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| | Abstract | | For imaging deep crustal structures using reflections in waveform records of local earthquakes, we propose a reverse-time passive seismic imaging technique. The proposed method, which is based on reverse time migration (RTM), correlates the forward and backward extrapolated wavefields from seismic stations using recorded waveforms without any source information. In this study, we conducted a numerical simulation study with a 400 km x 64 km two-dimensional model of the plate subduction zone in SW Japan. We compared RTM results from acoustic and elastic synthetics with an ideal dense observation or an actual sparse observation. We demonstrated the effective P-wave reflection imaging both in the acoustic and elastic cases. However, degrading of the image quality was also observed due to S-wave contamination and the sparseness of seismic stations. Our results suggest further challenges for application to actual earthquake records with seismograph network, such as data preconditioning, post-processing of RTM images, and implementation of imaging conditions with potential representation. |
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