Inside the Fault

摘要

The longest ongoing earthquake experiment in the world is extending its lead even further, with an international effort to drill a 2.1-kilometer deep pilot hole into California's famous San Andreas Fault. With drilling completed this summer near the central California town of Parkfield, scientists with the U.S. Geological Survey (USGS) and Stanford University (Stanford, CA) look forward to new insights that will help them better predict the timing and severity of earthquakes along the 800-mile fault. The pilot hole was a collaborative effort among the International Continental Scientific Drilling Program (ICSD - a multinational geo-sciences project based in Potsdam, Germany), the National Science Foundation (NSF) and USGS. A major objective of the pilot hole is to provide geological data for an even more ambitious effort called the San Andreas Fault Observatory at Depth (SAFOD). That project is now seeking federal funding to drill yet another borehole that will cross the San Andreas Fault four kilometers below the surface. Their mission is to answer fundamental questions about the physical and chemical processes controlling faulting and earthquake generation within a major plate-bounding fault.