Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms
Abstract A three-dimensional seismic wave speed model in the Kanto region of Japan was developed using adjoint tomography for application in the effective reproduction of observed waveforms. Starting with a model based on previous travel time tomographic results, we inverted the waveforms obtained a...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2017-10-01
|
| Series: | Progress in Earth and Planetary Science |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s40645-017-0143-8 |
| _version_ | 1818113321417572352 |
|---|---|
| author | Takayuki Miyoshi Masayuki Obayashi Daniel Peter Yoko Tono Seiji Tsuboi |
| author_facet | Takayuki Miyoshi Masayuki Obayashi Daniel Peter Yoko Tono Seiji Tsuboi |
| author_sort | Takayuki Miyoshi |
| collection | DOAJ |
| description | Abstract A three-dimensional seismic wave speed model in the Kanto region of Japan was developed using adjoint tomography for application in the effective reproduction of observed waveforms. Starting with a model based on previous travel time tomographic results, we inverted the waveforms obtained at seismic broadband stations from 140 local earthquakes in the Kanto region to obtain the P- and S-wave speeds V p and V s . Additionally, all centroid times of the source solutions were determined before the structural inversion. The synthetic displacements were calculated using the spectral-element method (SEM) in which the Kanto region was parameterized using 16 million grid points. The model parameters V p and V s were updated iteratively by Newton’s method using the misfit and Hessian kernels until the misfit between the observed and synthetic waveforms was minimized. Computations of the forward and adjoint simulations were conducted on the K computer in Japan. The optimized SEM code required a total of 6720 simulations using approximately 62,000 node hours to obtain the final model after 16 iterations. The proposed model reveals several anomalous areas with extremely low-V s values in comparison with those of the initial model. These anomalies were found to correspond to geological features, earthquake sources, and volcanic regions with good data coverage and resolution. The synthetic waveforms obtained using the newly proposed model for the selected earthquakes showed better fit than the initial model to the observed waveforms in different period ranges within 5–30 s. This result indicates that the model can accurately predict actual waveforms. |
| first_indexed | 2024-12-11T03:32:58Z |
| format | Article |
| id | doaj.art-9a70a22b75d844159769c8662e4fdf69 |
| institution | Directory Open Access Journal |
| issn | 2197-4284 |
| language | English |
| last_indexed | 2024-12-11T03:32:58Z |
| publishDate | 2017-10-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Progress in Earth and Planetary Science |
| spelling | doaj.art-9a70a22b75d844159769c8662e4fdf692022-12-22T01:22:20ZengSpringerOpenProgress in Earth and Planetary Science2197-42842017-10-014112010.1186/s40645-017-0143-8Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismogramsTakayuki Miyoshi0Masayuki Obayashi1Daniel Peter2Yoko Tono3Seiji Tsuboi4Earthquake Research Institute, University of TokyoDepartment of Deep Earth Structure and Dynamics Research, Japan Agency for Marine-Earth Science and TechnologyPhysical Sciences and Engineering Division, King Abdullah University of Science and TechnologyResearch and Development Bureau, Ministry of Education, Culture, Sports, Science and TechnologyCenter for Earth Information Science and Technology, Japan Agency for Marine-Earth Science and TechnologyAbstract A three-dimensional seismic wave speed model in the Kanto region of Japan was developed using adjoint tomography for application in the effective reproduction of observed waveforms. Starting with a model based on previous travel time tomographic results, we inverted the waveforms obtained at seismic broadband stations from 140 local earthquakes in the Kanto region to obtain the P- and S-wave speeds V p and V s . Additionally, all centroid times of the source solutions were determined before the structural inversion. The synthetic displacements were calculated using the spectral-element method (SEM) in which the Kanto region was parameterized using 16 million grid points. The model parameters V p and V s were updated iteratively by Newton’s method using the misfit and Hessian kernels until the misfit between the observed and synthetic waveforms was minimized. Computations of the forward and adjoint simulations were conducted on the K computer in Japan. The optimized SEM code required a total of 6720 simulations using approximately 62,000 node hours to obtain the final model after 16 iterations. The proposed model reveals several anomalous areas with extremely low-V s values in comparison with those of the initial model. These anomalies were found to correspond to geological features, earthquake sources, and volcanic regions with good data coverage and resolution. The synthetic waveforms obtained using the newly proposed model for the selected earthquakes showed better fit than the initial model to the observed waveforms in different period ranges within 5–30 s. This result indicates that the model can accurately predict actual waveforms.http://link.springer.com/article/10.1186/s40645-017-0143-8Seismic wave speed modelAdjoint tomographyWaveform inversionBroadband seismogramKanto region |
| spellingShingle | Takayuki Miyoshi Masayuki Obayashi Daniel Peter Yoko Tono Seiji Tsuboi Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms Progress in Earth and Planetary Science Seismic wave speed model Adjoint tomography Waveform inversion Broadband seismogram Kanto region |
| title | Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms |
| title_full | Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms |
| title_fullStr | Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms |
| title_full_unstemmed | Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms |
| title_short | Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms |
| title_sort | adjoint tomography of the crust and upper mantle structure beneath the kanto region using broadband seismograms |
| topic | Seismic wave speed model Adjoint tomography Waveform inversion Broadband seismogram Kanto region |
| url | http://link.springer.com/article/10.1186/s40645-017-0143-8 |
| work_keys_str_mv | AT takayukimiyoshi adjointtomographyofthecrustanduppermantlestructurebeneaththekantoregionusingbroadbandseismograms AT masayukiobayashi adjointtomographyofthecrustanduppermantlestructurebeneaththekantoregionusingbroadbandseismograms AT danielpeter adjointtomographyofthecrustanduppermantlestructurebeneaththekantoregionusingbroadbandseismograms AT yokotono adjointtomographyofthecrustanduppermantlestructurebeneaththekantoregionusingbroadbandseismograms AT seijitsuboi adjointtomographyofthecrustanduppermantlestructurebeneaththekantoregionusingbroadbandseismograms |