DAVID PARKER / SCIENCE PHOTO LIBRARY DAVID PARKER / SCIENCE PHOTO LIBRARY
Parkfield earthquake prediction experiment. Dr Richard Clymer operates a VIBROSEIS truck. It produces artificial S (shear) waves of a precise frequency which can be used to probe the underlying rock structures in a manner similar to sonar. The vibrations from the 26 tonne truck are transmitted to the ground via a baseplate (visible between the wheels). The returning signals are picked up by a nearby network of 10 seismometers. Seismologists have predicted that an earthquake of around magnitude 6 will occur on the San Andreas fault at Parkfield before 1993. Dozens of researchers have made the village the most heavily instrumented earthquake region in the world.
Model release not available. Property release not required.