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Published March 2018 | Published + Supplemental Material
Journal Article Open

The limits of earthquake early warning: Timeliness of ground motion estimates

Abstract

The basic physics of earthquakes is such that strong ground motion cannot be expected from an earthquake unless the earthquake itself is very close or has grown to be very large. We use simple seismological relationships to calculate the minimum time that must elapse before such ground motion can be expected at a distance from the earthquake, assuming that the earthquake magnitude is not predictable. Earthquake early warning (EEW) systems are in operation or development for many regions around the world, with the goal of providing enough warning of incoming ground shaking to allow people and automated systems to take protective actions to mitigate losses. However, the question of how much warning time is physically possible for specified levels of ground motion has not been addressed. We consider a zero-latency EEW system to determine possible warning times a user could receive in an ideal case. In this case, the only limitation on warning time is the time required for the earthquake to evolve and the time for strong ground motion to arrive at a user's location. We find that users who wish to be alerted at lower ground motion thresholds will receive more robust warnings with longer average warning times than users who receive warnings for higher ground motion thresholds. EEW systems have the greatest potential benefit for users willing to take action at relatively low ground motion thresholds, whereas users who set relatively high thresholds for taking action are less likely to receive timely and actionable information.

Additional Information

© 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). Received for publication September 26, 2017. Accepted for publication February 8, 2018. We thank N. Beeler, B. Brooks, M. Hoshiba, A. Thomas, and an anonymous reviewer for reviewing our initial manuscript and the ShakeAlert project group for discussions. Funding: M.-A.M. was funded by the Swiss National Science Foundation and the Gordon and Betty Moore Foundation. Author contributions: S.E.M. ran analysis. M.-A.M. contributed data. A.S.B. and T.C.H. provided GMPE analysis inputs. E.S.C. provided EEW expertise. The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials, or are available from public sources specified therein. Additional data related to this paper may be requested from the authors.

Attached Files

Published - eaaq0504.full.pdf

Supplemental Material - aaq0504_DatafileS1.xlsx

Supplemental Material - aaq0504_MovieS1.mp4

Supplemental Material - aaq0504_SM.pdf

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Additional details

Created:
August 19, 2023
Modified:
October 18, 2023