March 8th, 2010
The magnitude 8.8 quake that slammed central Chile February 27 knocked the entire planet for a loop — literally. The sudden, large-scale movement of tectonic plates that triggered the quake shifted immense masses of rock a few meters closer to Earth’s core, tilting the planet’s axis a few centimeters and imperceptibly shortening the day.
Credit: US Geological Survey.
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March 8th, 2010
Born 175 years ago this week, Italian astronomer Giovanni Schiapparelli became famous for his telescopic observations of Mars in 1877. He discerned numerous linear surface patterns that he called “canali,” a word that means “channels” in Italian but was widely mistranslated as “canals.”
Canals are artificial structures, and that is just what American astronomer Percival Lowell (born 155 years ago this week) believed he saw the more he observed and mapped Mars. He popularized a belief in the “Canals of Mars” and their presumed builders that would last for nearly a century.
Image credit: NASA / JPL / University of Arizona
This Mars Reconnaissance Orbiter image provides strong evidence that these gullies on a crater rim were formed by fluid flow of a natural sort, hinting that Mars indeed once had water flowing on its surface.
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March 5th, 2010
When compared to brown bears, polar bears are the new species on the block. The two species diverged from each other 150,000 years ago on islands in the Alexandar Archipelago, Southeast Alaska.
Photo courtesy US FWS.
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February 27th, 2010
Tectonic Summary
This earthquake occurred at the boundary between the Nazca and South American tectonic plates. 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.
Coastal Chile has a history of very large earthquakes. Since 1973, there have been 13 events of magnitude 7.0 or greater. The February 27 shock 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. This giant earthquake spawned a tsunami that engulfed the Pacific Ocean. An estimated 1600 lives were lost to the 1960 earthquake and tsunami in Chile, and the 1960 tsunami took another 200 lives among Japan, Hawaii, and the Philippines. Approximately 870 km to the north of the February 27 earthquake is the source region of the magnitude 8.5 earthquake of November, 1922. This great quake significantly impacted central Chile, killing several hundred people and causing severe property damage. The 1922 quake generated a 9-meter local tsunami that inundated the Chile coast near the town of Coquimbo; the tsunami also crossed the Pacific, washing away boats in Hilo harbor, Hawaii. The magnitude 8.8 earthquake of February 27, 2010 ruptured the portion of the South American subduction zone separating these two massive historical earthquakes.
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February 27th, 2010
A massive magnitude-8.8 earthquake struck south-central Chile early on Saturday, killing at least 78 people, knocking down buildings and triggering a tsunami.
REUTERS/Pacific Disaster Center/Handout
TSUNAMI
A huge wave swept into the southern island of Juan Fernandez, and radio stations said it caused serious damage.
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