A tsunami is a long-wavelength, gravity-driven water wave phenomenon typically generated by large, sudden displacements of the seafloor due to subduction-zone earthquakes, but also by submarine landslides, volcanic eruptions, or impact events. In deep ocean, tsunamis travel at jetliner speeds with low amplitudes and very long periods (minutes to an hour), behaving as shallow-water waves whose phase speed depends on water depth. As they shoal on continental shelves, energy conservation forces rapid increases in wave amplitude and reductions in wavelength and speed, producing highly nonlinear run-up, strong nearshore currents, and complex inundation patterns that are central to hazard assessment and numerical modeling.
Tsunamis pose a risk to the entire California coast. But should a major one strike, how bad could it be?
Earth Sciences
Jun 9, 2025
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In September 2023, a bizarre global seismic signal was observed which appeared every 90 seconds over nine days—and was then repeated a month later. Almost a year later, two scientific studies proposed that the cause of these ...
Earth Sciences
Jun 3, 2025
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Analysis has shown a boulder weighing almost 1,200 tons in Tonga is one of the largest known wave-transported rocks in the world, providing new insights into the Pacific region's history and risk of tsunamis.
Earth Sciences
May 21, 2025
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Amber deposits found in ancient deep-sea sediment may represent one of the oldest records to date of a tsunami, suggests research published in Scientific Reports. The study describes large amber deposits discovered on Hokkaido ...
Earth Sciences
May 15, 2025
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A 6.6-magnitude earthquake struck far off southwest Australia on Wednesday, but no tsunami warning was issued.
Environment
Apr 16, 2025
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The risk of damaging flooding from a major tsunami may be greater than many realized along stretches of California's renowned coastline, state officials say, further reinforcing the need for residents to take note if they ...
Earth Sciences
Mar 19, 2025
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The international Surface Water and Ocean Topography (SWOT) satellite mission, a collaboration between NASA and France's CNES (Center National d'Études Spatiales), detected the unique contours of a tsunami that sloshed within ...
Planetary Sciences
Nov 1, 2024
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