Earthquake Rupture on Multiple Splay Faults and Its Effect on Tsunamis
| Autor: | van Zelst, I., Rannabauer, L., Gabriel, A.‐A., van Dinther, Y., 4 Department of Informatics Technical University of Munich Munich Germany, 5 Geophysics Department of Earth and Environmental Sciences LMU Munich Munich Germany, 1 Seismology and Wave Physics Institute of Geophysics, Department of Earth Sciences ETH Zürich Zürich Switzerland |
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| Přispěvatelé: | Tectonics |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
ddc:551
subduction zone numerical modelling results Seismic cycle related deformations GLOBAL CHANGE Abrupt/rapid climate change Climate variability Earth system modeling Impacts of global change Land/atmosphere interactions Oceans Regional climate change Sea level change Solid Earth Water cycles HYDROLOGY Climate impacts Estimation and forecasting Hydrological cycles and budgets INFORMATICS Forecasting IONOSPHERE MAGNETOSPHERIC PHYSICS MARINE GEOLOGY AND GEOPHYSICS Gravity and isostasy MATHEMATICAL GEOPHYSICS Prediction Probabilistic forecasting ATMOSPHERIC PROCESSES Climate change and variability Climatology General circulation Ocean/atmosphere interactions Regional modeling Theoretical modeling OCEANOGRAPHY: GENERAL Climate and interannual variability Numerical modeling Ocean predictability and prediction NATURAL HAZARDS Atmospheric Geological Oceanic Monitoring forecasting prediction Physical modeling Climate impact Risk Disaster risk analysis and assessment OCEANOGRAPHY: PHYSICAL Tsunamis and storm surges Air/sea interactions Decadal ocean variability Ocean influence of Earth rotation Sea level: variations and mean Surface waves and tides PALEOCEANOGRAPHY POLICY SCIENCES Benefit-cost analysis RADIO SCIENCE Interferometry Ionospheric physics Radio oceanography SEISMOLOGY Earthquake dynamics Seismicity and tectonics Subduction zones Continental crust Earthquake ground motions and engineering seismology Earthquake source observations Earthquake interaction forecasting and prediction Volcano seismology SPACE WEATHER Policy TECTONOPHYSICS Dynamics: seismotectonics VOLCANOLOGY Volcano/climate interactions Atmospheric effects Volcano monitoring Effusive volcanism Mud volcanism Explosive volcanism Volcanic hazards and risks Research Article earthquake tsunami dynamic rupture splay fault numerical modeling [Seismology ATMOSPHERIC COMPOSITION AND STRUCTURE Air/sea constituent fluxes Volcanic effects BIOGEOSCIENCES Climate dynamics Modeling COMPUTATIONAL GEOPHYSICS Numerical solutions CRYOSPHERE Avalanches Mass balance EXPLORATION GEOPHYSICS Gravity methods GEODESY AND GRAVITY Transient deformation Tectonic deformation Time variable gravity Gravity anomalies and Earth structure Ocean monitoring with geodetic techniques Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions Global change from geodesy Satellite geodesy] ddc numerical modeling Geophysics Geochemistry and Petrology Space and Planetary Science Earth and Planetary Sciences (miscellaneous) |
| Zdroj: | Journal of Geophysical Research: Solid Earth, 127(8), 1 Journal of Geophysical Research: Solid Earth, 127 (8) J. Geophys. Res. |
| ISSN: | 2169-9313 |
| Popis: | Detailed imaging of accretionary wedges reveals splay fault networks that could pose a significant tsunami hazard. However, the dynamics of multiple splay fault activation during megathrust earthquakes and the consequent effects on tsunami generation are not well understood. We use a 2‐D dynamic rupture model with complex topo‐bathymetry and six curved splay fault geometries constrained from realistic tectonic loading modeled by a geodynamic seismic cycle model with consistent initial stress and strength conditions. We find that all splay faults rupture coseismically. While the largest splay fault slips due to a complex rupture branching process from the megathrust, all other splay faults are activated either top down or bottom up by dynamic stress transfer induced by trapped seismic waves. We ascribe these differences to local non‐optimal fault orientations and variable along‐dip strength excess. Generally, rupture on splay faults is facilitated by their favorable stress orientations and low strength excess as a result of high pore‐fluid pressures. The ensuing tsunami modeled with non‐linear 1‐D shallow water equations consists of one high‐amplitude crest related to rupture on the longest splay fault and a second broader wave packet resulting from slip on the other faults. This results in two episodes of flooding and a larger run‐up distance than the single long‐wavelength (300 km) tsunami sourced by the megathrust‐only rupture. Since splay fault activation is determined by both variable stress and strength conditions and dynamic activation, considering both tectonic and earthquake processes is relevant for understanding tsunamigenesis. Plain Language Summary: In subduction zones, where one tectonic plate moves beneath another, earthquakes can occur on many different faults. Splay faults are relatively steep faults that branch off the largest fault (the megathrust) in a subduction zone. As they are steeper than the megathrust, the same amount of movement on them could result in more vertical displacement of the seafloor. Therefore, splay faults are thought to play an important role in the generation of tsunamis. Here, we use computer simulations to study if an earthquake can break multiple splay faults at once and how this affects the resulting tsunami. We find that multiple splay faults can indeed fail during a single earthquake due to the stress changes from trapped seismic waves, which promote rupture on splay faults. Rupture on splay faults results in larger seafloor displacements with smaller wavelengths, so the ensuing tsunami is bigger and results in two main flooding episodes at the coast. Our results show that it is important to consider rupture on splay faults when assessing tsunami hazard. Key Points: Multiple splay faults can be activated during a single earthquake by megathrust slip and dynamic stress transfer due to trapped waves. Splay fault activation is facilitated by their favorable orientation with respect to the local stress field and their closeness to failure. Long‐term geodynamic stresses and fault geometries affect dynamic splay fault rupture and the subsequent tsunami. Volkswagen Foundation (VolkswagenStiftung) http://dx.doi.org/10.13039/501100001663 Royal Society (The Royal Society) http://dx.doi.org/10.13039/501100000288 EC | H2020 | H2020 Priority Excellent Science | H2020 European Research Council (ERC) http://dx.doi.org/10.13039/100010663 Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659 National Science Foundation (NSF) http://dx.doi.org/10.13039/100000001 https://github.com/TUM-I5/SWE https://doi.org/10.5281/zenodo.6969455 |
| Databáze: | OpenAIRE |
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