Roughness Characteristics of Oceanic Seafloor Prior to Subduction in Relation to the Seismogenic Potential of Subduction Zones
| Autor: | Serge Lallemand, Arnauld Heuret, Michel Peyret, Diane Arcay, Elenora van Rijsingen |
|---|---|
| Přispěvatelé: | Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Roma Tre University |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
010504 meteorology & atmospheric sciences
Seamount proxy Surface finish 010502 geochemistry & geophysics Spatial distribution rupture dynamics 01 natural sciences wavelength Geochemistry and Petrology Bathymetry 0105 earth and related environmental sciences [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics geography geography.geographical_feature_category Subduction subduction earthquake Seafloor spreading Wavelength Geophysics Amplitude 13. Climate action subduction interface seafloor roughness Geology Seismology |
| Zdroj: | Geochemistry, Geophysics, Geosystems Geochemistry, Geophysics, Geosystems, AGU and the Geochemical Society, 2018, 19 (7), pp.2121-2146. ⟨10.1029/2018GC007434⟩ |
| ISSN: | 1525-2027 |
| Popis: | International audience; We have developed a new approach to characterize the seafloor roughness seaward of the trenches, as a proxy for estimating the roughness of the subduction interface. We consider that abrupt elevation changes over given wavelengths play a larger role in the seismogenic behavior of the subduction interface than the amplitude of bathymetric variations alone. The new database, SubRough, provides roughness parameters at selected spatial wavelengths. Here we mainly discuss the spatial distribution of short‐ (12–20 km) and long‐wavelength (80–100 km) roughness, RSW and RLW, respectively, along 250‐km‐wide strips of seafloor seaward of the trenches. Compared with global trend, seamounts show distinct roughness signature of much larger amplitudes at both wavelengths, whereas aseismic ridges only differ from the global trend at long wavelengths. Fracture zones cannot be distinguished from the global trend, which suggests that their potential effect on rupture dynamics is not the consequence of their roughness, at least not at these wavelengths. Based on RLW amplitude, segments along subduction zones can be defined from rough to smooth. Subduction zones like the Solomons or the Ryukyus appear dominantly rough, whereas others like the Andes or Cascadia are dominantly smooth. The relative contribution of smooth versus rough areas in terms of respective lateral extents probably plays a role in multipatch rupture and thus in the final earthquake magnitude. We observe a clear correlation between high seismic coupling and relatively low roughness and conversely between low seismic coupling and relatively high seafloor roughness. |
| Databáze: | OpenAIRE |
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