Microseismic icequake catalogue, Rutford Ice Stream (West Antarctica), November 2018 to February 2019 ...

• Main Authors: Kufner, Sofia-Katerina, Brisbourne, Alex, Smith, Andrew, Hudson, Thomas, Murray, Tavi, Schlegel, Rebecca, Kendall, John, Anandakrishnan, Sridhar, Lee, Ian
• Format: Dataset
• Language: English
• Published: UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation 2020
• Subjects: "EARTH SCIENCE","CRYOSPHERE","GLACIERS/ICE SHEETS","GLACIER MOTION/ICE SHEET MOTION"; "EARTH SCIENCE","CRYOSPHERE","GLACIERS/ICE SHEETS"; "EARTH SCIENCE","SOLID EARTH","SEISMOLOGY"; BEAMISH; West Antarctica; glacier bed; ice stream; icequake; microseismicity; Hudson; Rutford; Rutford Ice Stream; Antarc*; Antarctica; Ice Sheet
• Online Access: https://dx.doi.org/10.5285/b809a040-8305-4bc5-baff-76aa2b823734; https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01432

This dataset contains ASCII files with hypocenter information, event times and magnitudes for 227029 micro-earthquakes with a magnitude range from -2.0 to -0.3 recorded from a 35-station seismic network located ~40 km upstream of the grounding line of Rutford Ice Stream, West Antarctica. For 87910 of these events, earthquake focal mechanisms (strike/dip/rake) are available. The seismic network, which recordings are the base for the event catalogue, broadly formed a rectangle with 1 km station spacing. Details on the station locations, instrument types and operation periods are included in these data files. The event catalogue encloses the geographic region between 084.142 to 083.760 degrees West and 78.204 to 78.113 degrees South. Events are located between 1.553 and 2.416 km depth. Recording took place between 20th November 2018 and 16th February 2019. The spatio-temporal arrangement of these micro-earthquakes can be used to characterize frictional properties at the ice-bed interface of Rutford Ice Stream. ... : Event locations were gained from the continuous passive seismic records using the QuakeMigrate (Hudson et al., 2019; J. D. Smith et al., 2020) and Nonlinloc (Lomax et al., 2000) software. A two-layer velocity model (firn layer above an ice layer) according to E. C. Smith et al. (2015) was used in the Nonlinloc location step. Based on Nonlinloc locations, we accept only events with a total root-mean-square (RMS) value of 0.02 s, a maximum azimuthal gap of 280 degrees, maximum 10% of picks with a P/S residual larger than 0.02 s/0.2 s and at least 3 P picks and 2 S picks for the final event catalogue. We account for the movement of the seismic stations relative to the bed due to ice flow by shifting each event in the final catalogue downstream. Rutford Ice Stream moved ~94 m downstream during the 90 day survey period, whereas our stations are specified at fixed locations during event location, clearly evidencing the necessity for such a shift. We perform this shift by calculating the stations' locations at the ...