, Mexico 04510, gerardo@geofisica.unam.mx Search for other works by this author on: GSW Google Scholar J. M. Espinosa‐Aranda J. M. Espinosa‐Aranda aCentro de Instrumentación y Registro Sísmico (CIRES), Anaxagoras 814, Colonia Narvarte, Mexico City, Mexico 03020, cuellara@cires.org.mxespinosajm@cires.org.mx Search for other works by this author on: GSW Google Scholar Author and Article Information Armando Cuéllar aCentro de Instrumentación y Registro Sísmico (CIRES), Anaxagoras 814, Colonia Narvarte, Mexico City, Mexico 03020, cuellara@cires.org.mxespinosajm@cires.org.mx Gerardo Suárez bInstituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, Mexico 04510, gerardo@geofisica.unam.mx J. M. Espinosa‐Aranda aCentro de Instrumentación y Registro Sísmico (CIRES), Anaxagoras 814, Colonia Narvarte, Mexico City, Mexico 03020, cuellara@cires.org.mxespinosajm@cires.org.mx Publisher: Seismological Society of America First Online: 19 Dec 2017 Online Issn: 1943-3573 Print Issn: 0037-1106 © Seismological Society of America Bulletin of the Seismological Society of America (2018) 108 (1): 238–247. https://doi.org/10.1785/0120170115 Article history First Online: 19 Dec 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Armando Cuéllar, Gerardo Suárez, J. M. Espinosa‐Aranda; An Earthquake Early Warning Algorithm Based on the P‐Wave Energy Released in the tS–tP Interval. Bulletin of the Seismological Society of America 2017;; 108 (1): 238–247. doi: https://doi.org/10.1785/0120170115 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract The tS–tP earthquake early warning algorithm measures the energy of the P‐wave coda on the vertical component in the tS–tP period to make a magnitude threshold estimation. The algorithm is based on two parameters: the logarithm of the peak ground acceleration, max(a(tS–tP)) and the logarithmic cumulative acceleration SA(tS–tP)⁠. The model is built using a learning algorithm that iteratively parameterizes the linear fit of max(a(tS–tP)) and SA(tS–tP) to Mw in segments. Training datasets were based on 324 accelerograms from 101 earthquakes (⁠4.8≤Mw≤8.1⁠) in the Mexican subduction zone from 1985 to 2013. The algorithm is supervised to avoid outliers in the data. The process results in a family of linear equations parameterizing the observations to magnitude m(tS–tP) calibrated to the observed Mw⁠. The algorithm was successfully tested using a dataset of 28 earthquakes in the Mexican subduction zone, from 2014 to 2017. The performance of tS–tP algorithm was tested as a warning tool using 89 earthquakes in the Mexican subduction zone from 1985 to 2017, that met the criterion of having at least two stations within 70 km from the epicenter. The results show that 79 were correctly screened. The magnitude of six events was overestimated and four were underestimated. These earthquakes had an unfavorable station distribution. The Mw 6 South Napa, California, earthquake of 24 August 2014 was used also as a test case. The two closest stations identified it as Mw≥5.8 within 2 s after the arrival of the P phase. This resulted in a lead time of 10 s in Berkeley and 12 s in San Francisco, prior to the arrival of the S waves. Thus, the tS–tP algorithm proves to be a reliable tool for seismic early warning where hypocenters are close to the target cities. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.