Tremor-like Signals Along the San Jacinto Fault: Observations From a Long-term Dense Seismic Array (Faultscan)
Description:
Since their identification in the early 21st century, tectonic tremors have attracted considerable interest as they provide a unique window into the mechanisms and activity of fault systems. However, their emergent character and lack of clear phase onsets make them difficult to detect and to distinguish from anthropogenic noise. In the San Jacinto Fault region, recent observations of tremor-like signals have fueled debate within the seismological community as to whether these signals originate from deep tectonic processes or from human activity.
In this study, we investigate the presence and characteristics of tremor-like signals along the San Jacinto Fault in Southern California. Our approach relies on slant-stacking applied to data from the long-term FaultScan dense nodal array, composed of 300 stations deployed at the Piñon Flat Observatory between mid-April 2022 and mid-October 2024. We perform beamforming at crustal P- and S-wave velocities, typically associated with tremor propagation, and develop a detection proxy based on slant-stacked waveform envelopes. To minimize contamination from anthropogenic sources (e.g., train-induced signals from the Coachella Valley) and wind-generated noise, we focus on coherent body-wave energy and azimuths oriented toward the fault zone.
Our search for tectonic tremors along the San Jacinto Fault turns up empty. Instead, we observe a variety of tremor-like signals, dominated by acoustic T-phases from large offshore earthquakes in the Tonga subduction zone, as well as well-resolved earthquake sequences and spectral-line signals. We also identify one intriguing T-phase–like sequence associated with the October 2023 offshore Japan volcanic crisis.
Session: New Frontiers in Seismic Observations and Modeling with Innovative Methods and Emerging Data on Earth and Other Planets - I
Type: Oral
Date: 4/17/2026
Presentation Time: 11:15 AM (local time)
Presenting Author: Quentin Higueret
Student Presenter: No
Invited Presentation:
Poster Number:
Authors
Quentin Higueret Presenting Author Corresponding Author qhigueret@gmail.com University Grenoble Alpes |
Margot Vignon-Livache margot.vignon--livache@univ-grenoble-alpes.fr University Grenoble Alpes |
Florent Brenguier florent.brenguier@univ-grenoble-alpes.fr University Grenoble Alpes |
Aurelien Mordret aurmo@geus.dk Geological Survey of Denmark and Greenland |
Yixiao Sheng yxsheng@ustc.edu.cn University of Science and Technology of China |
Francois Lavoue francois.lavoue@univ-grenoble-alpes.fr University Grenoble Alpes |
Frank Vernon flvernon@ucsd.edu University of California, San Diego |
Daniel Hollis ddhollis@ucsd.edu University of California, San Diego |
Coralie Aubert coralie.aubert@univ-grenoble-alpes.fr University Grenoble Alpes |
Yehuda Ben-Zion benzion@usc.edu University of California, Los Angeles, Los Angeles, California, United States |
Tremor-like Signals Along the San Jacinto Fault: Observations From a Long-term Dense Seismic Array (Faultscan)
Category
New Frontiers in Seismic Observations and Modeling with Innovative Methods and Emerging Data on Earth and Other Planets