ABSTRACT:
We plan to install and operate a permanent seismic observatory illuminating the volume of the Homestake Mine from all six possible directions. We have chosen the Homestake DUSEL site because it offers a unique opportunity - the large volume of mine working of the deepest mine in North America is surrounded and underlain by literally hundreds of open bore holes, which can affordably be instrumented with accelerometers. We envision a seismic array that allows the community to image rapid dynamic changes in the rock mass. For instance, we will be able to estimate seismic parameters of events associated with dewatering, excavation, and various rock mechanics experiments, and estimate source kinematics caused by activity within or near the mine. Given the damage location of the event determined by the array, the rock mass can be back-excavated to find the source damage in the rocks. When found, a direct connection can be made between the damage process and seismic waves generated. This fundamental knowledge would be applicable to all sites, and help answer important questions concerning the energy budget of fracture growth and dynamics, local frictional behavior within a rock mass, seismic scaling laws, and interpretation of seismic moment tensors.
1 OUR IDEA
1.1 Transparent Earth at Homestake DUSEL
We are developing a deep in situ seismic observatory that will move us closer to the realization of rapid imaging of dynamical geo-processes at depth. The project is comprised of the installation of a unique three-dimensional seismic array, further research and development of unique MEMS-based downhole seismic instrumentation, and implementation of software to locate and characterize underground seismic events associated with various rock damage mechanisms within the Homestake Mine. Extensive mining provides access to large volumes of rock, and large blocks of virtually pristine rock are readily accessible for experiments requiring these conditions.
