The role of topography and lateral velocity heterogeneities on near-source scattering and ground-motion variability

Imperatori, Walter; Martin, P.

doi:10.1093/gji/ggv281

Cited by 59 publications

(27 citation statements)

References 86 publications

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“…We think that for the frequency range considered here, scattering due to topography and a rather smooth 3D Earth model is generally insufficient to generate realistically scattered waves [Imperatori and Mai , 2015], thereby affecting the waveform misfit. Note, however, that the farthest recording (at SAL) demonstrates a very consistent overall waveform character, including the coda waves, as regional wavepropagation effects dominate (e.g.…”

Section: Waveformsmentioning

confidence: 98%

Landers 1992 "reloaded": Integrative dynamic earthquake rupture modeling

Gabriel

Wollherr

Schliwa

et al. 2018

Preprint

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Key Points:• A new integrative physics-based simulation of the 1992 Landers earthquake reproduces a broad range of independent observation • Sustained dynamic rupture interconnecting the complex fault segments constraints pre-stress and fault strength • We discuss the interplay of rupture transfers, geometric fault complexity, initial stress, viscoelastic attenuation, and off-fault plasticity AbstractThe 1992 M w 7.3 Landers earthquake is perhaps one of the best studied seismic events. However, many aspects of the dynamics of the rupture process are still puzzling, e.g. how did rupture transfer between fault segments? We present 3D spontaneous dynamic rupture simulations of a new degree of realism, incorporating the interplay of fault geometry, topography, 3D rheology, off-fault plasticity and viscoelastic attenuation. The surprisingly unique scenario reproduces a broad range of observations, including final slip distribution, seismic moment-rate function, seismic waveform characteristics and peak ground velocities, as well as shallow slip deficits and mapped off-fault deformation patterns. Sustained dynamic rupture of all fault segments in general, and rupture transfers in particular, put strong constraints on amplitude and orientation of initial fault stresses and friction. Source dynamics include dynamic triggering over large distances and direct branching; rupture terminates spontaneously on most of the principal fault segments. We achieve good agreement between synthetic and observed waveform characteristics and associated peak ground velocities. Despite very complex rupture evolution, ground motion variability is close to what is commonly assumed in Ground Motion Prediction Equations. We examine the effects of variations in modeling parameterization, e.g. purely elastic setups or models neglecting viscoelastic attenuation, in comparison to our preferred model. Our integrative dynamic modeling approach demonstrates the potential of consistent in-scale earthquake rupture simulations for augmenting earthquake source observations and improving the understanding of earthquake source physics of complex, segmented fault systems.

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Section: Waveformsmentioning

confidence: 98%

Landers 1992 "reloaded": Integrative dynamic earthquake rupture modeling

Gabriel

Wollherr

Schliwa

et al. 2018

Preprint

View full text Add to dashboard Cite

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“…To capture the effect of seismicity considering all the above-listed controlling factors, the most representative models can be derived via numerical simulations (e.g., Imperatori & Mai, 2015;Lee et al, 2009Lee et al, , 2008. However, such approaches have high computational costs.…”

Section: Reviews Of Geophysicsmentioning

confidence: 99%

Earthquake‐Induced Chains of Geologic Hazards: Patterns, Mechanisms, and Impacts

Fan

Scaringi

Korup

et al. 2019

Reviews of Geophysics

603

325

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Large earthquakes initiate chains of surface processes that last much longer than the brief moments of strong shaking. Most moderate‐ and large‐magnitude earthquakes trigger landslides, ranging from small failures in the soil cover to massive, devastating rock avalanches. Some landslides dam rivers and impound lakes, which can collapse days to centuries later, and flood mountain valleys for hundreds of kilometers downstream. Landslide deposits on slopes can remobilize during heavy rainfall and evolve into debris flows. Cracks and fractures can form and widen on mountain crests and flanks, promoting increased frequency of landslides that lasts for decades. More gradual impacts involve the flushing of excess debris downstream by rivers, which can generate bank erosion and floodplain accretion as well as channel avulsions that affect flooding frequency, settlements, ecosystems, and infrastructure. Ultimately, earthquake sequences and their geomorphic consequences alter mountain landscapes over both human and geologic time scales. Two recent events have attracted intense research into earthquake‐induced landslides and their consequences: the magnitude M 7.6 Chi‐Chi, Taiwan earthquake of 1999, and the M 7.9 Wenchuan, China earthquake of 2008. Using data and insights from these and several other earthquakes, we analyze how such events initiate processes that change mountain landscapes, highlight research gaps, and suggest pathways toward a more complete understanding of the seismic effects on the Earth's surface.

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“…In recent years, significant progress has been made in modeling synthetic ground motions. With the advance of modern computing power, studies such as Bydlon et al (), Graves and Pitarka (), Mai et al (), Taborda et al (), Imperatori and Mai (), Frankel et al (), Wirth et al (), Withers, Olsen, Day, and Shi,(), Withers, Olsen, Shi, and Day, (), Olsen et al (), Graves and Pitarka (), Andrews and Ma (), Hartzell et al (), Pitarka et al (), Pitarka et al (), and Moschetti et al () have incorporated increasingly accurate physics into simulations. Some of these improvements include explicitly accounting for complex rupture processes and the propagation of waves through realistic 3‐D crustal structure to simulate ground motions at a wider range of frequencies for a variety of end‐use cases (from assessing regional seismic hazard related to basin amplification to better understanding the role of anelasticity in nuclear monitoring).…”

Section: Introductionmentioning

confidence: 99%

A Machine Learning Approach to Developing Ground Motion Models From Simulated Ground Motions

Withers

Moschetti

Thompson

2020

Geophysical Research Letters

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We use a machine learning approach to build a ground motion model (GMM) from a synthetic database of ground motions extracted from the Southern California CyberShake study. An artificial neural network is used to find the optimal weights that best fit the target data (without overfitting), with input parameters chosen to match that of state‐of‐the‐art GMMs. We validate our synthetic‐based GMM with empirically based GMMs derived from the globally based Next Generation Attenuation West2 data set, finding near‐zero median residuals and similar amplitude and trends (with period) of total variability. Additionally, we find that the artificial neural network GMM has similar bias and variability to empirical GMMs from records of the recent Mw7.1 Ridgecrest event, which neither GMM has included in its formulation. As simulations continue to better model broadband ground motions, machine learning provides a way to utilize the vast amount of synthetically generated data and guide future parameterization of GMMs.

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The role of topography and lateral velocity heterogeneities on near-source scattering and ground-motion variability

Cited by 59 publications

References 86 publications

Landers 1992 "reloaded": Integrative dynamic earthquake rupture modeling

Landers 1992 "reloaded": Integrative dynamic earthquake rupture modeling

Earthquake‐Induced Chains of Geologic Hazards: Patterns, Mechanisms, and Impacts

A Machine Learning Approach to Developing Ground Motion Models From Simulated Ground Motions

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