Recognizing the differences and similarities in approach between traditional engineering Fracture Mechanics and Seismology, this project describes an interdisciplinary program on "Experimental Seismology". This project utilizes advanced diagnostic methods, some of them developed through previous research funding, to study basic physical phenomena governing fault rupture. It aims to address some of the outstanding problems in Seismology pertaining to the influence of driving stress, fault strength and fault geometry inhomogeneities on the rupture process. The researchers also intend to strengthen the connection between laboratory observations and complex natural earthquakes which often occur in the presence of such inhomogeneities. The interdisciplinary nature of this research necessarily involves assigning priorities to the many goals within individual disciplines. In particular, two main characteristics are reflected in the design of the experiments. Firstly, the experimental design is intended to be as relevant as possible to the geophysical systems that they model. Secondly, the design is kept as basic as possible so that real-time data collection and analyses can produce, unequivocal, understanding regarding the phenomena under scrutiny. Typically, localized rupture conditions along earthquake faults are inferred from wave disturbances recorded at locations remote from the hypocenter. However, inversion of seismographic data is no substitute for direct in-situ observation on the rupture process. With the exception of the researchers recent work, and a few other isolated cases, mostly numerical and analytical models of fault behavior exist. This investigation may help resolve many controversies that exist in earthquake dynamics. In addition, it is expected that the proposed research program will result in the identification of new, exciting, and perhaps unexpected physical phenomena.
