The cryptic seismic potential of the Pichilemu blind fault in Chile revealed by off-fault geomorphology
- The first step towards assessing hazards in seismically active regions involves mapping capable faults and estimating their recurrence times. While the mapping of active faults is commonly based on distinct geologic and geomorphic features evident at the surface, mapping blind seismogenic faults is complicated by the absence of on-fault diagnostic features. Here we investigated the Pichilemu Fault in coastal Chile, unknown until it generated a Mw 7.0 earthquake in 2010. The lack of evident surface faulting suggests activity along a partly-hidden blind fault. We used off-fault deformed marine terraces to estimate a fault-slip rate of 0.52 +/- 0.04 m/ka, which, when integrated with satellite geodesy suggests a 2.12 +/- 0.2 ka recurrence time for Mw similar to 7.0 normal-faulting earthquakes. We propose that extension in the Pichilemu region is associated with stress changes during megathrust earthquakes and accommodated by sporadic slip during upper-plate earthquakes, which has implications for assessing the seismic potential of crypticThe first step towards assessing hazards in seismically active regions involves mapping capable faults and estimating their recurrence times. While the mapping of active faults is commonly based on distinct geologic and geomorphic features evident at the surface, mapping blind seismogenic faults is complicated by the absence of on-fault diagnostic features. Here we investigated the Pichilemu Fault in coastal Chile, unknown until it generated a Mw 7.0 earthquake in 2010. The lack of evident surface faulting suggests activity along a partly-hidden blind fault. We used off-fault deformed marine terraces to estimate a fault-slip rate of 0.52 +/- 0.04 m/ka, which, when integrated with satellite geodesy suggests a 2.12 +/- 0.2 ka recurrence time for Mw similar to 7.0 normal-faulting earthquakes. We propose that extension in the Pichilemu region is associated with stress changes during megathrust earthquakes and accommodated by sporadic slip during upper-plate earthquakes, which has implications for assessing the seismic potential of cryptic faults along convergent margins and elsewhere.…
Author details: | Julius Jara-MuñozORCiDGND, Daniel MelnickORCiD, Shaoyang Li, Anne SocquetORCiD, Joaquín Cortés-Aranda, Dominik Brill, Manfred R. StreckerORCiDGND |
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DOI: | https://doi.org/10.1038/s41467-022-30754-1 |
ISSN: | 2041-1723 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/35690605 |
Title of parent work (English): | Nature communications |
Publisher: | Nature Research |
Place of publishing: | Berlin |
Publication type: | Article |
Language: | English |
Date of first publication: | 2022/06/11 |
Publication year: | 2022 |
Release date: | 2024/07/01 |
Volume: | 13 |
Issue: | 1 |
Article number: | 3371 |
Number of pages: | 13 |
Funding institution: | Millennium Scientific Initiative (ICM) of the Chilean government; [C160025]; Chilean National Fund for Development of Science and; Technology (FONDECYT) [1181479, 11180509, 1190258]; ANID PIA Anillo; [ACT192169]; MARISCOS (MAule eaRthquake: Integration of Seismic Cycle; Observations and Structural investigations) project - German Science; Foundation (DFG) [STR373/30-1]; DFG "LIFE" project [JA2860/1]; DFG; "ARTE" project [STR373/41-1] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Geowissenschaften |
Peer review: | Referiert |
Publishing method: | Open Access / Gold Open-Access |
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License (German): | ![]() |