Terrestrial laser scanning observations of geomorphic changes and varying lava lake levels at Erebus volcano, Antarctica

• Main Authors: Jones, LK, Kyle, PR, Oppenheimer, C, Frechette, JD, Okal, MH
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier BV 2015
• Subjects: Erebus; TLS; Lidar; Geomorphology; Lava lake; McMurdo Station; Dunbar; McIntosh; Lava Lake; Main Crater; Inner Crater; Antarc*; Antarctica
• Online Access: https://www.repository.cam.ac.uk/handle/1810/247889

A Terrestrial Laser Scanning (TLS) instrument was used to image the topography of the Main Crater at Erebus volcano each December in 2008, 2009, and 2010. Our high-spatial resolution TLS scans provide unique insights into annual and decadal scale geomorphic evolution of the summit area when integrated with comparable data collected by an airborne instrument in 2001. We observe both a pattern of subsidence within the Inner Crater of the volcano and an ~ 3 m per-year drop in the lava lake level over the same time period that are suggestive of decreasing overpressure in an underlying magma reservoir. We also scanned the active phonolite lava lake hosted within the Inner Crater, and recorded rapid cyclic fluctuations in the level of the lake. These were sporadically interrupted by minor explosions by bursting gas bubbles at the lake surface. The TLS data permit calculation of lake level rise and fall speeds and associated rates of volumetric change within the lake. These new observations, when considered with prior determinations of rates of lake surface motion and gas output, are indicative of unsteady magma flow in the conduit and its associated variability in gas volume fraction. This material is based upon work supported by the National Science Foundation (Division of Polar Programs) under Grants ANT0838817 and ANT1142083. The Optech ILRIS 3D TLS instrument was provided by the UNAVCO Polar group with support from NSF grant award ANT0723223. CO receives additional support from the NEC Centre for the Observation and Modeling of Earthquakes, volcanoes and Tectonics (COMET). We gratefully acknowledge the following for assisting with fieldwork on Erebus: Nelia Dunbar, Bill McIntosh, Aaron Curtis, Nels Iverson, Matt Zimmerer, Melissa Kammerer, Nial Peters, Kayla Iacovino, Yves Moussallam, Tehnuka Ilanko, Anna Barford, and Harry Keys. We also acknowledge tremendous logistical support from the staff and the civilian contractors working out of McMurdo station on behalf of the Division of Polar Programs of NSF. We ...