Implications of the Mw9.0 Tohoku-Oki Earthquake for Ground Motion Scaling with Source, Path, and Site Parameters

2013 ◽  
Vol 29 (1_suppl) ◽  
pp. 1-21 ◽  
Author(s):  
Jonathan P. Stewart ◽  
Saburoh Midorikawa ◽  
Robert W. Graves ◽  
Khatareh Khodaverdi ◽  
Tadahiro Kishida ◽  
...  
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Site Amplification ◽  
Low Frequencies ◽  
High Frequencies ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Active Tectonic ◽  
Motion Scaling ◽  
Ground Motion Scaling

The Mw9.0 Tohoku-oki Japan earthquake produced approximately 2,000 ground motion recordings. We consider 1,238 three-component accelerograms corrected with component-specific low-cut filters. The recordings have rupture distances between 44 km and 1,000 km, time-averaged shear wave velocities of VS30 = 90 m/s to 1,900 m/s, and usable response spectral periods of 0.01 sec to >10 sec. The data support the notion that the increase of ground motions with magnitude saturates at large magnitudes. High-frequency ground motions demonstrate faster attenuation with distance in backarc than in forearc regions, which is only captured by one of the four considered ground motion prediction equations for subduction earthquakes. Recordings within 100 km of the fault are used to estimate event terms, which are generally positive (indicating model underprediction) at short periods and zero or negative (overprediction) at long periods. We find site amplification to scale minimally with VS30 at high frequencies, in contrast with other active tectonic regions, but to scale strongly with VS30 at low frequencies.

3D Nonlinear Ground‐Motion Simulation Using a Physics‐Based Method for the Kinburn Basin

2019 ◽  
Author(s):  
Amin Esmaeilzadeh ◽  
Dariush Motazedian ◽  
Jim Hunter
Keyword(s):  
Shear Wave ◽  
Ground Motion ◽  
Seismic Waves ◽  
Peak Ground Velocity ◽  
Ground Acceleration ◽  
Low Frequencies ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Nonlinear Viscoelastic ◽  
Finite Fault

Abstract We used a finite‐difference modeling method, developed by Olsen–Day–Cui, to simulate nonlinear‐viscoelastic basin effects in a spectral frequency range of 0.1–1 Hz in the Kinburn bedrock topographic basin, Ottawa, Canada, for large earthquakes. The geotechnical and geological features of the study area are unique: loose, postglacial sediments with very low shear‐wave velocities (<200  m/s) overlying very firm bedrock with high shear‐wave velocities (>2000  m/s). Comparing records and simulated velocity time series showed regular viscoelastic simulations could model the ground motions at the rock and soil sites in the Kinburn basin for the Ladysmith earthquake, a local earthquake occurred on 17 May 2013 with Mw 4.7 (MN 5.2). The Ladysmith earthquake was scaled to provide a strong level of shaking for investigating the nonlinear behavior of soil; therefore, a new nonlinear‐viscoelastic subroutine was introduced to the program. A modeled stress–strain relationship associated with ground‐motion modeling in the Kinburn basin using a scaled Ladysmith earthquake event of Mw 7.5 followed Masing’s rules. Using nonlinear‐viscoelastic ground‐motion simulations significantly reduced the amplitude of the horizontal component of the Fourier spectrum at low frequencies and the predicted peak ground acceleration and peak ground velocity values compared with regular linear viscoelastic simulations; hence, the lower soil amplification of seismic waves and the frequency and amplitude spectral content were altered by the nonlinear soil behavior. In addition, using a finite‐fault model to simulate an earthquake with Mw 7.5 was necessary to predict the higher levels of stresses and strains, which were generated in the basin. Using a finite‐fault source for the nonlinear‐viscoelastic simulation caused decreases in the horizontal components because of the shear modulus reduction and increase of damping.

Semi-Empirical Nonlinear Site Amplification from NGA-West2 Data and Simulations

2014 ◽  
Vol 30 (3) ◽  
pp. 1241-1256 ◽  
Author(s):  
Emel Seyhan ◽  
Jonathan P. Stewart
Keyword(s):  
Ground Motions ◽  
Nonlinear Effects ◽  
Site Amplification ◽  
Site Factors ◽  
Reference Velocity ◽  
Regional Trends ◽  
Motion Scaling ◽  
Ground Motion Scaling ◽  
A Site ◽  
Semi Empirical

We analyze NGA-West2 data and simulations to develop a site amplification model that captures ground motion scaling with V S30 and soil nonlinear effects. We parameterize nonlinearity as the gradient of site amplification with respect to peak acceleration for reference (firm) sites. Both data analyses and simulations indicate nonlinearity for sites with V S30 < 500 m/s and spectral periods T < ∼3 s. Following approximate removal of nonlinear effects from the data, we evaluate V S30-scaling of ground motions, which is most pronounced for T ≥ ∼0.2 s and saturates for hard rock sites. Regional trends in V S30-scaling and nonlinearity were not found to be sufficiently robust to justify inclusion in our model. We apply the site amplification model to derive site factors now approved for building code applications. Principal causes of changes relative to previous values are reduction of the reference velocity (at which amplification is unity) to 760 m/s and reduced nonlinearity.

Simulation-Based Hanging Wall Effects

2014 ◽  
Vol 30 (3) ◽  
pp. 1269-1284 ◽  
Author(s):  
Jennifer L. Donahue ◽  
Norman A. Abrahamson
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Hanging Wall ◽  
Finite Fault ◽  
Simulation Based ◽  
Geometrical Effect ◽  
Motion Scaling ◽  
Ground Motion Scaling ◽  
Rupture Distance ◽  
Source Site

The hanging wall (HW) effect is defined as the increase in ground motion at short distances for sites on the hanging wall side of a rupture when compared to sites on the footwall (FW) side at the same closest distance. In general, it is a geometrical effect due to the use of a closest distance metric, such as rupture distance, that does not capture the main features of the ground motion scaling for sites near dipping faults. To constrain the HW scaling on magnitude, distance, dip, and depth to top of rupture, finite-fault simulations were used to generate ground motions from 34 source geometries with 30 realizations of the slip distribution and hypocenter locations. The scaling of resulting response spectral accelerations at over 130,000 source/site combinations were parameterized to model the dependence of the HW effects. This HW scaling was utilized to constrain some of the NGA-West2 ground motion prediction equations.

scholarly journals Variability of Ground Motion Amplitudes Recorded in Bucharest Area during Vrancea Intermediate-Depth Earthquakes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Florin Pavel
Keyword(s):  
Shear Wave ◽  
Ground Motion ◽  
Site Amplification ◽  
Peak Ground Velocity ◽  
Eurocode 8 ◽  
Intermediate Depth ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Normal Probability ◽  
Normal Probability Distribution

This study focuses on the assessment of the correlation and variability of ground motion amplitudes recorded in Bucharest area during Vrancea intermediate-depth earthquakes from a database of 119 pairs of horizontal components. Empirical models for the evaluation of the peak ground velocity and displacement from spectral accelerations are proposed in this study. The distribution of the shear wave velocities from 41 boreholes at specific depths appears to follow a normal probability distribution. The analysis performed in this study has also shown that the variability of peak ground velocities and displacements does not appear to be influenced by the earthquake magnitude. In addition, it was observed that the variability in terms of shear wave velocities at specific depths is smaller than the variability of the spectral amplitudes of the recorded ground motions. The empirical site-amplification factors from the Eurocode 8 draft fail to capture the long-period spectral amplifications observed in Bucharest area during large magnitude Vrancea intermediate-depth earthquakes.

Testing non-linear amplification factors used in ground motion models

2021 ◽  
Author(s):  
Karina Loviknes ◽  
Danijel Schorlemmer ◽  
Fabrice Cotton ◽  
Sreeram Reddy Kotha
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Ground Motions ◽  
Site Amplification ◽  
Building Codes ◽  
Linear Amplification ◽  
Motion Models ◽  
Earthquake Predictability ◽  
Non Linear ◽  
Ground Motion Models

&lt;p&gt;Non-linear site effects are mainly expected for strong ground motions and sites with soft soils and more recent ground-motion models (GMM) have started to include such effects. Observations in this range are, however, sparse, and most non-linear site amplification models are therefore partly or fully based on numerical simulations. We develop a framework for testing of non-linear site amplification models using data from the comprehensive Kiban-Kyoshin network in Japan. The test is reproducible, following the vision of the Collaboratory for the Study of Earthquake Predictability (CSEP), and takes advantage of new large datasets to evaluate &lt;span&gt;whether or not&lt;/span&gt; non-linear site effects predicted by site-amplification models are supported by empirical data. The site amplification models are tested using residuals between the observations and predictions from a GMM based only on magnitude and distance. When the GMM is derived without any site term, the site-specific variability extracted from the residuals is expected to capture the site response of a site. The non-linear site amplification models are tested against a linear amplification model on individual well-record&lt;span&gt;ing&lt;/span&gt; stations. Finally, the result is compared to building codes where non-linearity is included. The test shows that for most of the sites selected as having sufficient records, the non-linear site-amplification models do not score better than the linear amplification model. This suggests that including non-linear site amplification in GMMs and building codes may not yet be justified, at least not in the range of ground motions considered in the test (peak ground acceleration &lt; 0.2 g).&lt;/p&gt;

scholarly journals Geophysical and geotechnical factors in urban planing: Bursa (Nilüfer, Osmangazi, and Yildirim) cases

2020 ◽  
Author(s):  
Ferhat Özçep ◽  
Guldane Boyraz ◽  
Okan Tezel ◽  
Hakan Alp ◽  
Nuray Alpaslan ◽  
...  
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Earthquake Hazard ◽  
Cyclic Stress ◽  
Soil Liquefaction ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Earthquake Motion ◽  
Potential Index ◽  
Earthquake Hazard Analysis

Abstract. The study area covers the Central of Bursa, Osmangazi, Yildirim, Gürsü, Kestel and Nilüfer District boundaries in Bursa. The seismic process deals with the occurrence of an earthquake event and the process of wave propagation from the source to the site. Local amplification caused by surficial soft soils is a significant factor in destructive earthquake motion. In the first phase of this study, it is investigated the ground motion level and soil amplifications for Bursa city. For his aim, probabilistic and deterministic earthquake hazard analysis (including acceleration estimations) will be carried out for the region. Local amplification caused by surficial soft soils is a significant factor in destructive earthquake motion. In the first phase of this study, it is investigated the ground motion level and soil acharacterization for the region. For his aim, probabilistic earthquake hazard analysis (including acceleration estimations) was carried out for the region. Then, soil shear wave velocities were estimated from data obtained by MASW measurements. Soil liquefaction is a natural event in which the strength and stiffness of a soil are reduced by earthquake vibrations or other dynamic loadings. As it is known, liquefaction occurs in saturated soils, that is, soils in which the space between individual particles is completely filled with water. One of liquefaction evaluation methods is based on the cyclic stress approach. In this method, a safety factor is defined as CRR/CSR. CRR is a cyclic resistance ratio that represents soil liquefaction susceptibility, and CSR is the cyclic stress ratio that represents the earthquake effect. In the second phase of this study, possible soil potential index (PL) and ground induced settlements were estimated by using Isihara ve Yoshimine (1990) approach. All results on liquefaction potential index (Pl), liquefaction induced settlements and soil shear wave velocities in Bursa (Turkey) City were compared with each other. Finally, a seismic microzonation map was prepared by the integration of geophysical and geotechnical data for urban planning purposes.

scholarly journals Evaluation of the Ground Motion Scaling Procedures for Concrete Gravity Dams

2017 ◽  
Vol 199 ◽  
pp. 844-849
Author(s):  
Berat Feyza Soysal ◽  
Bekir Özer Ay ◽  
Yalin Arici
Keyword(s):  
Ground Motion ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Motion Scaling ◽  
Ground Motion Scaling
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