The effect of lateral variations of friction on crustal faulting
We propose that lateral variations in fault friction control the heterogeneity of slip observed in large earthquakes, We model these variations using a rate and state-dependent friction law, where we differentiate velocity-weakening into strong and weak-seismic fields, and velocity-strengthening int...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
1994-06-01
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| Series: | Annals of Geophysics |
| Subjects: | |
| Online Access: | http://www.annalsofgeophysics.eu/index.php/annals/article/view/4142 |
| _version_ | 1818084048714596352 |
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| author | M. Cocco J. Boatwright |
| author_facet | M. Cocco J. Boatwright |
| author_sort | M. Cocco |
| collection | DOAJ |
| description | We propose that lateral variations in fault friction control the heterogeneity of slip observed in large earthquakes, We model these variations using a rate and state-dependent friction law, where we differentiate velocity-weakening into strong and weak-seismic fields, and velocity-strengthening into compliant and viscous fields. The strong-seismic field comprises the seismic slip concentrations, or asperities. The two «intermediate» frictional fields, weak-seismic and compliant, modulate both the tectonic loading and the dynamic rupture process. During the interseismic period, the compliant and viscous regions slip aseismically while the strong-seismic regions remain locked, evolving into stress concentrations that fail only in main shocks. The weak-seismic regions contain most of the interseismic activity and aftershocks, but also «creep seismically», that is, most of the weak-seismic area slips aseismically, actuating the seismicity on the remaining area. This «mixed» frictional behavior can be obtained from a sufficiently heterogenous distribution for the critical slip distance. The interseismic slip provides an inherent rupture resistance: dynamic rupture fronts decelerate as they penetrate into these unloaded compliant or creeping weak-seismic areas, diffusing into broad areas of accelerated afterslip. Aftershocks occur in both the weak-seismic and compliant areas around the fault, but most of the stress is diffused through aseismic slip. Rapid afterslip on these peripheral areas can also produce aftershocks within the main shock rupture area, by reloading weak fault areas that slipped in the main shock and then healed. We test this frictional model by comparing the interevent seismicity and aftershocks to the coseismic slip distribution for the 1966 Parkfield, 1979 Coyote Lake, and 1984 Morgan Hill earthquakes. |
| first_indexed | 2024-12-10T19:47:42Z |
| format | Article |
| id | doaj.art-01e54aef537b4fcfa0ca98e7ba39e574 |
| institution | Directory Open Access Journal |
| issn | 1593-5213 2037-416X |
| language | English |
| last_indexed | 2024-12-10T19:47:42Z |
| publishDate | 1994-06-01 |
| publisher | Istituto Nazionale di Geofisica e Vulcanologia (INGV) |
| record_format | Article |
| series | Annals of Geophysics |
| spelling | doaj.art-01e54aef537b4fcfa0ca98e7ba39e5742022-12-22T01:35:51ZengIstituto Nazionale di Geofisica e Vulcanologia (INGV)Annals of Geophysics1593-52132037-416X1994-06-0137610.4401/ag-4142The effect of lateral variations of friction on crustal faultingM. CoccoJ. BoatwrightWe propose that lateral variations in fault friction control the heterogeneity of slip observed in large earthquakes, We model these variations using a rate and state-dependent friction law, where we differentiate velocity-weakening into strong and weak-seismic fields, and velocity-strengthening into compliant and viscous fields. The strong-seismic field comprises the seismic slip concentrations, or asperities. The two «intermediate» frictional fields, weak-seismic and compliant, modulate both the tectonic loading and the dynamic rupture process. During the interseismic period, the compliant and viscous regions slip aseismically while the strong-seismic regions remain locked, evolving into stress concentrations that fail only in main shocks. The weak-seismic regions contain most of the interseismic activity and aftershocks, but also «creep seismically», that is, most of the weak-seismic area slips aseismically, actuating the seismicity on the remaining area. This «mixed» frictional behavior can be obtained from a sufficiently heterogenous distribution for the critical slip distance. The interseismic slip provides an inherent rupture resistance: dynamic rupture fronts decelerate as they penetrate into these unloaded compliant or creeping weak-seismic areas, diffusing into broad areas of accelerated afterslip. Aftershocks occur in both the weak-seismic and compliant areas around the fault, but most of the stress is diffused through aseismic slip. Rapid afterslip on these peripheral areas can also produce aftershocks within the main shock rupture area, by reloading weak fault areas that slipped in the main shock and then healed. We test this frictional model by comparing the interevent seismicity and aftershocks to the coseismic slip distribution for the 1966 Parkfield, 1979 Coyote Lake, and 1984 Morgan Hill earthquakes.http://www.annalsofgeophysics.eu/index.php/annals/article/view/4142frictionfaultingaftershocksaseismic slip |
| spellingShingle | M. Cocco J. Boatwright The effect of lateral variations of friction on crustal faulting Annals of Geophysics friction faulting aftershocks aseismic slip |
| title | The effect of lateral variations of friction on crustal faulting |
| title_full | The effect of lateral variations of friction on crustal faulting |
| title_fullStr | The effect of lateral variations of friction on crustal faulting |
| title_full_unstemmed | The effect of lateral variations of friction on crustal faulting |
| title_short | The effect of lateral variations of friction on crustal faulting |
| title_sort | effect of lateral variations of friction on crustal faulting |
| topic | friction faulting aftershocks aseismic slip |
| url | http://www.annalsofgeophysics.eu/index.php/annals/article/view/4142 |
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