Coupled modes at interfaces: a review
Wave-to-wave coupling may arise when an acoustic pulse selects a Rayleigh mode of the same speed and both traveltogether swapping energy across an interface. A distinctive coupled signal called Ti was observed at the Hawaii-2 Observatoryfrom earthquakes on the Blanco and Mendocino Fracture Zones, of...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2002 |
| País: | México |
| Institución: | Universidad Nacional Autónoma de México |
| Repositorio: | Redalyc-UNAM |
| OAI Identifier: | oai:redalyc.org:56841201 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=56841201 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias de la Tierra Ware wave coupling nonlinear seismic waves |
| Sumario: | Wave-to-wave coupling may arise when an acoustic pulse selects a Rayleigh mode of the same speed and both traveltogether swapping energy across an interface. A distinctive coupled signal called Ti was observed at the Hawaii-2 Observatoryfrom earthquakes on the Blanco and Mendocino Fracture Zones, off the coast of North America. The signal travels along a purelyoceanic path; it appears to be a composite of undispersed higher Rayleigh modes propagating along the ocean floor both in thesediments and in the water. Coupled modes may be identified by their frequency composition and by their phase and groupvelocities. Seismoacoustic coupling at the seafloor is conditioned on (a) the presence of a low-velocity interface at the ocean floor,(b) the wavelength of the Rayleigh mode being shorter than the depth of the water layer, and (c) weak stress-strain nonlinearity atthe interface. It is conjectured that coupled interface waves may exist at other interfaces, including the Moho and the core-mantleboundary. |
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