Estimating Oceanic Crustal Structure from OBS Data Using Teleseismic P Wave Wavefield Continuation
Ocean bottom seismometers (OBS) have been widely used in studies of oceanic crustal structure. However, it is challenging to estimate the oceanic crustal structure using teleseismic P waves recorded at a single OBS station, due to water reverberations and the close arrival time between the Moho-converted Ps phase and its multiples. We propose herein a method (the H–β algorithm) based on wavefield continuation and decomposition, whereby the oceanic crustal thickness and average S wave velocity can be estimated by minimizing the energy of the upgoing S wave within the uppermost mantle. Forward tests indicate that the H–β algorithm can resolve the thickness and S-wave velocity of each crustal layer robustly. We apply this method to an OBS station near Hawaii (station PL11) and obtain the oceanic crustal structure beneath the station. The resolved crustal thickness is consistent with previous studies.
KeywordsOcean bottom seismometers wavefield continuation wavefield decomposition oceanic crustal velocity structure
This work made use of the Generic Mapping Tools (GMT) and Seismic Analysis Code (SAC). This study is supported by the National Natural Science Foundation of China (grant nos. 41590854, 41804039, 41774049, 41674051) and Guangdong Province Introduced R&D Team of Geological Processes and Natural Disasters around the South China Sea (2016ZT06N331).
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