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Evidencia sísmica de los límites agudos entre la litosfera y la astenosfera de las placas oceánicas
Hitoshi Kawakatsu1, Prakash Kumar, Yasuko Takei
1Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan. hitosi@eri.u-tokyo.ac.jp
Science (New York, N.Y.)
|April 25, 2009
Resumen
La tectónica de placas se basa en el movimiento de la litosfera sobre la astenosfera. La comprensión del límite litosfera-astenosfera (LAB) revela estructuras agudas y dependientes de la edad con capas ricas en fusión que facilitan el movimiento de las placas.
Área de la Ciencia:
- La geofísica es la geofísica.
- La tectónica es la tectónica.
- Sismología Sismología Sismología.
Sus antecedentes:
- La tectónica de placas describe el movimiento de la litosfera sobre la astenosfera.
- El límite entre la litosfera y la astenosfera (LAB) es crucial para comprender la dinámica de la Tierra.
- Las placas oceánicas ofrecen modelos más simples para estudiar el LAB.
Objetivo del estudio:
- Para investigar las características del LAB debajo de las placas oceánicas.
- Comprender el estado físico de la astenosfera y su papel en la tectónica de placas.
Principales métodos:
- Análisis de los datos sísmicos de los sismómetros de fondo oceánico de banda ancha de pozo de perforación.
- Interpretación de las reducciones de la velocidad de la onda de corte.
Principales resultados:
- El LAB debajo de las placas del Pacífico y del Mar de Filipinas es agudo y dependiente de la edad.
- Se observó una reducción significativa en la velocidad de la onda de cizallamiento en el LAB.
- La evidencia sugiere una astenosfera parcialmente fundida con capas horizontales ricas en fusión.
Conclusiones:
- La astenosfera contiene capas ricas en fundido que crean un gran contraste de viscosidad en el LAB.
- Este contraste de viscosidad facilita los movimientos horizontales de las placas, un aspecto clave de la tectónica de placas.
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