Friday, December 1, 2023


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Earthquakes have a preparatory stage that occurs years before the actual rupture.

Map and 2 graphs form the paper

The Editors’ Highlights provide brief overviews of recent papers selected by AGU’s journal editors.

The source is Geophysical Research Letters.

Due to the significant destruction caused by major earthquakes, humans have devoted considerable resources to identify potential warning signs in the months leading up to their occurrence. Identifying such indicators would not only aid in better preparation for earthquakes, but also contribute to a deeper understanding of their underlying mechanisms. However, there is limited concrete evidence of precursory behavior, with most findings based on speculation or lacking proper documentation.

In 2010, Tanaka published a thought-provoking paper that presented compelling proof indicating that the 2004 M9.0 Sumatra-Andaman earthquake, one of the biggest earthquakes of the century, experienced a statistically significant alteration in its tidal triggering of minor earthquakes in the ten years leading up to the event.

In 2023, Beaucé and colleagues conducted a study to investigate the possibility that the well-documented 2019 M7.1 Ridgecrest earthquake had increased sensitivity to tides in the years leading up to the mainshock. They utilized a new earthquake catalog containing more than 150,000 events and discovered a significant change in nearby tidal triggering prior to the Ridgecrest earthquake. This finding supports Tanaka’s hypothesis and implies that all extensively studied earthquakes may exhibit early warning signs that could aid in earthquake prediction.

Reference: Beaucé, E., Poli, P., Waldhauser, F., Holtzman, B., & Scholz, C. (2023). Increased seismic activity leading up to the 2019 Ridgecrest earthquake in California. Geophysical Research Letters, 50, e2023GL104375.

—Victor Tsai, Associate Editor, Geophysical Research Letters

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