Speaker
Description
Fault rupture in a subduction zone often causes devastating earthquake and tsunami hazards. Therefore, understanding a slip behavior along the fault is a crucial scientific topic and a deeply socially relevant problem. To understand the slip behavior along the fault, there are two kinds of essential geophysical datasets. One is seafloor displacement as a surface response of a fault slip, and the other is the sub-seafloor structure, which is needed to transform a surface displacement to a fault displacement. Recent studies reveal that surface displacements due to fault slips show a wide-spectrum of their frequency, from a regular earthquake (~10 Hz) to a long-term slow slip (~months). To monitor the entire spectrum of the fault slip, monitoring the displacement with a seismo-geodetic band in real-time continuously is necessary. And also, to transform the displacement to the slip along the fault, it is essential to know a realistic structure of a medium (lithospheric structure) in the subduction zone. JAMSTEC is conducting an integrated geophysical project to establish a real-time continuous seafloor geodetic network in the Nankai Trough, Japan, and construct a three-dimensional structural model using seismic data. We will present an outline and recent results of the project in this presentation.
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The sensing and modeling the seafloor displacement can be utilize other kind of monitoring of signal propagating through the earth and/or the ocean, such as signals from Nuclear-Test-Ban