Estimating Effective Normal Stress During Slow Slip Events From Slip Velocities and Shear Stress Variations
Abstract Theoretical analyses using a rate‐ and state‐dependent friction law have shown quasistatic and stable slip behaviors following velocity weakening. We estimated spatiotemporal slip distributions for six slow slip events (SSEs) off the Boso Peninsula, Japan, from Global Navigation Satellite S...
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| Format: | Article |
| Language: | English |
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Wiley
2021-10-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2021GL095690 |
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| author | Takuma Kobayashi Toshinori Sato |
| author_facet | Takuma Kobayashi Toshinori Sato |
| author_sort | Takuma Kobayashi |
| collection | DOAJ |
| description | Abstract Theoretical analyses using a rate‐ and state‐dependent friction law have shown quasistatic and stable slip behaviors following velocity weakening. We estimated spatiotemporal slip distributions for six slow slip events (SSEs) off the Boso Peninsula, Japan, from Global Navigation Satellite System data and plotted their shear stress variations vs. slip velocity, here called “trajectories.” Most trajectories are similar to theoretical stable trajectories, implying that the Boso SSEs represent a quasistatic and stable process, and that the gradient of the trajectories during slip acceleration is equal to the product of the friction coefficients of the slipping plates (a–b) and the effective normal stress (σn′). Taking (a–b) = −0.003, we estimate that the effective normal stresses during the SSEs were 10–50 MPa at 12.5–20.5 km depth. These values are much smaller than the lithostatic pressures at those depths, implying high pore pressures on the slow slip interface. |
| format | Article |
| id | doaj-art-abd807d1740d474885be2af901129cd8 |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2021-10-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-abd807d1740d474885be2af901129cd82025-08-20T03:22:14ZengWileyGeophysical Research Letters0094-82761944-80072021-10-014820n/an/a10.1029/2021GL095690Estimating Effective Normal Stress During Slow Slip Events From Slip Velocities and Shear Stress VariationsTakuma Kobayashi0Toshinori Sato1Graduate School of Science Chiba University Chiba JapanGraduate School of Science Chiba University Chiba JapanAbstract Theoretical analyses using a rate‐ and state‐dependent friction law have shown quasistatic and stable slip behaviors following velocity weakening. We estimated spatiotemporal slip distributions for six slow slip events (SSEs) off the Boso Peninsula, Japan, from Global Navigation Satellite System data and plotted their shear stress variations vs. slip velocity, here called “trajectories.” Most trajectories are similar to theoretical stable trajectories, implying that the Boso SSEs represent a quasistatic and stable process, and that the gradient of the trajectories during slip acceleration is equal to the product of the friction coefficients of the slipping plates (a–b) and the effective normal stress (σn′). Taking (a–b) = −0.003, we estimate that the effective normal stresses during the SSEs were 10–50 MPa at 12.5–20.5 km depth. These values are much smaller than the lithostatic pressures at those depths, implying high pore pressures on the slow slip interface.https://doi.org/10.1029/2021GL095690Slow slip eventseffective normal stressquasistatic and stable slip behaviorhigh pore pressureoff the Boso Peninsula |
| spellingShingle | Takuma Kobayashi Toshinori Sato Estimating Effective Normal Stress During Slow Slip Events From Slip Velocities and Shear Stress Variations Geophysical Research Letters Slow slip events effective normal stress quasistatic and stable slip behavior high pore pressure off the Boso Peninsula |
| title | Estimating Effective Normal Stress During Slow Slip Events From Slip Velocities and Shear Stress Variations |
| title_full | Estimating Effective Normal Stress During Slow Slip Events From Slip Velocities and Shear Stress Variations |
| title_fullStr | Estimating Effective Normal Stress During Slow Slip Events From Slip Velocities and Shear Stress Variations |
| title_full_unstemmed | Estimating Effective Normal Stress During Slow Slip Events From Slip Velocities and Shear Stress Variations |
| title_short | Estimating Effective Normal Stress During Slow Slip Events From Slip Velocities and Shear Stress Variations |
| title_sort | estimating effective normal stress during slow slip events from slip velocities and shear stress variations |
| topic | Slow slip events effective normal stress quasistatic and stable slip behavior high pore pressure off the Boso Peninsula |
| url | https://doi.org/10.1029/2021GL095690 |
| work_keys_str_mv | AT takumakobayashi estimatingeffectivenormalstressduringslowslipeventsfromslipvelocitiesandshearstressvariations AT toshinorisato estimatingeffectivenormalstressduringslowslipeventsfromslipvelocitiesandshearstressvariations |