FAQ Results

Keywords searched: 13 February 2006 Interview with Dr. Hal Mofjeld

1. How do you find out what causes the tsunami? i know valcanos, under water landslides and easthquakes, but how do you know which one starts it ?
2. What gear do you use to study tsunamis?
3. When you tell people to evacuate; how long do you have until the tsunami hits?
4. What if the tsunami warning is too late? Is it possible to stay at your home and survive the tsunami?
5. Where are most tsunami's active and can you get one in one of the Great Lakes?

1. How do you find out what causes the tsunami? i know valcanos, under water landslides and easthquakes, but how do you know which one starts it ?
   
   Actually, it is often very hard to tell about the details of how a tsunami was generated when a volcanic eruption or earthquake also caused an underwater landslide. Surveys by scientists after a tsunami often show evidence of recent landslides near the source. Computer models are then used to estimate how much of the tsunami was generated as the ground moved during the eruption (or earthquake) and how much could have been due to the landslide. This is assuming that the even t did cause the landslide. There are always uncertainties in the conclusions.
   
   Authority: Dr. Hal Mofjeld, interview in February 13, 2006, NOAA Center for Tsunami Research
   
   
2. What gear do you use to study tsunamis?
   
   The equipment and methods used to evaluate a tsunami include bottom imaging (TV and sound-generated) equipment, water depth sounders, bottom samplers, earthquake (seismic) instruments (the data they recorded during an event), land-surveying equipment to survey the flooding by the tsunami, tide gages in harbors (their records of the tsunami) and computers to process the data and run computer models of the tsunami.
   
   Authority: Dr. Hal Mofjeld, interview in February 13, 2006, NOAA Center for Tsunami Research
   
   
3. When you tell people to evacuate; how long do you have until the tsunami hits?
   
   For a dangerous tsunami has been generated far away from an area, the NOAA Tsunami Warning Centers issue a tsunami watch that a dangerous tsunami may be on its way and for people to be alert for further information. A tsunami warning is issued at least 2 hours before the first wave will strike the area. The warning tells people to move to a safe place as quickly as possible.

   When a tsunami is generated nearby, a tsunami warning is issued immediately. For this case, people near the ocean should also u se the natural warning signs such as a strong earthquake, the water level starts changing rapidly, or there is a new loud sound coming from the ocean.
   
   Authority: Dr. Hal Mofjeld, interview in February 13, 2006, NOAA Center for Tsunami Research
   
   

4. What if the tsunami warning is too late? Is it possible to stay at your home and survive the tsunami?
   
   Moving to high ground away from the water before the first tsunami wave strikes is the best approach. If that is not possible, then a well-constructed multi-story building may provide a haven to shelter in place. However, such structures are rare in many coastal areas
   
   Authority: Dr. Hal Mofjeld, interview in February 13, 2006, NOAA Center for Tsunami Research
   
   
5. Where are most tsunami's active and can you get one in one of the Great Lakes?
   
   Most of the recent tsunamis have occurred in the Pacific Ocean and Indonesian Region, but they also occur in the Mediterranean Sea. There is a history of tsunamis in the Great Lakes. These are described at the website of NOAA's National Geophysical Data Center ( http://www.ngdc.noaa.gov/seg/hazard/tsu_db.shtml). If you go to the website and then click on 'EAST COAST of the UNITED STATES and CANADA', it will show you a list of tsunami events that include the Great Lakes.
   
   Authority: Dr. Hal Mofjeld, interview in February 13, 2006, NOAA Center for Tsunami Research