tsunamis Flashcards
1
Q
what is a tsunami?
A
series of waves caused by the displacement of large quantities of water- water column displacement. this is caused by submarine earthquakes, landslides or volcanic eruptions.
2
Q
how are tsunamis formed?
A
- plate shifts abruptly causing earthquake and displacing water/ material from eruption or landslide falls into sea displacing water.
- waves are generated and move out in all directions across the ocean (some as fast as 600km)
- as tsunami wave reaches shallower water friction between wave and seabed increases, the tsunami wave slows down and compresses- decreasing wavelength but increasing wave height.
- wave height continues to increase and currents intensify becoming threat and a danger as it approaches the shore.
3
Q
affecting factors
A
- duration of event: longer = more damage
- wave amplitude
- coastline geography: shallow/coastal plains/ river valleys
- coastline ecosystem
- time of day/quality of early warning
- degree of coastal development and its prox. to the coast