Richard A. Kerr
Can Earth's crust fracture along gently tilted faults when it is pulled apart? The question provoked a debate at this year's Geological Society of America meeting in New Orleans. Geologists studying the rocks of the American Southwest say the evidence of such low-angle faulting is beyond dispute. Theorists who calculate how rocks should behave under stress say that the process simply can't happen; the geologists must be misinterpreting their observations.