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Anisotropía en el núcleo interno: ¿Podría ser debido a la convección de bajo orden?
Romanowicz1, Li, Durek
1B. Romanowicz, Seismographic Station and Department of Geology and Geophysics, University of California at Berkeley, Berkeley, CA 94720, USA. X.-D. Li and J. Durek, Seismographic Station, University of California at Berkeley, Berkeley, CA 94720, USA.
Science (New York, N.Y.)
|November 8, 1996
Resumen
Nuevos datos sobre el núcleo interno de la Tierra revelan patrones de anisotropía sísmica inconsistentes con las estructuras congeladas. Los hallazgos sugieren que la convección a gran escala es el principal impulsor de las distribuciones de velocidad de las ondas P observadas.
Área de la Ciencia:
- La geofísica es la geofísica.
- Sismología Sismología Sismología.
- Ciencias de la Tierra Ciencias de la Tierra Ciencias de la Tierra
Sus antecedentes:
- El núcleo interno de la Tierra exhibe complejas propiedades sísmicas, incluida la anisotropía.
- Comprender la anisotropía del núcleo interno es crucial para descifrar sus procesos dinámicos.
Objetivo del estudio:
- Para restringir los patrones de anisotropía en el núcleo interno de la Tierra.
- Para investigar los mecanismos físicos responsables de la anisotropía sísmica observada.
Principales métodos:
- Utilizó un conjunto de datos recientemente reunido de mediciones de división de oscilación libre sensibles al núcleo interno.
- Tiempos de viaje del diferencial de onda corporal incorporado.
- Aplicó un formalismo que permite desviaciones de la simetría radial y la anisotropía cilíndrica.
Principales resultados:
- Desarrolló modelos de distribuciones de velocidad de ondas P dentro del núcleo interno.
- Se descubrió que la fuerza y el patrón de la velocidad de la onda P eran incompatibles con la anisotropía congelada.
- La evidencia sugiere fuertemente un simple régimen de convección a gran escala.
Conclusiones:
- La anisotropía sísmica observada en el núcleo interno es probablemente el resultado de procesos dinámicos, no de estructuras estáticas.
- La convección a gran escala es el mecanismo dominante que da forma a los patrones de velocidad de onda P del núcleo interno.
- Este estudio proporciona nuevos conocimientos sobre la evolución en curso del interior profundo de la Tierra.
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