EOSC 114 Lecture Notes - Lecture 25: Subduction, Krakatoa, Pressure Sensor
22 Mar 2018
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Document Summary
The narrowed topography of a harbour focuses the wave into a smaller space: very dangerous. Rapid displacement of large amounts of ocean water. For examples: a tsunami can be produced by sudden vertical changes in seafloor. The energy released by a seismic vertical movments: Ice bergs (falling from glaciers, usually the smallest) Landslides: flows away radially from the point source, propagates as a wave train across the ocean, disturbs the entire water column. Steepness <<< 1 (almost flat) (cid:862)(cid:449)a(cid:448)e trai(cid:374)(cid:863): a short (cid:271)urst of lo(cid:272)alized (cid:449)a(cid:448)e a(cid:272)tio(cid:374) that tra(cid:448)els as a u(cid:374)it. Wave height ~0. 5 1 m (very small) Which is true? b deep water waves do not feel the bottom, shallow water waves feel the bottom. Wavelength = 100,000 200,000 m. Remember, speed of shallow water wave is celerity = 3. 1 sqrtd, where d = ocean depth. All tsunami waves cross a given part of the ocean at the same speed (speed only depends upon water depth)
