Inversion of Love Waves in Earthquake Ground Motion Records for Two-dimensional S-wave Velocity Model of Deep Sedimentary Layers
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.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF.
This is a list of supplementary files associated with this preprint. Click to download.
Posted 09 Dec, 2020
Received 09 Dec, 2020
On 09 Dec, 2020
Invitations sent on 25 Nov, 2020
On 25 Nov, 2020
On 24 Nov, 2020
On 24 Nov, 2020
On 24 Nov, 2020
Posted 22 Sep, 2020
On 12 Jan, 2021
On 24 Oct, 2020
Received 22 Oct, 2020
Received 13 Oct, 2020
On 25 Sep, 2020
On 24 Sep, 2020
Invitations sent on 24 Sep, 2020
On 24 Sep, 2020
On 23 Sep, 2020
On 18 Sep, 2020
On 16 Sep, 2020
Inversion of Love Waves in Earthquake Ground Motion Records for Two-dimensional S-wave Velocity Model of Deep Sedimentary Layers
Posted 09 Dec, 2020
Received 09 Dec, 2020
On 09 Dec, 2020
Invitations sent on 25 Nov, 2020
On 25 Nov, 2020
On 24 Nov, 2020
On 24 Nov, 2020
On 24 Nov, 2020
Posted 22 Sep, 2020
On 12 Jan, 2021
On 24 Oct, 2020
Received 22 Oct, 2020
Received 13 Oct, 2020
On 25 Sep, 2020
On 24 Sep, 2020
Invitations sent on 24 Sep, 2020
On 24 Sep, 2020
On 23 Sep, 2020
On 18 Sep, 2020
On 16 Sep, 2020
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.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF.