2010 Science News of the Year: Earth
By Science News
Credit: Alvaro Ybarra Zavala/Getty Images
Inside the Haiti quake
Some 230,000 Haitians died when a magnitude-7 earthquake struck just outside Port-au-Prince on the afternoon of January 12. Scientists from around the world scrambled to the scene (SN Online: 1/16/10) to assess which fault had ruptured and whether more people were at risk. Early ideas held that the quake had broken along the well-known Enriquillo-Plantain Garden fault, which divides the Caribbean and North American tectonic plates. But U.S. Geological Survey scientists found no evidence of a large surface rupture there, instead spotting corals west of Port-au-Prince that had been lifted by the quake. Researchers concluded that most of the movement had been along a previously unknown fault (SN Online: 8/11/10), now called the Léogâne. If that’s correct, the strain that has accumulated in the last few centuries on the Enriquillo-Plantain Garden fault has not been released, and seismic hazard in Haiti remains high. Because such a large quake occurred without much surface rupture, geologists may need to rethink how to identify past quakes in the rock record, one team suggests in a special issue of Nature Geoscience.
Knocked for a loop A magnitude-8.8 earthquake in Chile tilts Earth’s axis a few centimeters and shortens the day, models suggest (SN Online: 3/3/10).