Origin of the Co‐Seismic Variations of Elastic Properties in the Crust: Insight From the Laboratory
| Autor: | Paglialunga, F., Passelègue, F. X., Acosta, M., Violay, M. |
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| Rok vydání: | 2021 |
| Předmět: |
Informatics
010504 meteorology & atmospheric sciences Earthquake Source Observations Fault (geology) Wave Attenuation 010502 geochemistry & geophysics 01 natural sciences Acoustic Properties Ionospheric Physics Petrology Seismology Earthquake Interaction Forecasting and Prediction Exploration Geophysics Gravity Methods Seismic properties geography.geographical_feature_category Ocean Predictability and Prediction Seismic Cycle Related Deformations Tectonic Deformation Oceanography: General Policy Geophysics Amplitude Time Variable Gravity Estimation and Forecasting Seismicity and Tectonics Space Weather Mathematical Geophysics Triaxial compression Probabilistic Forecasting Geology Damage zone Friction Dynamic rupture Satellite Geodesy: Results Radio Science Stress (mechanics) Earthquake Dynamics Fault gouge Research Letter Magnetospheric Physics Geodesy and Gravity Ionosphere Monitoring Forecasting Prediction Physical Properties of Rocks Solid Earth 0105 earth and related environmental sciences Gravity anomalies and Earth structure Continental Crust geography Faulting Crust Policy Sciences Interferometry 13. Climate action General Earth and Planetary Sciences Dilation (morphology) Ultrasonic sensor Subduction Zones Hydrology Transient Deformation Prediction Natural Hazards Forecasting |
| Zdroj: | Geophysical Research Letters |
| ISSN: | 1944-8007 0094-8276 |
| DOI: | 10.1029/2021gl093619 |
| Popis: | Seismological observations highlighted that earthquakes are often followed by changes in elastic properties around the fault zone. Here, we studied the origin of these variations using stick‐slip experiments on saw‐cut granite samples presenting different degrees of bulk damage (i.e., microcracks). Stick‐slip events were induced under triaxial compression configuration with continuous active ultrasonic measurements at confining pressures representative of upper crustal conditions (15–120 MPa). Both the P‐wave velocity (VP) and amplitude (AP) showed drops, concurrently with stress drops, and had a non‐monotonic dependence toward the fault's stress state. Our experimental results suggest that co‐seismic changes in VP were mostly controlled by the elastic re‐opening of microcracks in the bulk, rather than by co‐seismic damage or the formation of fault gouge. Co‐seismic changes in AP were controlled by a combination of elastic re‐opening of microcracks in the bulk and inelastic processes (i.e., co‐seismic damage and gouge formation and dilation). Key Points Laboratory earthquakes are associated with seismic velocity and amplitude drops in crustal rocksVelocity drops are controlled by the stress acting on the fault and degree of damage in the fault wallAmplitude drops are partly controlled by the state of stress and partly affected by dissipative (inelastic) phenomena occurring on‐fault |
| Databáze: | OpenAIRE |
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