Seismic Wave Propagation in Japanese and Large Scale Simulation of Ground Motions

2003 ◽  
Vol 2003.16 (0) ◽  
pp. 987-988
Author(s):  
Takashi FURUMURA
Keyword(s):  
Wave Propagation ◽  
Seismic Wave ◽  
Large Scale ◽  
Ground Motions ◽  
Seismic Wave Propagation ◽  
Large Scale Simulation

Seismic Wave Propagation and Basin Amplification in the Wasatch Front, Utah

2021 ◽  
Author(s):  
Morgan P. Moschetti ◽  
David Churchwell ◽  
Eric M. Thompson ◽  
John M. Rekoske ◽  
Emily Wolin ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Ground Motion ◽  
Seismic Wave ◽  
Seismic Velocity ◽  
Site Response ◽  
Ground Motions ◽  
Seismic Wave Propagation ◽  
Velocity Models ◽  
Ground Motion Variability ◽  
Wasatch Front

Abstract Ground-motion analysis of more than 3000 records from 59 earthquakes, including records from the March 2020 Mw 5.7 Magna earthquake sequence, was carried out to investigate site response and basin amplification in the Wasatch Front, Utah. We compare ground motions with the Bayless and Abrahamson (2019; hereafter, BA18) ground-motion model (GMM) for Fourier amplitude spectra, which was developed on crustal earthquake records from California and other tectonically active regions. The Wasatch Front records show a significantly different near-source rate of distance attenuation than the BA18 model, which we attribute to differences in (apparent) geometric attenuation. Near-source residuals show a period dependence of this effect, with greater attenuation at shorter periods (T<0.5  s) and a correlation between period and the distance over which the discrepancy manifests (∼20–50  km). We adjusted the recorded ground motions for these regional path effects and solved for station site terms using linear mixed-effects regressions, with groupings for events and stations. We analyzed basin amplification by comparing the site terms with the basin geometry and basin depths from two seismic-velocity models for the region. Sites over the deeper parts of the sedimentary basins are amplified by factors of 3–10, relative to sites with thin sedimentary cover, with greater amplification at longer periods (T≳1  s). Average ground-motion variability increases with period, and long-period variability exhibits a slight increase at the basin edges. These results indicate regional seismic wave propagation effects requiring further study, and potentially a regionalized GMM, as well as highlight basin amplification complexities that may be incorporated into seismic hazard assessments.

Simulation of induced seismic ground motions using coupled geomechanical and seismic wave propagation models

2019 ◽  
Author(s):  
Bob Paap ◽  
Dirk Kraaijpoel ◽  
Brecht Wassing ◽  
Jan-Diederik van Wees
Keyword(s):  
Wave Propagation ◽  
Seismic Wave ◽  
Ground Motions ◽  
Moment Tensor ◽  
Seismic Wave Propagation ◽  
Fault Reactivation ◽  
Dynamic Rupture ◽  
Propagation Models ◽  
Earthquake Nucleation ◽  
Spatio Temporal

Summary Numerical simulations of seismic wave propagation usually rely on a simple source model consisting of an idealized point location and a moment tensor. In general, this is a valid approximation when the source dimensions are small relative to the distance of points at which the seismic wave motions are to be evaluated. Otherwise, a more realistic spatio-temporal source representation is required to accurately calculate ground motions at the position of monitoring stations. Here, we present a generic approach to couple geomechanical simulations to seismic wave propagation models using the concept of the equivalent force field. This approach allows the simulation of seismic wave propagation resulting from the spatio-temporal dependent earthquake nucleation and rupture processes. Within the geomechanical package two separate geomechanics codes are used to simulate both the slow loading stage leading to earthquake nucleation as well as the successive dynamic rupture stage. We demonstrate the approach to a case of induced seismicity, where fault reactivation occurs due to production from a natural gas reservoir.

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