2004 Earthquake And Tsunami
Charise Zelnick
Although earthquake magnitude is one factor that affects tsunami generation, there are other important factors to consider. The earthquake must be a shallow marine event that displaces the seafloor. Thrust earthquakes (as opposed to strike slip) are far more likely to generate tsunamis, but small tsunamis have occurred in a few cases from large (i.e., > M8) strike-slip earthquakes.
Earthquakes of this size do not usually produce destructive tsunamis. However, small sea level changes might be observed in the vicinity of the epicenter. Tsunamis capable of producing damage or casualties are rare in this magnitude range but have occurred due to secondary effects such as landslides or submarine slumps.
Earthquakes of this size might produce destructive tsunamis, especially near the epicenter. At greater distances, small sea level changes might be observed. Tsunamis capable of producing damage at great distances are rare in the magnitude range.
Destructive local tsunamis are possible near the epicenter, and significant sea level changes and damage might occur in a broader region. Note that with a magnitude 9.0 earthquake, there is a possibility of an aftershock of magnitude 7.5 or greater.
Large tsunamis have occurred in the United States and will undoubtedly occur again. Significant earthquakes around the Pacific rim have generated tsunamis that struck Hawaii, Alaska, and the U.S. west coast. One of the largest and most devastating tsunamis that Hawaii has experienced was in 1946 from an earthquake along the Aleutian subduction zone. Runup heights reached a maximum of 33 to 55 feet...
NOAA (National Oceanic and Atmospheric Administration) maintains the U.S. Tsunami Warning Centers , and work in conjunction with USGS seismic networks to help determine when and where to issue tsunami warnings. Also, if an earthquake meets certain criteria for potentially generating a tsunami, the pop-up window and the event page for that earthquake on the USGS Latest Earthquakes Map will include...
Tsunamis are ocean waves triggered by: Large earthquakes that occur near or under the ocean Volcanic eruptions Submarine landslides Onshore landslides in which large volumes of debris fall into the water Scientists do not use the term "tidal wave" because these waves are not caused by tides. Tsunami waves are unlike typical ocean waves generated by wind and storms, and most tsunamis do not "break"...
Although both are sea waves, a tsunami and a tidal wave are two different and unrelated phenomena. A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth ("tidal wave" was used in earlier times to describe what we now call a tsunami.) A tsunami is an ocean wave triggered by large earthquakes that occur near or under the ocean, volcanic...
- Not all tsunamis are generated by earthquakes.
- Tsunamis can be caused by volcanoes, landslides, and even atmospheric disturbances
- Data from tide gauges can help unravel the complex physics of these sources
Tsunamis are devastating. Usually associated with earthquakes in the Pacific, these giant surges of oceanic water can kill thousands and do billions of dollars of damage in minutes. Surprisingly, most people in Oregon are not aware of the tsunami history and hazard along our very own coast.
Tsunami Preparedness explains how and why tsunamis occur, how to know that a tsunami is approaching, and what you should do. These issues are addressed by scientists, emergency managers, and first responders.
Tsunamis are a constant threat to the coasts of our world. Although tsunamis are infrequent along the California coast, it is possible and necessary to prepare for potential tsunami hazards to minimize loss of life and property. Community awareness programs are important, as they strive to create an informed society by providing education and training.
A severely damaged home, or a portion of one, sits atop debris in Banda Aceh on the island of Sumatra. Damage was caused by a massive, highly destructive tsunami, triggered by a magnitude 9.1 earthquake just offshore of Sumatra, on December 26, 2004.
Executive SummaryPuerto Rico and the Virgin Islands are located at an active plate boundary between the North American plate and the northeast corner of the Caribbean plate. The region was subject in historical times to large magnitude earthquakes and devastating tsunamis. A major downward tilt of the sea floor north of Puerto Rico and the Virgin Islands, large submarine rockslides, and an unusual
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