Rapid earthquake magnitude classification via P-wave strains from borehole strainmeters and Distributed Acoustic Sensing

Nature Communications
By: , and 

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Abstract

Distributed Acoustic Sensing (DAS) offers a promising approach for earthquake early warning (EEW) in settings where seismic networks are costly to maintain. By repurposing fiber-optic cables as dense strainmeter arrays, DAS enables real-time earthquake detection wherever those fibers are accessible. However, poor azimuthal coverage and challenges in estimating magnitude from strain measurements remain key hurdles in applying for earthquake monitoring. Here, we develop a machine learning method to distinguish large (M≥5.4) earthquakes from smaller ones within the first 4 seconds of a strain waveform after a P-wave arrival without determining location. Using ensemble decision tree models trained on borehole strainmeter data (3.5≤M≤7.1) and tested on onshore DAS waveforms (including the 2024 M7 Offshore Cape Mendocino earthquake), we find that low-frequency (0.2–0.5 Hz) continuous wavelet transform coefficients are the strongest predictors of magnitude, in addition to strain amplitude. Both DAS and borehole strainmeters effectively capture long-period strain signals, making these findings valuable for EEW systems. Our method shows high precision compared to the real-time EEW system, ShakeAlert®, supporting the position that DAS is a viable technology for earthquake monitoring and magnitude classification.

Suggested Citation

Sawi, T., McGuire, J.J., Barbour, A.J., Yoon, C., Karrenbach, M., and Stewart, C., 2026, Rapid earthquake magnitude classification via P-wave strains from borehole strainmeters and Distributed Acoustic Sensing: Nature Communications, v. 17, 4776, 14 p., https://doi.org/10.1038/s41467-026-72223-z.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Rapid earthquake magnitude classification via P-wave strains from borehole strainmeters and Distributed Acoustic Sensing
Series title Nature Communications
DOI 10.1038/s41467-026-72223-z
Volume 17
Publication Date June 03, 2026
Year Published 2026
Language English
Publisher Nature
Contributing office(s) Earthquake Science Center
Description 4776, 14 p.
Country United States
State California
Additional publication details