| Description |
The Wasatch Plateau region of Central Utah contains multiple sources of seismic activity caused by a complicated mix of extensional tectonics and a long history of coal mining induced seismicity (MIS). This combination of seismic source types has made it difficult to study this region effectively as conclusions about regional structure, seismic hazard, and mine planning rely on knowing the causes of the events within an earthquake catalog. Using a catalog of 6,402 events recorded at University of Utah Seismograph Stations broadband seismic station SRU between mid-1998 and the end of 2011, this study aims to identify seismic event types in this region through a combination of methods. After updating the event locations in the catalog using more detailed velocity models and a newer location algorithm, all events in the catalog are cross-correlated with each other to quantify the level of waveform similarity. Clusters of similar waveforms are determined with a single-link clustering algorithm in a computer program called Detex. The locations, depth distributions, first motions, and spectral content of these clusters are then compared to clusters of known source types to determine whether the events in each cluster are MIS, tectonic earthquakes, or ambiguous. From this analysis, I determine that this study area contains 5,227 events in 38 clusters that are MIS, 310 events in 46 clusters that are not a result of mining operations, and 865 events that have unknown source types. The resulting catalog reveals the existence and extent of tectonic activity taking place within the mine boundaries in the Central Wasatch Plateau. |
