Tribology in the News

by Kiko Matsing

Haiti’s earthquake: The dangers aren’t over as tectonic plates readjust
by McClatchy-Tribune News Service at http://www.cleveland.com

Haiti Earthquake Map

Haiti lies on the margin between the North American and Caribbean plates, which are grinding past each other in an east-west direction at a speed of about an inch a year, said Ross Stein, a geophysicist with the U.S. Geological Survey in Menlo Park, Calif.

In the big picture, these plates drift smoothly around the planet. But zoom in to fault lines around their borders and whole sections of earth jerk, stick and slip. On Jan. 12, the fault probably displaced the ground by 2 to 3 feet, Stein said. That’s an insignificant distance on the scale of the continents, but it’s enough to topple a capital.

The section of fault that ruptured near Port-au-Prince had been “locked” since 1751, Stein said. That was when the last big earthquake was recorded there — a lesser disaster because of a much smaller population.

“If you’d gone by recent occurrences of small to moderate earthquakes, you’d have gotten this misimpression that this is a pretty quiet area,” he said. But it was the proverbial calm before the storm.

When geologists describe an area as locked, what they mean is stuck, Stein explained. “It’s really a product of friction,” he said. “If faults were made of Teflon, we wouldn’t have any earthquakes.”

Toyota recalls 2.3M US vehicles to fix gas pedals
from The Associated Press

Toyota Accelerator Pedal

Toyota said Thursday it is recalling 2.3 million vehicles in the U.S. to fix accelerator pedals that can become stuck, the latest in a string of quality problems that have bedeviled the Japanese automaker…

In a letter to federal safety officials dated Thursday, Toyota said the problem appeared to be related to the potential build-up of condensation on sliding surfaces in the accelerator system that helps drivers push down or release the gas pedal.

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