GEOG 001 Lecture Notes - Lecture 23: Flor, Halifax Explosion, Subduction
19 Aug 2020
School
Department
Course
Professor
Document Summary
An earthquake can cause a tsunami by displacing the seafloor or the floor of a large lake, or by triggering a landslide. Displacement of seafloor is the most common, occurs when a block of. Earth"s crust moves rapidly up or down during an earthquake. Generally takes an earthquake with a magnitude of 7. 5+ to generate a damaging tsunami. The upward or downward movement of the seafloor displaces the overlying water and initiates a four-stage process that culminates with the tsunami rushing ashore. Displacement of the seafloor during an earthquake sets in motions oscillatory waves that transmit energy outward and upward from the source. These waves intercept the ocean surface and spread outward. In the deep ocean, the waves move more rapidly and are spaced far apart. Their velocity is equal to the square root of the product of the acceleration of gravity and water depth. In deep ocean the spacing between crests of waves may be more than.
