Tsunamis’ Magnetic Fields are Detectable Before Sea Level Change
upstart writes:
Tsunamis generate magnetic fields as they move conductive seawater through the Earth's magnetic field. Researchers previously predicted that the tsunami's magnetic field would arrive before a change in sea level, but they lacked simultaneous measurements of magnetics and sea level that are necessary to demonstrate the phenomenon.
The new study provides real-world evidence for using tsunamis' magnetic fields to predict the height of tsunami waves using data from two real events -- a 2009 tsunami in Samoa and a 2010 tsunami in Chile -- that have both sets of necessary data. The new study was published in AGU's Journal of Geophysical Research: Solid Earth, which focuses on the physics and chemistry of the solid Earth.
The study confirms the magnetic field generated by a tsunami arrives ahead of sea-level change and that its magnitude can be used to estimate the tsunami's wave height. How much earlier the magnetic field arrives depends on water depth, but in their results, the study authors found the early arrival time to be about one minute prior to sea level change over a 4,800-meter deep sea.
Journal Reference:
Zhiheng Lin, Hiroaki Toh, Takuto Minami. Direct Comparison of the TsunamiGenerated Magnetic Field With Sea Level Change for the 2009 Samoa and 2010 Chile Tsunamis, Journal of Geophysical Research: Solid Earth (DOI: 10.1029/2021JB022760)
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