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Two‐dimensional simulations of the tsunami dynamo effect using the finite element method
Author(s) -
Minami Takuto,
Toh Hiroaki
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/grl.50823
Subject(s) - dynamo , seafloor spreading , geology , earth's magnetic field , geophysics , dynamo theory , magnetic field , seismology , electromotive force , finite element method , geodesy , physics , quantum mechanics , thermodynamics
Conductive seawater moving in the geomagnetic main field generates electromotive force in the ocean. This effect is well known as the “oceanic dynamo effect.” Recently, it has been reported that tsunamis are also associated with the oceanic dynamo effect, and tsunami‐induced electromagnetic field variations were actually observed on the seafloor. For instance, our research group succeeded in observing tsunami‐induced magnetic variations on the seafloor in the northwest Pacific at the time of the 2011 Tohoku earthquake. In this study, we developed a time domain tsunami dynamo simulation code using the finite element method to explain the tsunami‐induced electromagnetic variations observed on the seafloor. Our simulations successfully reproduced the observed seafloor magnetic variations as large as 3 nT. It was also revealed that an initial rise in the horizontal magnetic component prior to the tsunami arrival as large as 1 nT was induced by the tsunami.