Tracking the Spatio‐Temporal Evolution of Foreshocks Preceding the Mw 6.1 2009 L’Aquila Earthquake
Name
JGR Solid Earth - 2022 - Cabrera - Tracking the Spatio‐Temporal Evolution of Foreshocks Preceding the Mw 6 1 2009 L Aquila.pdf
Description
Published version
Size
9.24 MB
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Adobe PDF
Checksum (MD5)
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Author(s)
Cabrera, Leoncio
Poli, Piero
Frank, William B
Date Issued
March 7, 2022
Journal
Journal of Geophysical Research: Solid Earth
Publisher
American Geophysical Union
Citation
Cabrera, L., Poli, P., & Frank, W. B. (2022). Tracking the spatio-temporal evolution of foreshocks preceding the Mw 6.1 2009 L’Aquila earthquake. Journal of Geophysical Research: Solid Earth, 127, e2021JB023888.
Version
Final published version
Abstract
How faulting processes lead to a large earthquake is a fundamental question in seismology. To better constrain this pre‐seismic stage, we create a dense seismic catalog via template matching to analyze the precursory phase of the Mw 6.1 L’Aquila earthquake that occurred in central Italy in 2009. We estimate several physical parameters in time, such as the coefficient of variation, the seismic moment release, the effective stress drop, and analyze spatio‐temporal patterns to study the evolution of the sequence and the earthquake interactions. We observe that the precursory phase experiences multiple accelerations of the seismicity rate that we divide into two main sequences with different signatures and features: the first part exhibits weak earthquake interactions, quasi‐continuous moment release, slow spatial migration patterns, and a lower effective stress drop, pointing to aseismic processes. The second sequence exhibits strong temporal clustering, fast seismicity expansion, and a larger effective stress drop typical of a stress transfer process. We interpret the differences in seismicity behaviors between the two sequences as distinct physical mechanisms that are controlled by different physical properties of the fault system. We conclude that the L’Aquila earthquake is preceded by a complex preparation, made up of different physical processes over different time scales on faults with different physical properties.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
10.1029/2021jb023888
