Tsunami: the Great Waves
Presented by
U.S. Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
Intergovernmerntal Oceanographic Commission
International Tsunami Information Center
The purpose of this brochure is to increase awareness and knowledge of tsunamis. Please share what you learn; knowing the right information may save your life and the lives of those you love.
The phenomenon we call "tsunami" (soo-NAH-mee) is a series of traveling ocean waves of extremely long length generated by disturbances associated primarily with earthquakes occurring below or near the ocean floor. Underwater volcanic eruptions and landslides can also generate tsunamis. In the deep ocean, their length from wave crest to wave crest may be a hundred miles or more but with a wave height of only a few feet or less. They cannot be felt aboard ships nor can they be seen from the air in the open ocean. In deep water, the waves may reach speeds exceeding 500 miles per hour.
Tsunamis
are a threat to life and property to anyone living near the ocean. For
example, in 1992 and 1993 over 2,000 people were killed by tsunamis
occurring in Nicaragua, Indonesia and Japan. Property damage was nearly
one billion dollars. The 1960 Chile Earthquake generated a Pacific-wide
tsunami that caused widespread death and destruction in Chile, Hawaii,
Japan and other areas in the Pacific. Large tsunamis have been known
to rise over 100 feet, while tsunamis 10 to 20 feet high can be very
destructive and cause many deaths and injuries.
The Tsunami Warning System (TWS) in the Pacific, comprised of 26 participating international Member States, monitors seismological and tidal stations throughout the Pacific Basin. The System evaluates potentially tsunamigenic earthquakes and disseminates tsunami warning information. The Pacific Tsunami Warning Center (PTWC) is the operational center of the Pacific TWS. Located in Honolulu, Hawaii, PTWC provides tsunami warning information to national authorities in the Pacific Basin.
Learn more about Tsunamis:
Warnings Dissemination and Research Activities
ACKNOWLEDGMENTS THE PREPARATION OF THIS BROCHURE WAS SUPPORTED BY:
DEPARTMENT OF COMMERCE, NATIONAL OCEANIC AND ATMOSPHERIC
ADMINISTRATION, NATIONAL WEATHER SERVICE
UNESCO, INTERGOVERNMENTAL OCEANOGRAPHIC COMMISSION,
INTERNATIONAL TSUNAMI INFORMATION CENTER
TECHNICAL GUIDANCE PROVIDED BY:
INTERNATIONAL TSUNAMI INFORMATION
CENTER
NATIONAL WEATHER SERVICE
NATIONAL OCEAN SERVICE
NATIONAL GEOPHYSICAL DATA CENTER
PACIFIC MARINE ENVIRONMENTAL LABORATORY
HYDROGRAPHIC AND OCEANOGRAPHIC OFFICE, CHILE
SCHOOL OF OCEAN & EARTH SCIENCE & TECHNOLOGY, UNIVERSITY OF
HAWAII
Office of Climate, Weather, and Water Services
National Weather Service
1325 East-West Hwy
Silver Spring, MD
20910-3283
Questions or comments: melody.magnus@noaa.gov