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Núcleo de terremoto por deformaciones transitorias causadas por el M = 7.9 Denali, Alaska, terremoto
1US Geological Survey, Center for Earthquake Research and Information, 3876 Central Ave. Suite 2, The University of Memphis, 3876 Central Ave. Suite 1, Memphis, Tennessee 38152-3050, USA. gomberg@usgs.gov
Nature
|February 13, 2004
Resumen
El terremoto de Denali de 2002 desencadenó actividad sísmica en todo el oeste de América del Norte, incluso en áreas con bajo estrés tectónico. Esto sugiere que el desencadenamiento dinámico es generalizado e impredecible, ocurriendo en fallas de estrés crítico.
Área de la Ciencia:
- La geofísica es la geofísica.
- Sismología Sismología Sismología.
- La tectónica es la tectónica.
Sus antecedentes:
- Los terremotos son provocados por cambios de estrés, pero la magnitud de estos cambios es mucho menor que el estrés liberado por el propio terremoto.
- Esto implica que el desencadenamiento ocurre en fallas que ya están críticamente estresadas.
- Las presiones elevadas de los poros, potencialmente de los fluidos de alta temperatura, pueden reducir las tensiones de fricción y promover la falla.
Objetivo del estudio:
- Para investigar la sismicidad generalizada provocada por el terremoto de 2002 en Denali, Alaska.
- Para determinar si el desencadenamiento dinámico por ondas sísmicas se ve reforzado por la directividad de ruptura.
- Para comparar la escala de activación causada por el terremoto de Denali con eventos anteriores, como el terremoto de Landers de 1992.
Principales métodos:
- Análisis de registros sísmicos y de muestras altas de GPS del terremoto de 2002 en Denali.
- Comparación de los patrones de sismicidad desencadenados con la directividad de ruptura del terremoto.
- Comparación de la extensión de la sismicidad desencadenada con la del terremoto de Landers de 1992.
Principales resultados:
- El terremoto de Denali de 2002 desencadenó un aumento generalizado de la sismicidad en toda la Columbia Británica y el oeste de los Estados Unidos.
- Se verificó la directividad de la ruptura para mejorar el desencadenamiento dinámico en direcciones específicas.
- La escala de la sismicidad desencadenada fue comparable a la del terremoto de Landers de 1992.
Conclusiones:
- El desencadenamiento dinámico por terremotos grandes puede ocurrir a grandes distancias y en áreas no obviamente tectónicamente activas.
- Las fallas pueden tener un estrés crítico incluso en regiones con bajas tasas de estrés ambiental.
- La activación dinámica parece ser un fenómeno ubicuo e impredecible en la sismología.
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