What controls the remobilization and deformation of surficial sediment by seismic shaking? Linking lacustrine slope stratigraphy to great earthquakes in South–Central Chile
| العنوان: | What controls the remobilization and deformation of surficial sediment by seismic shaking? Linking lacustrine slope stratigraphy to great earthquakes in South–Central Chile |
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| المؤلفون: | Mario Pino, Gerald Degenhart, Jasper Moernaut, Maarten Van Daele, Ariana Molenaar, Roberto Urrutia, Thomas Vandorpe, Michael Strasser, Marc De Batist |
| المصدر: | Sedimentology SEDIMENTOLOGY |
| بيانات النشر: | John Wiley and Sons Inc., 2021. |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | 010506 paleontology, Peak ground acceleration, Stratigraphy, SUBDUCTION ZONE, MAGNITUDES, Fault (geology), Deformation (meteorology), 010502 geochemistry & geophysics, 01 natural sciences, Soft-sediment deformation structures, TSUNAMI, Sedimentary depositional environment, TOHOKU-OKI EARTHQUAKE, RECURRENCE, Geomorphology, Chilean subduction zone, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, LIQUEFACTION, Sediment, Geology, RECORD, Original Articles, 15. Life on land, Turbidite, turbidite, surficial remobilization, soft sediment deformation, Earth and Environmental Sciences, LAKE-SEDIMENTS, Sedimentary rock, Original Article, palaeoseismology, MOBILIZATION, FAULT |
| الوصف: | Remobilization and deformation of surficial subaqueous slope sediments create turbidites and soft sediment deformation structures, which are common features in many depositional records. Palaeoseismic studies have used seismically‐induced turbidites and soft sediment deformation structures preserved in sedimentary sequences to reconstruct recurrence patterns and – in some cases – allow quantifying rupture location and magnitude of past earthquakes. However, current understanding of earthquake‐triggered remobilization and deformation lacks studies targeting where these processes take place, the subaqueous slope and involving direct comparison of sedimentary fingerprint with well‐documented historical earthquakes. This study investigates the sedimentary imprint of six megathrust earthquakes with varying rupture characteristics in 17 slope sediment cores from two Chilean lakes, Riñihue and Calafquén, and evaluates how it links to seismic intensity, peak ground acceleration, bracketed duration and slope angle. Centimetre‐scale stratigraphic gaps ranging from ca 1 to 20 cm – caused by remobilization of surficial slope sediment – were identified using high‐resolution multi‐proxy core correlation of slope to basin cores, and six types of soft sediment deformation structures ranging from ca 1 to 25 cm thickness using high‐resolution three‐dimensional X‐ray computed tomography data. Stratigraphic gaps occur on slope angles of ≥2.3°, whereas deformation already occurs from slope angle 0.2°. The thickness of both stratigraphic gaps and soft sediment deformation structures increases with slope angle, suggesting that increased gravitational shear stress promotes both surficial remobilization and deformation. Seismic shaking is the dominant trigger for surficial remobilization and deformation at the studied lakes. Total remobilization depth correlates best with bracketed duration and is highest in both lakes for the strongest earthquakes (M w ca 9.5). In lake Riñihue, soft sediment deformation structure thickness and type correlate best with peak ground acceleration providing the first field‐based evidence of progressive soft sediment deformation structure development with increasing peak ground acceleration for soft sediment deformation structures caused by Kelvin‐Helmholtz instability. The authors propose that long duration and low frequency content of seismic shaking favours surficial remobilization, whereas ground motion amplitude controls Kelvin‐Helmholtz instability‐related soft sediment deformation structure development. |
| وصف الملف: | application/pdf |
| اللغة: | English |
| تدمد: | 1365-3091 0037-0746 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6708ea0c35071d9c429ed0b08da25ec3Test http://europepmc.org/articles/PMC8518804Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....6708ea0c35071d9c429ed0b08da25ec3 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 13653091 00370746 |
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