© Ben Brooks, SOEST/UHMBen Brooks, 'O. Ozcacha and Todd Ericksen stand next to one of the GPS stations that was used in the study.
The region east of the central Andes Mountains has the potential for larger scale earthquakes than previously expected, according to a new study posted online in the May 8th edition of Nature Geoscience. Previous research had set the maximum expected earthquake size to be magnitude 7.5, based on the relatively quiet history of seismicity in that area. This new study by researchers from the University of Hawaii at Manoa (UHM) and colleagues contradicts that limit and instead suggests that the region could see quakes with magnitudes 8.7 to 8.9.Benjamin Brooks, Associate Researcher in the Hawaii Institute of Geophysics and Planetology in the School of Ocean and Earth Science and Technology at UHM and colleagues used GPS data to map movement of the Earth's surface in the Subandean margin, along the eastern flank of the Andes Mountains. They report a sharp decrease in surface velocity from west to east. "We relate GPS surface movements to the subsurface via deformation models", says Brooks. "In this case, we use a simple elastic model of slip on a buried dislocation (fault) and do millions of Monte Carlo simulations to determine probability distributions for the model parameters (like slip, width, depth, dip, etc.)." From these data, the researchers conclude that the shallow section in the east of the region is currently locked in place over a length of about 100 km, allowing stress to build up as the tectonic plates in the region slowly move against each other. Rupture of the entire locked section by one earthquake could result in shaking of magnitudes up to 8.9, they estimate.
This project is a long-term collaborative effort between UHM, Ohio State University, Arizona State University, the Bolivian Instituto Geografico Militar (IGM), the Bolivian Seismological Observatory (Observatorio San Calixto), the Universidad Nacional de Cuyo (Argentina), and University of Memphis. The project's general name is the Central and Southern Andes Project (CAP).
Comment: Excerpt from
Forget About Global Warming: We're One Step From Extinction! by Laura Knight-Jadczyk
One final point. There have been reports that Earth is not the only planet being hit by "global warming". Might it be possible that this apparently widespread change of "climate" in the solar system is linked to an incoming comet cloud? We do not know and are sorely lacking in the means to acquire data to refine or reject the working hypothesis. Perhaps someone else out there does have the means. Whatever the explanation for a generalized warming of several planets, it is clear that we know very little about the fundamental mechanisms behind it. We are a speck in the universe, a drop in an ocean more vast, more complex, and more mysterious than we can imagine.