Are all the tsunamis over coasts caused by tsunami japan?

Not at all. Tsunamis can occur anywhere along the coast where the sea floor abruptly changes, causing a seismic disturbance. Although the 2011 Tōhoku earthquake and tsunami in Japan was a powerful and destructive event, tsunamis can be triggered by various factors, including underwater earthquakes, landslides, volcanic eruptions, and even asteroid impacts.

Here are some examples of tsunamis that were not caused by the tsunami in Japan:

1. 2004 Indian Ocean Tsunami: This devastating event was triggered by a massive undersea earthquake with a magnitude of 9.1 off the coast of Indonesia. The resulting tsunamis caused widespread destruction and loss of life across several countries in the Indian Ocean region.

2. 2018 Alaska Tsunami: A 7.9 magnitude earthquake near the Gulf of Alaska generated a tsunami that caused damage along the coastline of the US state of Alaska.

3. 1960 Chilean Tsunami: This major tsunami was caused by a powerful 9.5 magnitude earthquake in southern Chile. The tsunamis reached as far as Japan, Hawaii, and the Philippines.

4. 1883 Krakatoa Eruption: The eruption of Krakatoa, a volcanic island in Indonesia, triggered a series of tsunamis in the Sunda Strait, causing significant destruction and loss of life.

5. 1755 Lisbon Earthquake and Tsunami: A massive earthquake with an estimated magnitude of 8.5 struck off the coast of Portugal, generating tsunamis that devastated coastal areas in Portugal and throughout the Atlantic Ocean.

These are just a few examples of tsunamis that occurred due to factors unrelated to the tsunami in Japan. Tsunamis can be caused by natural events that disrupt the balance of the ocean, and their impact can vary depending on the magnitude of the triggering event and the local geography.