| Autor: |
Bianchi, Patrick, Selvadurai, Paul Antony, Salazar Vasquez, Antonio, Dal Zilio, Luca, Madonna, Claudio, Gerya, Taras, Wiemer, Stefan |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Popis: |
Due to the difficulty to retrieve direct measurements and observations in the field, we use laboratory and numerical models to study and better understand localization processes prior to mainshocks. We use a triaxial machine (LabQuake) to perform a failure test on an intact sample of Berea sandstone confined at 20 MPa. Employing in-house developed conical-type piezo- electric transducers (PZT), which are absolutely calibrated and exhibit a flat and broadband response between 100 kHz and 1.5 MHz, we are able to investigate the acoustic emission (AE) clouds by relocating the single events and by computing their focal mechanisms and scalar seismic moments. The PZT sensors are also used actively to account for velocity and anisotropy changes in the sample during the test. Further, we capture the heterogeneous spatial distribution of the surface strain field by deploying fiber optics cables on the sample surface. All these measurements are used to validate numerical simulations of the experiment using a two- dimensional continuum-based and fully coupled seismo-hydro-mechanical poro-visco-elasto- plastic modelling tool (H-MEC). By combining laboratory observations with numerical models, we are able to study physical mechanisms (e.g., viscous compaction of pores and rock damage) which potentially explain the observed localization processes that produces both acoustic emissions and surface strain concentrations occurring prior to the main fracture of the sample. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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