1 / 25

Kenji MAEDA Meteorological Research Institute, JMA

This study aims to estimate fault constitutive parameter Aσ and stress accumulation rate from seismicity response to a large earthquake. Techniques involve analyzing seismicity data to determine stress changes and rates. The research focuses on areas unaffected by earthquake slip inhomogeneity to accurately assess stress change. The study applies Dieterich's (1994) method to evaluate seismicity response post-stress step and employs Omori's formula for rate change analysis. The investigation covers space-time distribution and cumulative data of the 2003 Tokachi-oki earthquake (M8.0), utilizing declustered seismicity information. Stress change is evaluated through GPS data on horizontal movement and baseline length variations. Results provide valuable insights into post-earthquake stress dynamics.

aharn
Download Presentation

Kenji MAEDA Meteorological Research Institute, JMA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Estimation of the Fault Constitutive Parameter Aσ and Stress Accumulation Rate from Seismicity Response to a Large Earthquake Kenji MAEDA Meteorological Research Institute, JMA

  2. Objectives • Estimate the fault constitutive parameter Aσ from the seismicity response to a large earthquake. • Estimate the stress accumulation rate from the seismicity response to a large earthquake. • Estimate the stress change from seismicity data.

  3. Seismicity rate after the stress step Dieterich(1994)

  4. Seismicity rate after the stress step Dieterich(1994)

  5. Stress Step & Seismicity Rate Change

  6. When we select the target area to apply the method, we pay attention to • The fault model of a large earthquake is well determined. • The seismicity rate change caused by a stress step is clearly recognized. • The area is far enough from a large earthquake not to be effected by a slip inhomogeneity of the earthquake. • The rate change tend to follow Omori’s formula.

  7. dCFF by the 2003 Tokachi-oki Eq. 0.07~0.16MPa

  8. Seismicity in Hokkaido

  9. Space-Time Distribution of Eqs. D C B A 2003 Tokachi-oki Eq. (M8.0)

  10. Investigated Regions A B D C

  11. Region A (No decluster) Space-Time 2003 Tokachi-oki Eq. (M8.0) Depth-Time Cumulative

  12. Space Space Connection Distance Cluster 1 Connection Time Cluster 2 Time Time Declustering Algorithm

  13. Region A (Decluster 1km,1day) Space-Time 2003 Tokachi-oki Eq. (M8.0) Depth-Time Cumulative

  14. Region C (No Decluster) Space-Time 2003 Tokachi-oki Eq. (M8.0) Depth-Time Cumulative

  15. Region C (Decluster 3km,7day) Space-Time 2003 Tokachi-oki Eq. (M8.0) Depth-Time Cumulative

  16. Fitness of (Modi-)Omori Form.

  17. Obtaining Stress Change from Seismicity Rate Change Dieterich(2000)

  18. Declustered Seismicity Change and Estimated Stress

  19. Teshio Shintoku2 Horizontal Movement (1/1/03~2/28/05） GPS data from GSI

  20. Baseline Length Change Between Teshio and Shintoku2 基線長変化 GPS data from GSI Estimated Stress Change in region A Baseline Length and Estimated Stress

  21. Estimated Values

  22. Estimated Values

  23. Non-declustered Seismicity Estimated Stress Non-declustered Seismicity Change and Estimated Stress

  24. Summary • The fault constitutive parameter Aσ is estimated from the declustered seismicity that is activated by a large earthquake. • The reference stress accumulation rate is also estimated by assuming no large stress change followed the mainshock. • The time variation of stress is estimated from the seismicity rate change by using estimated Aσ and stress accumulation rate .

More Related