Tsunamis are incorrectlynamed tidal waves. Tidal waves are caused by extremely strong winds andtsunamis are caused by other things. Tsunami means “harbor wave” in JapaneseTsunamis are one of the deadliest natural disasters. They can wipe outlarge numbers of people. An earthquake is one of the causes of tsunamis.
Soare undersea landslides, volcanic eruptions, and rarley meteorites andasteroids. The earthquakes that cause tsunamis are submarine earthquakes. That meansthat they happen under water. An earthquake must rate above a 7.
5 on theRichter Scale to cause a tsunami. The ground shoots up and displaces thewater. This causes the tsunami wave to form and move. As the waveapproaches land, it increases in size. When it reaches the land, it washesover anything in its path.
They are so strong they can knock down buildingsand trees. Tsunamis can do a lot things. They cause floods, destruction, and deaths. Tsunamis may also bring diseases like cholera.
This can happen when deadbodies that have not been buried decay. Many times more people die from thediseases than the actual tsunami. The deadliest tsunami occurred on December 26, 2004 and killed 150,000people. It affected the countries of South East Asia. They are as follows:Indonesia, India, Bangladesh, Thailand, Sri Lanka, Malaysia, Kenya,Sumatura, Maldives, Myanyar, and Somalia. Tsunamis (pronounced tsoo-nah’-mee), or seismic sea waves, potentially the most catastrophic of all ocean waves, are generated by tectonic displacement–for example, volcanism, landslides, or earthquakes–of the seafloor, which in turn cause a sudden displacement of the water above and the formation of a small group of water waves having wavelength equal to the water depth (up to several thousand meters) at the point of origin.
These waves can travel radially outward for thousands of kilometers while retaining substantial energy. Their speed–characteristic of gravity waves in shallow water and thus equal to the square root of gD, where g is the gravitational constant and D is the depth–is generally about 500 km/h (300 mph), and their periods range from 5 to 60 minutes. In the open ocean their amplitude is usually less than 1 m (3. 3 ft); thus tsunamis often go unnoticed by ships at sea. In very shallow water, however, they undergo the same type of increase in amplitude as swell approaching a beach.
The resultant waves can be devastating to low-lying coastal areas; the 37-m (120-ft. ) waves from the 1883 Krakatoa eruption, for example, killed 36,000 people. The characteristics of tsunamis as they approach shore are greatly affected by wave refraction over the local bathymetry. Tsunami-producing earthquakes usually exceed 6.
5 on the Richter scale, and most tsunamis occur in the Pacific Ocean because of the seismic activity around its perimeter. A tsunami warning system for the Pacific Ocean has been established; it consists of strategically placed seismic stations and a communications network. If within an evacuation zone, take the following actions: picLOCAL EARTHQUAKE – May cause you to fall or have difficulty standing. This is a natural tsunami warning.
Initially, protect yourself from earthquake effects. When the shaking stops, leave the evacuation zones immediately. picURGENT TSUNAMI WARNING – Possible tsunami generated by a significant earthquake in local waters. Sirens will sound.
Turn on radio. If an urgent tsunami warning for Oahu is announced, leave the evacuation zones immediately. picTSUNAMI WATCH – Significant distant earthquake has occurred. Tsunami approach not confirmed but possible. No siren sounding.
Prepare for possible upgrade to tsunami warning. picTSUNAMI WARNING – Tsunami approach confirmed. Sirens will sound. Monitor radio.
Be prepared to evacuate when advised/ordered by civil defense. picTSUNAMI EVACUATION – Sirens will sound. Turn on radio. Those who are in tsunami evacuation zones must begin evacuation when the evacuation advisory/order is issued by civil defense (3 to 4 hours prior to wave arrival). City busses will leave evacuation zones, and roads will be sealed off by police no later than 45 minutes prior to first wave arrival.
picIf you are in a steel and/or concrete building of six or more stories move to the third floor or above and remain there until the “All Clear” is announced. .