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Real-Time Earthquake Detection and Alerting Behavior of PLUM Ground-Motion-Based Early Warning in the United States

Saunders, Jessie K. and Minson, Sarah E. and Baltay, Annemarie S. and Bunn, Julian J. and Cochran, Elizabeth S. and Kilb, Deborah L. and O'Rourke, Colin T. and Hoshiba, Mitsuyuki and Kodera, Yuki (2022) Real-Time Earthquake Detection and Alerting Behavior of PLUM Ground-Motion-Based Early Warning in the United States. Bulletin of the Seismological Society of America, 112 (5). pp. 2668-2688. ISSN 0037-1106. doi:10.1785/0120220022.

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We examine the real-time earthquake detection and alerting behavior of the Propagation of Local Undamped Motion (PLUM) earthquake early warning (EEW) algorithm and compare PLUM’s performance with the real-time performance of the current source-characterization-based ShakeAlert System. In the United States (U.S.), PLUM uses a two-station approach to detect earthquakes. Once a detection is confirmed, observed modified Mercalli intensity (MMI) distributions are forecast onto a regular grid, in which the preferred alert regions are grid cells with MMI 4.0+ forecasts. Although locations of dense station coverage allow PLUM to detect small (M < 4.5) earthquakes typically not considered for EEW in the U.S., a PLUM detection on a small earthquake does not always generate an alert. This is because PLUM alerts are determined by current shaking distributions. If the MMI 4.0+ shaking subsides prior to detection confirmation by shaking at a second neighboring station, the prior MMI 4.0+ information will not be in the alert forecasts. Of the 432 M 3.0+ U.S. West Coast earthquakes in 2021, 33 produced ground motions large enough to be detected by PLUM. Twenty-four generated MMI 4.0+ PLUM alerts, whereas ShakeAlert issued public EEW alerts for 13 of these earthquakes. We compare PLUM and ShakeAlert alert regions with ShakeMap and “Did You Feel It?” intensity distributions. Because PLUM alert regions surround stations observed to have strong ground motions (regardless of earthquake magnitude), PLUM alerts reliably include locations that experience significant shaking. This is not necessarily the case for ShakeAlert alert regions when there are large errors in magnitude or epicenter estimates. For two of the largest earthquakes in our real-time dataset, the M 6.0 Antelope Valley and M 5.1 Petrolia earthquakes, the inclusion of PLUM would have improved real-time ShakeAlert performance. Our results indicate that incorporation of PLUM into ShakeAlert will improve the robustness of the EEW system.

Item Type:Article
Related URLs:
URLURL TypeDescription
Saunders, Jessie K.0000-0001-5340-6715
Minson, Sarah E.0000-0001-5869-3477
Baltay, Annemarie S.0000-0002-6514-852X
Bunn, Julian J.0000-0002-3798-298X
Cochran, Elizabeth S.0000-0003-2485-4484
Kilb, Deborah L.0000-0002-7252-4167
O'Rourke, Colin T.0000-0001-5403-4685
Hoshiba, Mitsuyuki0000-0001-9701-5986
Kodera, Yuki0000-0002-8071-2360
Additional Information:The authors thank Associate Editor Adrien Oth, Dara Goldberg, Jamie Steidl, and two anonymous reviewers for helpful comments that improved this article. Discussions with ShakeAlert project team members also improved this work. The authors thank the members of the Social Writing While Social Distancing group for their encouragement. This work was funded by the U.S. Geological Survey (USGS) Earthquake Hazards Program and was conducted when J. K. Saunders was at the USGS Earthquake Science Center (now at California Institute of Technology). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Group:Seismological Laboratory
Funding AgencyGrant Number
Issue or Number:5
Record Number:CaltechAUTHORS:20221101-827781300.5
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117684
Deposited By: Research Services Depository
Deposited On:11 Nov 2022 15:53
Last Modified:11 Nov 2022 15:53

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