Data from subglacial instrumentation at Engabreen 2010-2011

This data comes from subglacial instrumentation installed in the tunnels beneath Engabreen, Norway. Additional (overlapping in time) datasets from a partner group of seismic and GPS instrumentation is available in a separate archive. For additional information, please see the related publication: Moore, P.L., et al., 2013, Glacier slip and seismicity induced by surface melt, Geology, 10.1130/G34760.1 Data are provided as raw (uncalibrated) output files, along with matlab scripts containing calibration information. The 2010 datasets extend from March 18, 2010 until June 11, 2010; 2011 datasets extend from May 6-24. In the first two weeks of each dataset, pump tests were conducted to investigate the response of the glacier to local water pressure perturbations. In 2010, data come from two different dataloggers, a Campbell CR10X and a Campbell CR1000. In 2011, datasets come from each of these two loggers as well as an Acoustic Emissions system. The included matlab scripts contain commands to load and parse data from the data files and to apply calibrations. The CR10X files output readings from the friction panel, described in the paper referenced above (and its associated online supplementary material). The panel measurements consist of two normal load cells, two shear load cells and two water-pressure transducers installed flush with the bed of the glacier. When calibrations from the matlab scripts are applied, the output yields kilopascals (kPa). NS1, NS2 = normal stress SS1, SS2 = shear stress WP1, WP2 = water pressure CR1000 files contain data from extensometers whose wires were fed through boreholes from he subglacial tunnel to the bed of the glacier, where anchors were embedded in basal ice or left on the glacier bed. Sampling interval in 2010 was 10 Hz, yielding very large files. The May 2010 data segment records some motion, but two extensometers had failed to work by this time. Output is in mm displacement. pot1, pot2, pot3: displacements in mm hammer: a boolean data string indicating whether a hammer-switch circuit was completed -- used to synchronize clocks with subglacial seismometers. The 2011 dataset includes a large number of files like enga066.dat and PRERUN066.txt. These are raw acoustic emissions files from a system also described in the paper referenced above. The system only recorded basic metrics from each AE hit that exceeded a nominal threshold, so there are no waveforms available. Each engaXXX.dat file contains a listing of these metrics from each hit, but contains only a timestamp that resets each time the system started a new file. Thus, the PRERUNXXX.txt file associated with each dat file contains the real time-string, from which timestamps are generated in the matlab script. Output from the script are two vectors: jtimeAE: a list of timestamps corresponding to times when an AE hit exceeded the threshold (40 dB) Amp: hit amplitude, in dB > 40.