Theoretical modeling and numerical simulation of seismic motions at seafloor
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This paper proposes a modelling and simulation method of seafloor seismic motions on offshore sites, which are composed of the base rock, the porous soil layers and the seawater layer, based on the fundamental hydrodynamics equations and one-dimensional wave propagation theory. The base rock motions are assumed to consist of P- and S-waves and are modelled by the seismological model in southwest of Western Australia (SWWA). The transfer functions of the offshore site are calculated by incorporating the derived dynamic-stiffness matrix of seawater layer into the total stiffness matrix. The effect of water saturation on the P-wave velocity and Poisson’s ratio of subsea soil layers are also considered in the model. Both onshore and seafloor seismic motions are stochastically simulated. The comparison results show that the seafloor vertical motions are significantly suppressed near the P-wave resonant frequencies of the upper seawater layer, which makes their intensities much lower than the onshore vertical motions. Owing to their compliance with the characteristics of available seafloor earthquake recordings, the proposed method can be used to simulate seafloor motions for offshore structural seismic analyses.
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Li, C.; Li, H.; Bi, Kaiming; Hao, H. (2017)This paper proposes a simulation method of three-component seafloor seismic motions using onshore earthquake recordings. Firstly, a pair of onshore and seafloor motions recorded during one earthquake is selected; the ...
Hao, Hong; Bi, Kaiming; Li, C.; Li, H. (2017)© 2017 Taylor & Francis Group, London. Seismic motions at seafloor are different from those at onshore sites since seawater can significantly suppress the seafloor vertical motions at the P-wave resonant frequencies of ...
Li, C.; Li, H.; Hao, Hong; Bi, Kaiming (2018)Compared to the seismic motions recorded on the onshore sites, the quantity of offshore earthquake recordings is very limited. This paper presents a novel method to simulate spatially varying ground motions at multiple ...