NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: earthquake, geophysics, teleseismic observatory, Natural Hazards, passive seismology, network, geoscience

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. 5784. 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, we will produce an updated catalogue of earthquakes targeting more precise locations and depths, frequency, and magnitude range (including how large they could potentially be). In addition, we will periodically re-survey several existing geodetic monuments on either side of the Richardson Mountains to constrain the relative deformation across the range. Lastly, we 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 us 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 a small network of seismograph stations across Banks and Victoria islands, the Yukon North Slope, and communities within this region (see map attached). 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 and 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 are 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 GSC from the University of Ottawa, located at Nelson Head, Bar Harbour and Johnson Point. Further, the researchers 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 adopted from the US National Science Foundation a site in Tsiigehtchic, located at the Visitor Centre; this 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 are left behind. Example images of the site installations are included on page three of the attached supporting documentation. The results from this ongoing research project will be communicated at the Geoscience Forum in Yellowknife, as well as 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 researchers point out that results from our previous project was presented several times at the Yellowknife Geoscience Forum, as well as at the Tuktoyaktuk Science Day in 2019. The researchers continue to look for local outreach in the community for conducting the small-scale ground amplification and characterization study. This was postponed in year 2 (2023) due to the smoke conditions and fire conditions in Inuvik. This would 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 12 - August 15, 2024