NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: physical sciences, earthquake, geophysics, teleseismic observatory, Natural Hazards, passive seismology

Objective(s): To better characterize tectonic activity and evolution across the study region through improved monitoring of earthquakes and GPS motions.

Project Description: This licence has been issued for the scientific research application No. 5616. This project aims to better characterize tectonic activity and evolution across the study region through improved monitoring of earthquakes and GPS motions. Using a temporary network of seismometers, the research team will produce an updated catalogue of earthquakes targeting more precise locations, depths, frequency, and magnitude range (including how large they could potentially be). In addition, the research team will periodically re-survey several existing geodetic monuments on either side of the Richardson Mountains to constrain the relative deformation across the range. Lastly, the team will conduct in-situ local ground motion amplification affects as a function of time for seismic stations across the region. Together, these new datasets will enable the team to improve the local seismic hazard model for the southwestern Canadian Arctic, including taking into account the affect of melting permafrost on the amplification of ground motions caused by local and regional earthquakes. This project requires the continued operation of small network of seismograph stations across Banks and Victoria islands, the Yukon North Slope, and communities within this region. These instruments record the ground motions from local, regional, and distant earthquakes. Each station consists of a sensor buried <1 m in the sediments or affixed to the bedrock, a data recorder, batteries in an electronics box, and solar panels. Each site is autonomous and no chemical products are used around the site. Seismic waves travel from earthquakes around the globe and are detected by the sensor; it is completely passive and does not cause any vibrations or noise. The stations are left in place for the duration of the project. The data is downloaded onto a disk during a yearly maintenance trip, and returned to the office where they can be processed, analyzed, archived, and made publicly accessible via the Internet. This submission includes stations adopted by the Geological Survey of Canada (GSCP) from the University of Ottawa, located at Nelson Head, Bar Harbour and Johnson Point. Further, the research team would like to co-locate seismic sensors in the communities of Ulukhaktok and Tuktoyaktuk with Canadian Hydrographic Service Tide Gauges (electronics would go inside their existing structure, and the seismometer would be placed immediately adjacent). Lastly, the GSC has adopted a site from from the US National Science Foundation in Tsiigehtchic, located at the Visitor Centre; this site is now included in this license request. Finally, one campaign GPS site, RICH_East, is included in this application. The equipment consists of a tripod (~1 m tall) and antenna (~20cm diameter disk) erected on top of the existing geodetic monument (either a cylindrical pin grouted into bedrock, or a circular marker affixed to the bedrock). A battery and recorder are left in place with the tripod to record for 3-5 days. After this period, all the equipment is picked up, and nothing but the existing monument pin is left behind. The results from this ongoing research project will be communicated at the Geoscience Forum in Yellowknife, in the Yukon, in addition to national and international conferences. Plain language summaries of results (i.e., updates to local hazard models, earthquake catalogues, etc.,) will be communicated to the communities and councils through various means, including public lectures and Science Day events and activities (e.g., the past Tuktoyaktuk Science Day). The research team points out that results from the previous project were presented several times at the Yellowknife Geoscience Forum, as well as at the Tuktoyaktuk Science Day in 2019. The research team seek in year 2 onwards of this program to include a local community member in carrying out small-scale ground amplification and characterization surveys using a separate instrument, called a Tromino. This would directly contribute to the objective of classifying the time-dependent behaviour of changing permafrost on local site characteristics. The fieldwork for this study will be conducted from July 21, 2023 to August 31, 2023.