A geophone wireless sensor network for investigating glacier stick-slip motion

• Main Authors: Martinez, Kirk, Hart, Jane K., Basford, Philip J., Bragg, Graeme, Ward, Tyler, Young, David S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: glacier; Iceland
• Online Access: https://eprints.soton.ac.uk/412213/; https://eprints.soton.ac.uk/412213/1/geophone.pdf

We have developed an innovative passive borehole geophone system, as part of a wireless environmental sensor network to investigate glacier stick-slip motion. The new geophone nodes use an ARM Cortex-M3 processor with a low power design capable of running on battery power while embedded in the ice. Only data from seismic events was stored, held temporarily on a micro-SD card until they were retrieved by systems on the glacier surface which are connected to the internet. The sampling rates, detection and filtering levels were determined from a field trial using a standard commercial passive seismic system. The new system was installed on the Skalafellsjökull glacier in Iceland and provided encouraging results. The results showed that there was a relationship between surface melt water production and seismic event (ice quakes), and these occurred on a pattern related to the glacier surface melt-water controlled velocity changes (stick-slip motion). Three types of seismic events were identified, which were interpreted to reflect a pattern of till deformation (Type A), basal sliding (Type B) and hydraulic transience (Type C) associated with stick-slip motion.