EARTHSC 2GG3 Lecture 3: Lecture 3
12 Jan 2017
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Document Summary
They are produced by the sudden displacement of water. Events capable of triggering tsunamis: earthquakes that cause uplift of the seafloor, landslides, volcano flank collapse, submarine volcanic eruptions, meteorites. Earthquakes can cause tsunamis in two ways: by displacement of the seafloor, by triggering a landslide that enters water. Generally, an earthquake must be of at least m7. 5 in order to trigger a tsunami. Tsunamis develop in a 4 stage process. Stage 1. : displacement of the seafloor sets waves in motion that transmit energy outward and upward, when the waves reach the surface of the water, they spread outward. Stage 2. : in the deep ocean, the waves move rapidly (they can reach speeds of over 500 km/h, the spacing of the waves crests if very large (it can be more than. 100 km: the height (amplitude) of the waves is often small (less than 1, passengers on ships in the ocean rarely even notice tsunamis passing beneath them.
