Descripción del proyecto
Un estudio más detallado de las fracturas de rocas antes y durante terremotos
La capacidad de predecir con exactitud el momento, la ubicación y la magnitud de futuros terremotos sigue siendo limitada. Sin embargo, el equipo del proyecto BREAK, financiado por el Consejo Europeo de Investigación, revolucionará el ámbito de la mecánica de terremotos. Para ello, se investigará si la deformación de la corteza terrestre se localiza en fallas que, o bien pueden romperse rápidamente y originar terremotos, o bien sufrir un deslizamiento asísmico lento. En concreto, los investigadores del proyecto aportarán las primeras observaciones cuantitativas experimentales del campo de desplazamiento completo en rocas antes y durante el deslizamiento de la falla y, además, identificarán los componentes asísmicos y sísmicos de este proceso. En el proyecto se desarrollarán técnicas experimentales novedosas basadas sobre todo en la obtención simultánea de imágenes de microtomografía de rayos X dinámica y de sincrotrón, así como en la obtención y el análisis de datos de emisiones acústicas.
Objetivo
Deformation in Earth’s crust localizes onto faults that may rupture rapidly producing earthquakes or undergo slow aseismic slip. The detailed mechanisms that control the transition between the seismic and aseismic regimes and the onset of earthquakes remain unknown. These mechanisms control the geophysical processes preceding catastrophic failure, such as fracture development and strain localization on faults and in the rock volumes surrounding them. Our goal is to provide the first quantitative laboratory observations of the full displacement field in rocks before and during fault slip, and separate the aseismic and seismic components of it. We will develop novel experimental techniques based primarily on simultaneous dynamic synchrotron X-ray microtomography imaging and acoustic emission data acquisition and analysis. The data will reveal how slow and fast deformations develop and interact with each other in dry and wet crustal rocks under the stress, fluid pressure and temperature conditions at depths up to 10 km, and characterize the production of fractures during earthquake nucleation and rupture propagation. We will search for weak signals before dynamic rupture and develop ways to predict the time to failure from these signals. If we can demonstrate that the joint analysis of acoustic emission signals and X-ray microtomography data can be used to predict dynamic rupture in our experiments, we will have discovered an important lead towards earthquake prediction, which we will pursue in follow-up projects. We will compare the deformation microstructures produced in laboratory experiments with those of natural rock samples collected in California and Norway, where earthquakes occurred. The overarching goal is to progress toward a general model of the path to brittle failure in rocks by advancing knowledge of how fractures accumulate before and during both slow and fast earthquakes, under dry conditions and in the presence of water.
Ámbito científico
Programa(s)
Régimen de financiación
ERC-ADG - Advanced GrantInstitución de acogida
0313 Oslo
Noruega