The USGS says that the February 27 Chile earthquake occurred at the boundary between the Nazca and South American tectonic plates. Also this: "The two plates are converging at a rate of 80 mm per year. The earthquake occurred as thrust-faulting on the interface between the two plates, with the Nazca plate moving down and landward below the South American plate."
The February 27 shock reportedly originated about 230 km north of the source region of the magnitude 9.5 earthquake of May, 1960 – the largest earthquake worldwide in the last 200 years or more.
The 1960 Chilean Tsunami occurred in the aftermath of that 9.5 earthquake in Chile and spawned a tsunami that engulfed the Pacific Ocean.
The 1960 Chilean tsunami radiated outward from
a subduction zone along the coast of Chile.
Its waves reached Hawaii in 15 hours and Japan and the Philippines in 22 hours
Map from USGS
a subduction zone along the coast of Chile.
Its waves reached Hawaii in 15 hours and Japan and the Philippines in 22 hours
Map from USGS
This one from the USGS publication, Surviving a Tsunami—Lessons from Chile, Hawaii, and Japan:
From Chile the tsunami radiated outward, killing 61 people in Hawaii and 122 in Japan. The 1960 Chile earthquake ruptured a fault zone along which a slab of sea floor is descending, or “subducting,” beneath the adjacent South American Continent. Such “subduction zones” are formed where two of the tectonic plates that make up the Earth’s outer shell meet. Earthquakes occur when the fault ruptures, suddenly releasing built-up energy. During the 1960 Chile earthquake, the western margin of the South American Plate lurched as much as 60 feet relative to the subducting Nazca Plate, in an area 600 miles long and more than 100 miles wide.
A Tsunami Advisory is currently in effect ( #12 issued 02/27/2010 at 9:58AM PST) which includes the coastal areas of California, Oregon, Washington, British Columbia and Alaska from the California-Mexico border to Attu, Alaska.
A Tsunami Warning is in effect for the following locations:
CHILE / PERU / ECUADOR / COLOMBIA / ANTARCTICA / PANAMA / COSTA RICA / NICARAGUA / PITCAIRN / HONDURAS / EL SALVADOR / GUATEMALA / FR. POLYNESIA / MEXICO / COOK ISLANDS / KIRIBATI / KERMADEC IS / NIUE / NEW ZEALAND / TONGA / AMERICAN SAMOA / SAMOA / JARVIS IS. / WALLIS-FUTUNA / TOKELAU / FIJI / AUSTRALIA / HAWAII / PALMYRA IS. / TUVALU / VANUATU / HOWLAND-BAKER / NEW CALEDONIA / JOHNSTON IS. / SOLOMON IS. / NAURU / MARSHALL IS. / MIDWAY IS. / KOSRAE / PAPUA NEW GUINEA / POHNPEI / WAKE IS. / CHUUK / RUSSIA / MARCUS IS. / INDONESIA / N. MARIANAS / GUAM / YAP / BELAU / JAPAN / PHILIPPINES / CHINESE TAIPEI
The USGS publication, Surviving a Tsunami—Lessons from Chile, Hawaii, and Japan also include eyewitness accounts on surviving the tsunami:
Actions that saved lives, and actions that cost lives, as recounted by eyewitnesses to the tsunami from the largest earthquake ever measured—the magnitude 9.5 earthquake in Chile on May 22, 1960. In interviews several decades later, people in Chile, Hawaii, and Japan recall the tsunami
Their accounts contain lessons on tsunami survival:
- Many Will Survive the Earthquake
- Heed Natural Warnings
- Heed Official Warnings
- Expect Many Waves
- Head for High Ground and Stay There
- Abandon Belongings
- Don’t Count on the Roads
- Go to an Upper Floor or Roof of a Building
- Climb a Tree
- Climb onto Something that Floats
- Expect the Waves to Leave Debris
- Expect Quakes to Lower Coastal Land
- Expect Company
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