Tsunami. slides

Tsunami. slides - Tsunamis What is a tsunami ? A tsunami...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Tsunamis What is a tsunami ? A tsunami is a very long ocean wave generated by sudden displacement of the sea floor or of the oceanic mass The displacement of an equivalent volume of water generates the tsunami Tsunami Terminology The term tsunami is a Japanese word meaning harbour wave It was so named because the wave is harmless until it enters a harbour It is frequently called a tidal wave, but it has nothing to do with tides Structure of a wave Wavelength, , can exceed 200 km normal ocean waves have wavelengths of about 100 m trough; peak; wave height, h ; amplitude From Murck et al. (1996) Velocities in deep water Tsunamis travel very quickly relative to normal ocean waves This is particularly the case in open water, where velocities increase with water depth Velocities can reach 1,000 km/hr in open ocean (normal ocean wave: ~90 km/hr) Thus, velocities are about 10 times higher for tsunamis Shallow water In shallow water, the tsunami waves pile up As a result, velocities and wavelengths decrease... but at the same time, amplitudes can increase enormously... Amplitudes In deep water, wave amplitudes are generally less than 1 meter but in shallow water, amplitudes can reach 40 meters or more above normal sea level Tsunamis take place when a huge earthquake occurs causing the plates below the water to push up causing the water to create a huge wave. In shallow water, the tsunami waves pile up velocities and wavelengths decrease... amplitudes can increase enormously... Hazards and risks of tsunamis Tsunamis can hit with little or no warning 4,000 people have been killed between 1990 and 2000 The most prone areas are those associated with earthquakes and volcanoes (mainly subduction zones) How tsunamis are generated - all involve displacement of water Earthquakes Volcanic activity Submarine landslides Meteorite impacts 1. Earthquakes Mainly vertical crustal movement caused by near-shore or off shore earthquakes so strike-slip faults perhaps less hazardous Magnitude of the earthquake is directly related to the magnitude of the tsunami Tsunami generation 75% of tsunamis are produced in the pacific ocean, most others are in the indian ocean...
View Full Document

This note was uploaded on 03/10/2012 for the course ATOC 181 taught by Professor - during the Fall '06 term at McGill.

Page1 / 62

Tsunami. slides - Tsunamis What is a tsunami ? A tsunami...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online