Chinese earthquake provides lessons for futureJuly 22, 2008The May 12 Sichuan earthquake in China was unexpectedly large. Analysis of the area, however, now shows that topographic characteristics of the highly mountainous area identified the mountain range as active and could have pointed to the earthquake hazard. Topographic analysis can help evaluate other, similar fault areas for seismic risk, according to geologists from Penn State and Arizona State University. The researchers note that "the landscape itself encodes information about the rates and patterns of tectonic activity," in an advanced online publication of Nature Geosciences today (July 20). The ability to read these erosional landscapes is now good enough that researchers can use topographic analysis as a reconnaissance tool to identify areas of active rock uplift, according to Eric Kirby, associate professor of geosciences, Penn State. In remote mountainous areas, this approach can shed light on the activity of blind and hidden faults. Kirby, working with Kelin Whipple, professor, School of Earth and Space Exploration, Arizona State University, and Nathan Harkins, graduate student, geosciences, Penn State, used topographic analysis of the area of the Sichuan earthquake to suggest a way to refine existing maps of earthquake risk in other places. Previous studies using data from Global Positioning System satellites found the area had slow deformation rates that indicate modest strain and seismic hazard, but this description contradicts the impression given by the rugged mountains. Similar terrain in the Himalaya Mountains is associated with rapid convergence -- tectonic plates moving toward each other. Previously, Kirby and Whipple, focusing on geomorphic analysis, suggested that faults in the Sichuan region were active and were associated with regions of ongoing uplift of the mountains. "The 2008 earthquake struck on one of the faults identified with high rates of rock uplift," says Kirby. "Topographic analysis can have potentially important implications for anticipating the likely locations of events in this area." The researchers also believe that topography can indicate deformation of the crust at depth, even when short-term satellite measurements do not. For the Tibetan Plateau, this may be because crustal thickening occurs in an unusual way, through flow and deformation in the lower crust, rather than shortening of the upper crust. If this is correct, faults in the Longmen Shan range could be active, even without evidence of shortening across the mountain range. "Where shortening rates are slow and satellite data may be ambiguous, topographic analysis can help guide the identification of potential earthquake risk," says Kirby. The researchers looked at such things as anomalously steep river channel profiles extracted from digital elevation models, digital maps that represent changes in elevation of the land. They note that these methods were tested in areas where the actual tectonic activity levels were already known and that the Sichuan earthquake presents an ideal laboratory to further check the approach. Penn State |
|||||||||||||||||||||
| Related Earthquake Current Events and Earthquake News Articles On the crest of wave energy The ocean is a potentially vast source of electric power, yet as engineers test new technologies for capturing it, the devices are plagued by battering storms, limited efficiency, and the need to be tethered to the seafloor. Deep creep means milder, more frequent earthquakes along Southern California's San Jacinto fault With an average of four mini-earthquakes per day, Southern California's San Jacinto fault constantly adjusts to make it a less likely candidate for a major earthquake than its quiet neighbor to the east, the Southern San Andreas fault, according to an article in the journal Nature Geoscience. Global challenges and opportunities in fighting HIV/AIDS and neglected diseases Responding to the HIV/AIDS pandemic and tackling so-called neglected tropical diseases are the focus of the November/December 2009 edition of Health Affairs. Fortuitous research provides first detailed documentation of tsunami erosion Tsunamis are among the most-devastating natural calamities. These earthquake-generated waves can quickly engulf low-lying land and bring widespread destruction and death. They can deposit sand and debris far inland from where they came ashore. West Antarctic ice sheet may not be losing ice as fast as once thought New ground measurements made by the West Antarctic GPS Network (WAGN) project, composed of researchers from The University of Texas at Austin, The Ohio State University, and The University of Memphis, suggest the rate of ice loss of the West Antarctic ice sheet has been slightly overestimated. Tsunami evacuation buildings: another way to save lives in the Pacific Northwest Some time soon, a powerful earthquake will trigger a massive tsunami that will flood the Pacific Northwest, destroying homes and threatening the lives of tens of thousands of people, says Yumei Wang, a geotechnical engineer at the Oregon Department of Geology and Mineral Industries in Portland. Satellite data look behind the scenes of deadly earthquake Using satellite radar data and GPS measurements, Chinese researchers have explained the exceptional geological events leading to the 2008 Wenchuan Earthquake that killed nearly 90 000 people in China's Sichuan Province. Scientists obtain rocks moving into seismogenic zone An international group of scientists aboard the Deep-Sea Drilling Vessel CHIKYU, operated by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) for the Integrated Ocean Drilling Program (IODP), return from a 40-day scientific expedition off the shore of the Kii Peninsula, Japan on Oct. 10, 2009. San Andreas affected by 2004 Sumatran quake U.S. seismologists have found evidence that the massive 2004 earthquake that triggered killer tsunamis throughout the Indian Ocean weakened at least a portion of California's famed San Andreas Fault. Plastic surgeons should be part of disaster relief planning, response When a terrorist bomb explodes, a tornado rips through a town, a hurricane devastates a region, or wildfires ravage homes and businesses, plastic surgeons are not typically atop the list of emergency responders. More Earthquake Current Events and Earthquake News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||