| Summary: | 2020 Spring. Includes bibliographical references. The Mackenzie Mountains are an actively uplifting and seismogenic arcuate thrust belt lying within the Northwest Territories and Yukon, Canada. Seismic activity in the region is poorly constrained due to a historically sparse seismograph distribution. In this study, new data are analyzed from the 40-station, ~875 km-long Mackenzie Mountains temporary network (Baker et al., 2020) crossing the Cordillera-Craton region adjacent to and within the Mackenzie Mountains, in conjunction with Transportable Array and other sparsely distributed arrays in the region. Data from approximately August 2016 – August 2018 are processed and compared to the sparse-network earthquake catalog records maintained by the USGS and Natural Resources Canada. Using algorithms developed by Kushnir et al. (1990), Rawles and Thurber (2015), and Roecker et al. (2006), signals are identified and subsequently associated across the network to note potential events, estimate phase onsets, and resolve hypocenter locations. This study improves the regional earthquake catalog by detecting smaller-magnitude earthquakes and lowering the regional magnitude of completeness from Mc = 2.5 to 1.9. Within the Mackenzie Mountains and immediately surrounding areas we find 524 new events and additionally recommend an updated location for 185 previously cataloged events. Our b-value computation for the updated catalog (0.916 ± 0.08) likely indicates a relatively high level of regional differential stress. We identify the spatial distribution of earthquakes in the Mackenzie Mountains as diffuse, and offer far-field stress transfer as a mechanism for producing widespread reverse faulting observed in the region. Further, we associate regional seismicity with tectonic activity in the context of known faults and orogenic provinces such as the Richardson Mountains.
|
|---|