Fuzzy Logic Approach on Seismic Event Location

Seismic events (e.g. induced seismicity in and around underground mining) are frequently, poorly located because recording is restricted to small aperture arrays at large distances from the event. In order to resolve the location problem, we used a fuzzy logic algorithm to increase stability in locating seismic events. We used P-P, S-S, and S-P time-travel intervals for constructing a modified G matrix which was regrouped into two matrices and solved the matrix by using a forward method instead of an inverse method. These matrices were mapped into the fuzzy logic space with measured uncertainties in terms of deviations in wave velocities. Locations of the example earthquakes were based on results of logic outputs in logic space by searching a gridded area. We found that the epicenter coordinates in a better spatial resolution by the intersection operation and a wider membership function must be used in the technique with intersection operation to locate the event more precisely. Although regular location programs do not yield satisfactory results in locating an event that occurs out of the network, our technique with fuzzy logic approach works especially well for the seismic events that occur out of the seismic network.