scholarly journals A STUDY ON A GENERATION OF SIMULATED EARTHQUAKE GROUND MOTION CONSIDERING PHASE DIFFERENCE CHARACTERISTICS : Part 6 Generation method of simulated earthquake ground motion in terms of Love waves

2007 ◽  
Vol 72 (622) ◽  
pp. 73-82 ◽  
Author(s):  
Takashi YAMANE ◽  
Sumio NAGAHASHI
Keyword(s):  
Ground Motion ◽  
Phase Difference ◽  
Love Waves ◽  
Earthquake Ground Motion

scholarly journals Inversion of Love Waves in Earthquake Ground Motion Records for Two-dimensional S-wave Velocity Model of Deep Sedimentary Layers

2020 ◽  
Author(s):  
Kentaro Kasamatsu ◽  
Hiroaki Yamanaka ◽  
Shin’ichi Sakai
Keyword(s):  
Ground Motion ◽  
Wave Velocity ◽  
Velocity Structure ◽  
Principal Component ◽  
Love Waves ◽  
Earthquake Ground Motion ◽  
Inversion Method ◽  
S Wave ◽  
Near Surface ◽  
Strong Ground Motion Prediction

Abstract We have proposed a new waveform inversion method to estimate a 2D S-wave velocity structure of deep sedimentary layers using broadband Love waves. As a preprocessing operation in our inversion scheme, we decompose earthquake observation records into velocity waveforms at periods of 1 s interval. Then, we verify an assumption of 2D propagations of Love waves with polarization features based on a principal component analysis to select the segments applied for the inversion. A linearized iterative inversion analysis for the selected Love wave segments filtered at period of every 1 s allows a detailed estimation of boundary shapes of interfaces over the seismic bedrock with an S-wave velocity of approximately 3 km/s. We demonstrate the technique’s effectiveness with applications to observed seismograms in the Kanto plain, Japan. Differences between the estimated and existing structural models are remarkable at basin edges. A regional variation of the near-surface S-wave velocities in our model is similar to a distribution of surface geological classifications. Since a subsurface structure at a basin edge strongly affects earthquake ground motions in a basin with generations of surface waves, our method can provide a detail model of a complex S-wave velocity structure at an edge part for a strong ground motion prediction.

scholarly journals Inversion of Love waves in earthquake ground motion records for two-dimensional S-wave velocity model of deep sedimentary layers

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Kentaro Kasamatsu ◽  
Hiroaki Yamanaka ◽  
Shin’ichi Sakai
Keyword(s):  
Ground Motion ◽  
Wave Velocity ◽  
Velocity Structure ◽  
Principal Component ◽  
Love Waves ◽  
Earthquake Ground Motion ◽  
Inversion Method ◽  
S Wave ◽  
Detailed Model ◽  
Strong Ground Motion Prediction

AbstractWe propose a new waveform inversion method to estimate the 2D S-wave velocity structure of deep sedimentary layers using broadband Love waves. As a preprocessing operation in our inversion scheme, we decompose earthquake observation records into velocity waveforms for periods of 1 s each. Then, we include in the inversion only those periods for which the assumption of 2D propagation holds, which we propose to determine through a principal component analysis. A linearized iterative inversion analysis for the selected Love wave segments filtered for periods of 1 s each allows a detailed estimation of the boundary shapes of interfaces over the seismic bedrock with an S-wave velocity of approximately 3 km/s. We demonstrate the effectiveness of the technique with applications to observed seismograms in the Kanto Plain, Japan. The differences between the estimated and existing velocity structure models are remarkable at the basin edges. Our results show remarkable differences from previous existing structural models, particularly near the basin edges while being in good agreement with the surface geology. Since a subsurface structure at a basin edge strongly affects the earthquake ground motions in a basin with the generation of surface waves, our method can provide a detailed model of a complex S-wave velocity structure at an edge part for strong ground motion prediction.

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