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Las tasas de deslizamiento de fallas en la moderna zona sísmica de Nueva Madrid
1Department of Geological Sciences, University of Colorado, Boulder, CO 80309-0399, USA. Department of Geology, University of Arkansas, Fayetteville, AR 72701, USA. William Lettis and Associates, 1777 Botelho Drive, Suite 262, Walnut Creek, CA 945.
Science (New York, N.Y.)
|November 5, 1999
Resumen
Los sedimentos del Holoceno tardío revelan plegamientos relacionados con fallas por encima de la falla de empuje Reelfoot en la zona sísmica de Nuevo Madrid. Este estudio cuantifica las tasas de deslizamiento, cruciales para comprender los peligros sísmicos en la región.
Área de la Ciencia:
- Geología Geología Geología.
- Sismología Sismología Sismología.
- La geofísica es la geofísica.
Sus antecedentes:
- La zona sísmica de Nueva Madrid es una región de riesgo sísmico significativo en el centro de los Estados Unidos.
- Comprender la actividad de las fallas ciegas es crucial para la evaluación del riesgo sísmico.
Objetivo del estudio:
- Para analizar los sedimentos del Holoceno tardío en la región del condado de Lake para comprender la deformación por encima de la falla de empuje Reelfoot.
- Para cuantificar la tasa de deslizamiento de la falla de empuje Reelfoot y la zona sísmica de Nueva Madrid.
Principales métodos:
- Análisis estructural y geomórfico de sedimentos del Holoceno tardío.
- Modelado de la escarpa Reelfoot como un miembro delantero en un pliegue de curvatura de falla utilizando anchos de banda kink de exposiciones de trincheras.
- Cálculo de las tasas de deslizamiento utilizando alivio estructural y caída de falla estimada.
Principales resultados:
- Los sedimentos se deforman por plegamientos relacionados con fallas por encima de la falla ciega de empuje Reelfoot.
- La tasa de deslizamiento en el empuje ciego se estima en 6,1 +/- 0,7 mm / año durante los últimos 2300 +/- 100 años.
- El cálculo de la tasa de deslizamiento alternativo para el empuje ciego dio 4.8 +/- 0.2 mm / año.
- La tasa estimada de deslizamiento lateral derecho para la zona sísmica de Nueva Madrid es de 1,8 a 2,0 mm/año.
Conclusiones:
- La falla de empuje Reelfoot está activa y contribuye a la deformación en la zona sísmica de Nuevo Madrid.
- Los datos de la tasa de deslizamiento proporcionan información crítica sobre el potencial sísmico de la región.
- Las relaciones geométricas sugieren una contribución específica del deslizamiento lateral derecho a la actividad general de la zona sísmica.
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