New Information on Tsunami Earthquakes

35 years ago tsunami earthquakes were a strange mystery scientists found quite baffling. Unlike a usual earthquake, which generates violent shaking and can be easily recognized in time to evacuate, the tsunami earthquake is something much more insidious.

Tsunami earthquakes are very slow and relatively mild, but somehow they can cause the huge waves that can devastate coastal cities. After years of research, a team of scientists believe they may have tracked down the root cause.

It is now believed by some scientists that these type of earthquakes occur when two tectonic plates get hung up on an extinct volcano–or seamount–on the ocean’s floor. These seamounts can sometimes get squashed as one tectonic plate slides under the other one, causing the slow tremors they sought to explain.

The earthquake that happened on July 3 off the coast of New Zealand does not appear to have been the kind of event described above. The quake was a 6.3 near the Kermadec Islands Region. It occurred at a depth of 20.5 miles and was 145 miles southeast of Raoul Island. It happened not two weeks after another quake in the same area that had a magnitude of 7.2.

However, that particular earthquake had a cousin off the coast of Alaska that shook at a 7.9 near the Aleutian Islands. But even though a localized tsunami wave hit there, it did not reach the heights of the 40 foot waves a tsunami earthquake usually causes. Further details of that quake and tsunami were discussed in the Inquisitr in this article.

The good news is, tsunami styled earthquakes seem to be quite rare. It’s taken 35 years to study them because they occur so rarely, and the team of researchers had to study numbers from data collected for other reasons, as well as talk to eye witnesses, to reach their conclusions.


NOAA, or National Oceanic and Atmospheric Administration, works tirelessly to monitor all oceanic and weather activities which might pose a threat to people in a certain area. It’s this organization who issues the public warnings to evacuate, so if you’re at all concerned about waves or weather smashing your home, this is the link for you.

It’s good to know a tsunami is on the way, of course, but once you’re aware of that danger, here is a video that will tell you what to do about it.

[image from REUTERS/YOMIURI]