scholarly journals RETRACTED ARTICLE: Estimation of the source process and forward simulation of long-period ground motion of the 2018 Hokkaido Eastern Iburi, Japan, earthquake

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Hisahiko Kubo ◽  
Asako Iwaki ◽  
Wataru Suzuki ◽  
Shin Aoi ◽  
Haruko Sekiguchi
Keyword(s):  
Ground Motion ◽  
Velocity Structure ◽  
Time Window ◽  
Waveform Inversion ◽  
Strong Motion ◽  
Source Model ◽  
Multiple Time ◽  
Velocity Models ◽  
Long Period ◽  
Slip Area

Abstract In this study, we investigate the source rupture process of the 2018 Hokkaido Eastern Iburi earthquake in Japan (MJMA 6.7) and how the ground motion can be reproduced using available source and velocity models. First, we conduct a multiple-time-window kinematic waveform inversion using strong-motion waveforms, which indicates that a large-slip area located at a depth of 25–30 km in the up-dip direction from the hypocenter was caused by a rupture propagating upward 6–12 s after its initiation. Moreover, the high-seismicity area of aftershocks did not overlap with the large-slip area. Subsequently, using the obtained source model and a three-dimensional velocity structure model, we conduct a forward long-period (< 0.5 Hz) ground-motion simulation. The simulation was able to reproduce the overall ground-motion characteristics in the sedimentary layers of the Ishikari Lowland.

Cluster Analysis of the Long-Period Ground-Motion Simulation Data: Application of the Sagami Trough Megathrust Earthquake Scenarios

2019 ◽  
Vol 14 (3) ◽  
pp. 435-444
Author(s):  
Takahiro Maeda ◽  
Hiroyuki Fujiwara ◽  
Sho Akagi ◽  
Toshihiko Hayakawa ◽  
◽  
...  
Keyword(s):  
Ground Motion ◽  
Velocity Structure ◽  
Strong Motion ◽  
Structure Model ◽  
Earthquake Scenario ◽  
Earthquake Scenarios ◽  
Sagami Trough ◽  
Long Period ◽  
Long Period Ground Motion ◽  
The Relationship

A clustering method that classifies earthquake scenarios and the local area on the basis of similarities in the spatial distribution of ground motion was applied to long-period ground-motion data computed by a seismic wave propagation simulation. The simulation utilized a large number of seismic source models and a three-dimensional velocity structure model in which megathrust earthquakes in the Sagami Trough were assumed. The relationship between the clusters, earthquake scenario parameters, and the velocity structure model was examined. In addition, the relationship between the earthquake scenario clusters for a case in which actual strong-motion observation points were treated as a mesh and those for a case in which an entire set of meshes was investigated, and a spatial interpolation method that estimated a ground-motion distribution from strong-motion observation data was examined.

Shallow velocity structure and poisson's ratio at the Tarzana, California, strong-motion accelerometer site

1996 ◽  
Vol 86 (6) ◽  
pp. 1704-1713 ◽  
Author(s):  
R. D. Catchings ◽  
W. H. K. Lee
Keyword(s):  
Urban Areas ◽  
Velocity Structure ◽  
Strong Motion ◽  
P Wave ◽  
S Wave ◽  
Near Surface ◽  
Velocity Models ◽  
Wave Velocities ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Abstract The 17 January 1994, Northridge, California, earthquake produced strong ground shaking at the Cedar Hills Nursery (referred to here as the Tarzana site) within the city of Tarzana, California, approximately 6 km from the epicenter of the mainshock. Although the Tarzana site is on a hill and is a rock site, accelerations of approximately 1.78 g horizontally and 1.2 g vertically at the Tarzana site are among the highest ever instrumentally recorded for an earthquake. To investigate possible site effects at the Tarzana site, we used explosive-source seismic refraction data to determine the shallow (&lt;70 m) P-and S-wave velocity structure. Our seismic velocity models for the Tarzana site indicate that the local velocity structure may have contributed significantly to the observed shaking. P-wave velocities range from 0.9 to 1.65 km/sec, and S-wave velocities range from 0.20 and 0.6 km/sec for the upper 70 m. We also found evidence for a local S-wave low-velocity zone (LVZ) beneath the top of the hill. The LVZ underlies a CDMG strong-motion recording site at depths between 25 and 60 m below ground surface (BGS). Our velocity model is consistent with the near-surface (&lt;30 m) P- and S-wave velocities and Poisson's ratios measured in a nearby (&lt;30 m) borehole. High Poisson's ratios (0.477 to 0.494) and S-wave attenuation within the LVZ suggest that the LVZ may be composed of highly saturated shales of the Modelo Formation. Because the lateral dimensions of the LVZ approximately correspond to the areas of strongest shaking, we suggest that the highly saturated zone may have contributed to localized strong shaking. Rock sites are generally considered to be ideal locations for site response in urban areas; however, localized, highly saturated rock sites may be a hazard in urban areas that requires further investigation.

Development of a New Method of Baseline Correction on Earthquake Strong Motions and Its Application to Long Period Sloshing Responses of Liquid Storage Tanks During Strong Earthquakes

2003 ◽  
Author(s):  
Chikahiro Minowa
Keyword(s):  
Ground Motion ◽  
Low Frequency ◽  
Strong Motion ◽  
Correction Method ◽  
New Method ◽  
Baseline Correction ◽  
Storage Tanks ◽  
Low Frequencies ◽  
Long Period ◽  
Liquid Storage

In this paper, a new method of baseline correction on strong motion acceleration records is presented and the fundamental concept for baseline corrections on the earthquake strong motions is described. Considering the filtering effect, the earthquakes ground motion displacements of 1995 JMA KOBE, 1999 Kocaeli YPT and 1999 Chi-Chi TCU068 are discussed. Also, the linear sloshing responses of large liquid tanks subjected to these motions were discussed. Since liquid storage tanks show the low frequency (long period) sloshing characteristics and the strong motion characteristics of 1999 Kocaeli and Chi-Chi earthquakes are also low frequencies and large permanent displacements, the sloshing responses in large liquid tanks, especially in long natural periods, were significantly affected by the low frequency motions (large permanent displacements) of these devastating earthquakes. It is very important to use suitable ground motion characterized low frequency content for earthquake resistant design of liquid storage tanks. The baseline correction method presented in the paper may be adequately used to correct strong motion records for large liquid storage design.

Improvement of the objective function in the velocity structure inversion based on horizontal-to-vertical spectral ratio of earthquake ground motions

2020 ◽  
Vol 224 (1) ◽  
pp. 1-16
Author(s):  
Mianshui Rong ◽  
Xiaojun Li ◽  
Lei Fu
Keyword(s):  
Objective Function ◽  
Ground Motion ◽  
Velocity Structure ◽  
Strong Motion ◽  
Earthquake Ground Motion ◽  
Inversion Method ◽  
Observation Data ◽  
S Wave ◽  
Inversion Methods ◽  
Underground Velocity Structures

SUMMARY Given the improvements that have been made in the forward calculations of seismic noise horizontal-to-vertical spectral ratios (NHVSRs) or earthquake ground motion HVSRs (EHVSRs), a number of HVSR inversion methods have been proposed to identify underground velocity structures. Compared with the studies on NHVSR inversion, the research on the EHVSR-based inversion methods is relatively rare. In this paper, to make full use of the widely available and constantly accumulating strong-motion observation data, we propose an S-wave HVSR inversion method based on diffuse-field approximation. Herein, the S-wave components of earthquake ground motion recordings are considered as data source. Improvements to the objective function has been achieved in this work. An objective function with the slope term is introduced. The new objective function can mitigate the multisolution phenomenon encountered when working with HVSR curves with multipeaks. Then, a synthetic case is used to show the verification of the proposed method and this method has been applied to invert underground velocity structures for six KiK-net stations based on earthquake observations. The results show that the proposed S-wave EHVSR inversion method is effective for identifying underground velocity structures.

scholarly journals Long-Period Ground Motion Simulation Based on Three-dimensional Centroid Moment Tensor Inversion Solutions in the Kanto Region, Japan

2020 ◽  
Author(s):  
Shunsuke Takemura ◽  
Kazuo Yoshimoto ◽  
Katsuhiko Shiomi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Moment Tensor ◽  
Three Dimensional ◽  
Centroid Moment Tensor ◽  
Velocity Models ◽  
Long Period ◽  
Ground Motion Simulations ◽  
Kanto Basin ◽  
Long Period Ground Motion

Abstract We conducted centroid moment tensor (CMT) inversions of moderate (Mw 4.5–6.5) earthquakes in the Kanto region, Japan, using a local three-dimensional (3D) model. We then investigated the effects of our 3D CMT solutions on long-period ground motion simulations. Grid search CMT inversions were conducted using displacement seismograms for periods of 25–100 s. By comparing our 3D CMT solutions with those from the local one-dimensional (1D) catalog, we found that our 3D CMT inversion systematically provides magnitudes smaller than those in the 1D catalog. The Mw differences between 3D and 1D catalogs tend to be significant for earthquakes within the oceanic slab. By comparing ground motion simulations between 1D and 3D velocity models, we confirmed that observed Mw differences could be explained by differences in the rigidity structures around the source regions between 3D and 1D velocity models. The 3D velocity structures (especially oceanic crust and mantle) are important for estimating seismic moments in intraslab earthquakes. The seismic moments directly affect the amplitudes of ground motions. Thus, 3D CMT solutions are essential for the precise forward and inverse modeling of long-period ground motion. We also conducted long-period ground motion simulations using our 3D CMT solutions to evaluate reproducibility of long-period ground motions at stations within the Kanto Basin. The simulations of our 3D CMT inversion well-reproduced observed ground motions for periods longer than 10 s, even at stations within the Kanto Basin.

Exploration of Deep S-Wave Velocity Structure in Niigata and Shonai Plains to Estimate Long-period Earthquake Ground Motion

2009 ◽  
Vol 61 (4) ◽  
pp. 191-205
Author(s):  
Hiroaki SATO ◽  
Hiroaki YAMANAKA ◽  
Sadanori HIGASHI ◽  
Kiyotaka SATO ◽  
Yoshiaki SHIBA ◽  
...  
Keyword(s):  
Ground Motion ◽  
Wave Velocity ◽  
Velocity Structure ◽  
Earthquake Ground Motion ◽  
S Wave ◽  
Long Period

3-D joint geodetic and strong-motion finite fault inversion of the 2008 May 12, Wenchuan, China Earthquake

2020 ◽  
Vol 222 (2) ◽  
pp. 1390-1404
Author(s):  
Leonardo Ramirez-Guzman ◽  
Stephen Hartzell
Keyword(s):  
Time Window ◽  
Joint Inversion ◽  
Strong Motion ◽  
Multiple Time ◽  
Source Inversion ◽  
Geodetic Inversion ◽  
Finite Fault Inversion ◽  
Finite Fault ◽  
China Earthquake ◽  
The Moment

SUMMARY We present a source inversion of the 2008 Wenchuan, China earthquake, using strong-motion waveforms and geodetic offsets together with 3-D synthetic ground motions. We applied the linear multiple time window technique considering geodetic and dynamic Green's functions computed with the finite-element method and the reciprocity and Strain Green's Tensor formalism. All ground motion estimates, valid up to 1 Hz, accounted for 3-D effects, including the topography and the geometry of the Beichuan and Pengguan faults. Our joint inversion has a higher moment (M0) than a purely geodetic inversion and the slip distribution presents differences when compared to 1-D model source inversions. The moment is estimated to be M0 = 1.2 × 1021 N·m, slightly larger than other works. Our results show that considering a complex 3-D structure reduces the size of large areas of 10 m slip or greater by distributing it in wider zones, with reduced slips, in the central portion of the Beichuan and the Pengguan faults. Finally, we compare our source with a relocated aftershock catalogue and conclude that the 4–5 m slip contours approximately bound the absence or presence of aftershocks.

A Ground Motion Prediction Model for Deep Earthquakes beneath the Island of Hawaii

2015 ◽  
Vol 31 (3) ◽  
pp. 1763-1788 ◽  
Author(s):  
Ivan G. Wong ◽  
Walter J. Silva ◽  
Robert Darragh ◽  
Nick Gregor ◽  
Mark Dober
Keyword(s):  
Prediction Model ◽  
Ground Motion ◽  
Strong Motion ◽  
Nonlinear Least Squares ◽  
Source Model ◽  
Motion Prediction ◽  
Ground Motion Prediction ◽  
Motion Data ◽  
Ground Motion Model ◽  
Stress Drops

Until recently, no ground motion prediction model was available for deep ( >20 km) Hawaiian earthquakes, including the 2006 M6.7 Kiholo Bay earthquake. We developed such a model based on the stochastic point-source model. Strong motion data from the 2006 event and 15 other deep Hawaiian earthquakes of M3.3 to M6.2 were inverted using a nonlinear least-squares inversion of Fourier amplitude spectra to estimate stress drops for input into the stochastic modeling and for the few larger events (M ≥ 5.0), to calibrate the ground motion prediction model. The ground motion model is valid for M3.5 to M7.5 over the Joyner-Boore ( RJB) distance range of 20 km to 400 km and are for 5%-damped horizontal spectral acceleration at 27 periods from PGA (0.01 s) to 10.0 s. The shallow site condition assumed for the model is soil and weathered basalt with a mean VS30 of 428 m/s.

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