Seismic rupture and tsunami hazard of the Java margin in relation to plate interface geometry
Heidrun KoppY. DjajadihardjaErnst R. FluehDirk KlaeschenCharles S. MuellerLars PlanertJava C. ReichertAlexey ShulginAndreas Wittwer
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Margin (machine learning)
Earthquake rupture
Interface (matter)
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Earthquakes and their corresponding tsunamis pose significant hazard to popu- lated regions around the world. Therefore, it is critically important that we seek to more fully understand the physics of the combined earthquake-tsunami system. One way to address this goal is through numerical modeling. The work discussed herein focuses on combining dynamic earthquake and tsunami models through the use of the Finite Element Method (FEM) and the Finite Difference Method (FDM). Dynamic earthquake models ac- count for the force that the entire fault system exerts on each individual element of the model for each time step, so that earthquake rupture takes a path based on the physics of the model; dynamic tsunami models can incorporate water height variations to produce water wave formation, propagation, and inundation. Chapter 1 provides an introduction to some important concepts and equations of elastodynamics and fluid dynamics as well as a brief example of the FEM. In Chapter 2, we investigate the 3-D effects of realistic fault dynamics on slip, free surface deformation, and resulting tsunami formation from an Mw 9 megathrust earthquake offshore Southern Alaska. Corresponding tsunami models, which use a FDM to solve linear long-wave equations, match sea floor deformation, in time, to the free surface deformation from the rupture simulations. Tsunamis generated in this region could have large adverse effects on Pacific coasts. In Chapter 3, we construct a 3-D dynamic rupture model of an earthquake on a reverse fault structure offshore Southern California to model the resulting tsunami, with a goal of elucidating the seismic and tsunami hazard in this area. The corresponding tsunami model uses final seafloor displacements from the rupture model as initial conditions to compute local propagation and inundation, resulting in large peak tsunami amplitudes northward and eastward due to site and path effects. In Chapter 4, we begin to evaluate 2-D earthquake source parameters from characteristics of the Rayleigh-wave field by running a suite of 2-D dynamic rupture models on thrust/reverse faults that vary in dip angle and fault curvature, and with equivalent prestress conditions such as constant traction across the fault or variable prestress distributions. We compare traveling Rayleigh-wave breakout amplitudes with fault slip distribution. Such Rayleigh- wave analysis has implications for early estimation of far-field tsunami amplitude, since source parameters are directly related to tsunami generation and propagation.
Earthquake rupture
Tsunami earthquake
Earthquake simulation
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Abstract The SW Iberian margin is one of the most seismogenic and tsunamigenic areas in W‐Europe, where large historical and instrumental destructive events occurred. To evaluate the sensitivity of the tsunami impact on the coast of SW Iberia and NW Morocco to the fault geometry and slip distribution for local earthquakes, we carried out a set of tsunami simulations considering some of the main known active crustal faults in the region: the Gorringe Bank (GBF), Marquês de Pombal (MPF), Horseshoe (HF), North Coral Patch (NCPF) and South Coral Patch (SCPF) thrust faults, and the Lineament South strike‐slip fault. We started by considering for all of them relatively simple planar faults featuring with uniform slip distribution; we then used a more complex 3D fault geometry for the faults constrained with a large 2D multichannel seismic dataset (MPF, HF, NCPF, and SCPF); and finally, we used various heterogeneous slip distributions for the HF. Our results show that using more complex 3D fault geometries and slip distributions, the peak wave height at the coastline can double compared to simpler tsunami source scenarios from planar fault geometries. Existing tsunami hazard models in the region use homogeneous slip distributions on planar faults as initial conditions for tsunami simulations and therefore underestimate tsunami hazard. Complex 3D fault geometries and non‐uniform slip distribution should be considered in future tsunami hazard updates. The tsunami simulations also support the finding that submarine canyons attenuate the wave height reaching the coastline, while submarine ridges and shallow shelves have the opposite effect.
Thrust fault
Transform fault
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Seismic energy
Tsunami earthquake
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In this study, we develop stochastic random-field slip models for the 2011 Tohoku earthquake and conduct a rigorous sensitivity analysis of tsunami hazards with respect to the uncertainty of earthquake slip and fault geometry. Synthetic earthquake slip distributions generated from the modified Mai-Beroza method captured key features of inversion-based source representations of the mega-thrust event, which were calibrated against rich geophysical observations of this event. Using original and synthesised earthquake source models (varied for strike, dip, and slip distributions), tsunami simulations were carried out and the resulting variability in tsunami hazard estimates was investigated. The results highlight significant sensitivity of the tsunami wave profiles and inundation heights to the coastal location and the slip characteristics, and indicate that earthquake slip characteristics are a major source of uncertainty in predicting tsunami risks due to future mega-thrust events.
Tsunami earthquake
Earthquake simulation
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Tsunami wave
Tsunami earthquake
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Earthquake rupture
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Numerical simulation of tsunami is currently utilized to estimate the arrival time,amplitude and wave length information of the tsunami;it can also provide abundant constraints to investigate the inversion results of the earthquake rapture processes.Our tsunami models based on two-dimension shallow water equations are proposed to study the tsunami propagation characteristics of the March 11,2011Tohoku earthquake,Japan.The overall distribution of tsunami along the coast line,average wave height,and the maximum tsunami and location are obtained from our numerical calculations and are compared with the observation data available.It is found that among the different rupture models from several seismological agencies,most of them could approximately match the features of the tsunami distribution.One of our interesting discoveries is that the simple average dislocation model can produce a closer average value of wave height with the observed results.
Tsunami earthquake
Tsunami wave
Arrival time
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