9:15 AM - 9:30 AM
[MTT37-02] Recurring LP-events within a tidewater greenlandic glacier
Keywords:glacier, seismicity, Long-Period event
In July 2015 and July 2016, we conducted two passive seismic experiments at Bowdoin Glacier, an iceberg calving glacier in northwest Greenland. Using 5 - 8 station networks installed directly on ice or rock near the glacier, we observed thousands of LP events occurring every 10 minutes or less. With 20-30-s-long, low-frequency (< 2 Hz) monochromatic coda tails, and broadband, high-frequency (up to 20 Hz) onsets.
To understand source mechanisms of LP events at Bowdoin Glacier, we detect them by pattern matching and locate them with frequency-wavenumber analysis performed at two seismic arrays. This yields source locations near the calving front of the glacier near an active subglacial discharge channel. We report LP-events features, present temporal variations, and compare them to other available time-series (GPS, borehole water pressure, AWS measurements, and time-lapse photography), which, at this point, suggest fluid-filled cracking as the most likely source mechanism.