Forces of Nature: Tsunamis

Let's Review: What is a Tsunami? What causes a Tsunami? A tsunami, from the Japanese word for “ harbour wave” is a series of giant, long ocean waves. A tsunami can move hundreds of km per hour in the open ocean and smash into land with waves as high as 30 metres or more. What causes a Tsunami? Tsunamis are created by an underwater tectonic disturbance such as an earthquake, landslide or volcanic eruption.

What Makes Them So Dangerous? Tsunamis can travel up to 700-800 km/hr. At that pace they can cross the entire Pacific Ocean in less than a day. In deep ocean, tsunami waves may appear only a foot high. But as they approach the shoreline and enter shallower water they slow down and begin to grow in energy and height.

Where Do Tsunamis Occur? Most tsunamis, about 80 percent happen within the Pacific Ocean’s “Ring of Fire”. A geologically active area where tectonic shifts make volcanoes and earthquakes common.

Focus On Aceh Province, Indonesia The 2004 Indian Ocean Tsunami was 9.0 quake caused immense damage in many countries. but one of the worst places hit was Banda Aceh in Aceh Province on the island of Sumatra in Indonesia.

Why Was This Area Hit So Hard? High population density & poorly constructed homes Flat, coastal area Very close to the epicentre

Which Tectonic Plates Were Involved?

Banda, Aceh Before...

Banda, Aceh After