GEOSCAN Search Results: Fastlink


TitleMicro-seismicity in the southwestern Yukon, Canada
AuthorMeighan, L N; Mazzotti, S; Cassidy, J
SourceSeismological Research Letters vol. 83, no. 2, 2012 p. 1
Alt SeriesEarth Sciences Sector, Contribution Series 20120042
MeetingSeismological Society of America, Annual Meeting; San Diego; US; April 17-19, 2012
Mediapaper; on-line; digital
RelatedThis publication is related to Meighan, L N; Mazzotti, S; Cassidy, J; (2012). Micro-seismicity in the southwestern Yukon, Canada, Seismological Society of America (SSA) 2012 Meeting Abstracts
File formatpdf
NTS115F/07; 115F/10
AreaCordillera; Yakutat; St.Elias Mountain; Chugach Mountain
Lat/Long WENS-141.0000 -140.7500 61.7500 61.2500
Subjectstectonics; geophysics; seismicity; array seismology; seismic surveys; seismic interpretations; tectonic interpretations; tectonic setting; tectonic environments; Duke River Fault; Denali Fault
ProgramTargeted Hazard Assessments in Northern Canada, Public Safety Geoscience
AbstractIn the summer of 2010, a new denser seismic array was deployed in the southwestern Yukon Territory, allowing for the first time detection of micro-seismicity in the region with more accurate locations and depth estimates. This dataset will provide a better understanding of the relationship between the micro-seismicity and the tectonics and surface structure of the northern Canadian Cordillera. This study region is a tectonically and seismically active area that represents a transition from strike-slip tectonics in the south to collisional tectonics in the Yakutat region. Rapid uplift, crustal thickening and high seismicity in the neighbouring St.Elias and Chugach Mountains is primarily due to the collision of the Yakutat block, a small oceanic-continental terrane, in the Gulf of Alaska that is moving northwestward with the Pacific plate along the North America western margin. Preliminary results using the new seismic array show for the first time a cluster of earthquakes trending in a north-east trending direction from just south of the Duke River fault (near 61.5N and 141W) to near the Denali Fault in the northeast. Detailed analysis and relocations is currently underway to examine the possible relationship with surface faults, and the possibility of inboard stress transfer. Preliminary statistical analyses of the micro-seismicity also show significantly different b-values of 1.1 ± 0.2 for the NE trending cluster and 0.8±0.1 for the Duke River fault. The northern and southern segments of the Denali fault have similar b-values of 0.9 ± 0.1. As well, we carried out a preliminary analysis of the aftershock sequence of the August 3rd 2011, M=4.4 earthquake located on the segment of the Denali Fault near the Canada-US border.