How do scientists gather information and detect tsunamis?
Tsunami scientists gather data from tide gages and do field surveys in areas hit by tsunamis to better understand the behavior of real tsunamis. This information is then used to tune computer models that can be applied to other areas.
I'm assuming you refer to the new DART buoys we're developing. These will help make the tsunami warnings faster and more accurate. Right now, the warning centers depend on earthquake data and on tide gage data to assess the danger. The earthquake data tells you how big the earthquake was, and the location of the epicenter.
If the location is:
- in a region that has generated tsunamis in the past -- basically, very seismically active regions of the "Ring of Fire" around the Pacific Rim, where plate tectonics drives the Pacific plate under various continental plates, and
- if the earthquake is big enough, i.e., about a magnitude 7 or greater, then it is considered a possible tsunami hazard.
But the warning center still doesn't know if a tsunami was generated, because it doesn't have a way to measure it, until the tsunami propagates into a nearby harbor and registers on the tide gage.
That may take a while, and:
- it's too late to warn the folks in that particular harbor and
- you may have lost a lot of time waiting for the tsunami to register on the tide gage.
So DART systems are being place close to the potential tsunamigenic zones, offshore in deep water. That way, if a tsunami is generated by the earthquake, you get the measurement right away. Not only that, but you know that it is headed out to sea and you can warn communities across the ocean that a tsunami is heading toward them.
Authority: Dr. Hal Mofjeld, NOAA Center for Tsunami Research