The effects of a tsunami depend on the characteristics of the seismic event that generated the tsunami, the distance from its point of origin, its size (magnitude) and, at last, the configuration of the bathymetry (that is the depth of water in oceans) along the coast that the tsunami is approaching.
http://www.sms-tsunami-warning.com/pages/tsunami-effects
The Division helps communities to prepare for tsunamis by identifying hazard areas (tsunami inundation maps) and areas prone to earthquake-caused ground failure. This information helps planners to select the best evacuation routes and assembly areas.
http://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis
This map shows the epicenter of the Japanese earthquake with the blue area near Sendai showing the rough area affected by the ensuing tsunami. (Zimbio). The tsunami in Japan has affected a wide swath of the northeast coast of the island nation. A massive 8.8 magnitude earthquake with an epicenter near the city of Sendai set off a series of waves that did so far incalculable damage.
http://www.zimbio.com/Japan+Earthquake+2011/articles/Wk-M3vyC2jZ/Tsunami+Japan+2011+Map+Affected+Area
Small islands hit by a tsunami are left unrecognizable. Image: Homes are destroyed by a tsunami. Especially along a high seismic area, known as the Ring of Fire, tsunamis may have dramatic consequences as they hit less developed countries. The buildings infrastructure in these poorer nations are not well built and cannot withstand the impact of the tsunami.
http://www.sms-tsunami-warning.com/pages/tsunami-effects
Volcanic eruptions often have lots of earthquakes, and these can also cause tsunamis, either by moving the ocean floor, or by causing landslides. If the eruption is so large that part of the volcano collapses, then this collapse can also cause a tsunami.
http://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis
However, when tsunami waves become extremely large in height, they savagely attack coastlines, causing devastating property damage and loss of life. A small wave only 30 centimetres high in the deep ocean may grow into a monster wave 30m high as it sweeps over the shore.
http://www.sms-tsunami-warning.com/pages/tsunami-effects
Tsunamis are large and destructive waves caused by earthquakes, landslides, or volcanic eruptions. When a large wave is caused by the resonance of wave energy it is called a 'seiche'. Although they are created differently, both seiches and tsunamis can be large and destructive.
http://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis
The effects of the massive earthquake and tsunami in Japan early this morning are rippling into the west coast of North America, and that means the Twilight cast is high-tailing out of Vancouver, where they have been filming Breaking Dawn. They're evacuating...
http://www.zimbio.com/Japan+Earthquake+2011/articles/Wk-M3vyC2jZ/Tsunami+Japan+2011+Map+Affected+Area
This is an alphabetically sorted list of cities and towns severely damaged by the 2011 Tōhoku earthquake and tsunami. Cities and towns listed here reported at least US$100,000 in damages or at least one death.
https://en.wikipedia.org/wiki/List_of_cities_and_towns_severely_damaged_by_the_2011_T%C5%8Dhoku_earthquake_and_tsunami
Volcanic eruptions can cause also cause tsunamis. Volcanoes near the ocean or a large body of water can cause a tsunami during eruption as pyroclastic flows (a mixture of ash, rock, gas, and water) rapidly flow downhill into the water.
http://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis
what areas are affected by tsunamis
The blue area near Sendai and the rough areas are affected by tsunamis. Epicenter of the Japanese earthquake with the blue area near Sendai showing the rough area affected by the ensuing tsunami.