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The Role of Fabric in Frictional Properties of Phyllosilicate-Rich Tectonic Faults
Published on: November 6, 2021
Los cambios de fase del manto y las fallas sísmicas profundas en la litosfera de subducción
Science (New York, N.Y.)
|April 12, 1991
Resumen
Los terremotos profundos, que ocurren a 350-690 km de profundidad, se explican por fallas de transformación. Este proceso implica la inestabilidad del cizallamiento vinculada a las transformaciones de fase en la peridotita rica en olivino dentro de las placas tectónicas de subducción.
Área de la Ciencia:
- La geofísica es la geofísica.
- Sismología Sismología Sismología.
- Física mineral Física de los minerales
Sus antecedentes:
- Las zonas de subducción exhiben zonas sísmicas inclinadas, con una población de profundidad distinta (350-690 km).
- Los mecanismos de falla tradicionales (fractura frágil, deslizamiento por fricción) no se esperan en estas profundidades extremas.
- La comprensión de los terremotos profundos requiere nuevos conceptos geofísicos y geodinámicos.
Objetivo del estudio:
- Explicar la ocurrencia y las características de los terremotos profundos a menos de 350 km.
- Para probar la hipótesis de fallas transformacionales como el mecanismo para los terremotos profundos.
- Para correlacionar la distribución de los terremotos profundos con las transiciones de fase del manto.
Principales métodos:
- Revisión y síntesis de datos experimentales de geofísica sobre las transformaciones de fase mineral.
- Modelado teórico de la inestabilidad del cizallamiento bajo condiciones de estrés no hidrostático.
- Análisis de catálogos de terremotos globales y datos sísmicos para eventos profundos.
Principales resultados:
- El fallo transformacional, una inestabilidad de cizallamiento durante las transformaciones de fase, se identifica como un mecanismo viable.
- Se supone que los terremotos profundos ocurren en cuñas metastables de peridotita ricas en olivino.
- El modelo propuesto se alinea con las distribuciones y características observadas de los terremotos profundos globales y regionales.
Conclusiones:
- Las fallas transformacionales proporcionan una explicación consistente para los terremotos profundos en las zonas de subducción.
- La persistencia de la olivina metastable explica la ocurrencia de terremotos hasta 690 km.
- Los cambios de fase del manto juegan un papel crítico en la generación y los límites de profundidad de los eventos sísmicos profundos.
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