This dataset contains subaquatic passive seismic recordings taken in September 2021 at 88 locations off Tuktoyaktuk Island as well as in a small lake (“Lake 3”) between the villages of Tuktoyaktuk and Inuvik, Northwest Territories, Canada. The measurements were part of the “Mackenzie Delta Permafrost Field Campaign” (mCan2021) within the “Modular Observation solutions for Earth Systems” (MOSES) program. Data is from a seismic intermediate-bandwidth seismic sensor lowered for few minutes to the bottom of the sea and lake, respectively, and from underwater short-period sensors deployed for a few days. The aim of the study was to determine the depth of the subaquatic permafrost (local lake and oceanic locations). Raw data is provided in proprietary “Cube” format and standard mseed format.
During the 2018 “Mackenzie Delta Permafrost Field Campaign” (mCan2018), a test campaign within the “Modular Observation solutions for Earth Systems” (MOSES) program, ambient seismic noise recordings at the sea bottom were acquired along two 300 m long transects from the shoreline to shallow marine area close to Tuktoyaktuk Island (Canada). In total, 21 measurements were taken. Raw data is provided in proprietary “Cube” format and standard mseed format.
Schematic overview of a typical terrestrial and shallow-marine permafrost landscape during summer and winter.
Permafrost is defined as ground that remains continuously at or below 0°C for at least two consecutive years; some 24% of the land surface in the northern hemisphere is classified as permafrost. This schematic figure (summer) pictures a terrestrial and shallow marine permafrost system. A permafrost landscape is characterized by its large heterogeneity with morphological permafrost-related features such as polygonal patterned ground with underlying ice wedges, thaw ponds, thermokarst lakes, and wetland areas. During winter, the terrestrial landscape is covered with snow, and water bodies and the ocean are typically covered with ice.The last pictures shows schematically the fluxes (not scaled) that occur between the terrestrial and marine environment and atmosphere.
In August and September 2013, 17 shallow ocean bottom seismograph (S-OBS) stations and 8 land stations had been deployed on and around Muostakh Island (Laptev Sea, Russia) for a time period of 24 days.
The specifically designed underwater recording equipment consists of a low-power digital recorder, a standard 4.5Hz 3-component geophone, and a battery pack. These components are enclosed in a watertight cylindrical container safe for operation down to 100m water depth. Land stations were also equipped with 4.5 Hz 1C-geophones as well as with batteries. All instruments recorded continuously with 200 samples per second (sps). The stations were deployed along two profiles covering a region of 8 km x 8 km.
The tilt of the geophone inside the S-OBS influences the sensor characteristics. Since the orientation and tilt at the ocean bottom was unknown, approximately every 24 hours a calibration signal (a sequence of step-functions) was applied to the sensors of the ocean stations. This might be used to recover the actual sensor characteristics (eigenfrequency and damping).
The dataset contains 1) a info-folder with a) a README file; b) a file containing the times when calibration signals occurred (format: recorder_ID - date - time); c) the station table (ASCII; recorder_ID - latitude - longitude - (water)depth); d) a map of the region with the locations of the stations; 2) raw CUBE-formatted data; 3) converted mini-seed-formatted data (hourly files).