Evidence for a lava lake on Mt. Michael volcano, Saunders Island (South Sandwich Islands) from Landsat, Sentinel-2 and ASTER satellite imagery

Abstract Mt. Michael is an active stratovolcano on Saunders Island in the South Sandwich Islands; a remote, oceanic island arc in the southern Atlantic Ocean, bordering the Southern Ocean. The arc contains the only active volcanoes in the South Georgia and South Sandwich Islands British Overseas Territory, yet little is known of their activity. Despite lava lakes being extremely rare with only a few global examples, previous analyses of satellite AVHRR imagery of Mt. Michael in the 1990s showed persistent thermal anomalies not associated with magma overflowing the crater. This suggested the existence of a lava lake inside Mt. Michael's crater. However, their study relied on 1 km resolution imagery, and there have been no long-term investigations to determine if this is a persistent feature. In-situ observations of Mt. Michael are extremely difficult given the location. We used Landsat, Sentinel-2 and ASTER satellite data to monitor activity and detect thermal anomalies within the crater. Persistent volcanic plumes and eruptions were identified throughout the thirty-year period studied. On all 15 occasions that a suitable satellite image was available a thermal anomaly within the crater was detected in the high transmissivity shortwave infrared bands (SWIR) centred on 1.65 μm and 2.2 μm. Pixel-integrated surface temperatures over the crater floor yield temperatures of 284–419 °C; comparable to lava lakes elsewhere. Unmixing these temperatures using the dual-band method reveals a molten lava component at basaltic temperatures (989–1279 °C) among a cooler crust. This is the first evidence for a lava lake within Mt. Michael from data that can resolve the crater floor, and the first evidence for magmatic temperatures. As thermal anomalies were detected in all images showing the crater, we suggest that the lava lake is a common and persistent feature.

[1]  D. Rothery,et al.  Volcano monitoring using short wavelength infrared data from satellites , 1988 .

[2]  Matthew Blackett,et al.  An Overview of Infrared Remote Sensing of Volcanic Activity , 2017, J. Imaging.

[3]  M. Caillet,et al.  Field temperature measurements at Erta'Ale Lava Lake, Ethiopia , 2002 .

[4]  Peter W. Webley,et al.  Analyzing the Eyjafjallajökull 2010 eruption using satellite remote sensing, lidar and WRF‐Chem dispersion and tracking model , 2012 .

[5]  R. B..  South Sandwich Islands , 1932, Nature.

[6]  R. Branham.  Scientific data analysis , 1990 .

[7]  J. R. Jensen.  Remote Sensing of the Environment: An Earth Resource Perspective , 2000 .

[8]  M. Patrick,et al.  Synthesis A spaceborne inventory of volcanic activity in Antarctica and southern oceans, 2000–10 , 2013, Antarctic Science.

[9]  S. Day,et al.  Volcanic evolution of the South Sandwich volcanic arc, South Atlantic, from multibeam bathymetry , 2013 .

[10]  Maria Fabrizia Buongiorno,et al.  Error analysis of subpixel lava temperature measurements using infrared remotely sensed data , 2012 .

[11]  Paul G. Lucey,et al.  Radiative temperature measurements at Kupaianaha Lava Lake, Kilauea Volcano, Hawaii , 1993 .

[12]  Clive Oppenheimer,et al.  Lava flow cooling estimated from Landsat Thematic Mapper infrared data: The Lonquimay Eruption (Chile, 1989) , 1991 .

[13]  W. Paul Menzel,et al.  Determining diurnal variations of land surface emissivity from geostationary satellites , 2012 .

[14]  D. Rothery,et al.  Using the Landsat Thematic Mapper to detect and monitor active volcanoes: An example from Lascar volcano, northern Chile , 1987 .

[15]  R. Wright.  MODVOLC: 14 years of autonomous observations of effusive volcanism from space , 2015, Special Publications.

[16]  Matthew Blackett,et al.  Review of the utility of infrared remote sensing for detecting and monitoring volcanic activity with the case study of shortwave infrared data for Lascar Volcano from 2001–2005 , 2013 .

[17]  Clive Oppenheimer,et al.  Mass flux measurements at active lava lakes: Implications for magma recycling , 1999 .

[18]  S. Cronin,et al.  Variable conditions of magma storage and differentiation with links to eruption style at Ambrym volcano, Vanuatu , 2016 .

[19]  M. Burton,et al.  Degassing dynamics of basaltic lava lake at a top-ranking volatile emitter: Ambrym volcano, Vanuatu arc , 2016 .

[20]  Carlos Roberto de Souza Filho,et al.  Monitoring volcanic thermal anomalies from space: Size matters , 2011 .

[21]  Clive Oppenheimer,et al.  Thermal distributions of hot volcanic surfaces constrained using three infrared bands of remote sensing data , 1993 .

[22]  T. Thordarson,et al.  Interactions between lava and snow/ice during the 2010 Fimmvörðuháls eruption, south-central Iceland , 2012 .

[23]  R. Lyon,et al.  Infrared spectral returns and imagery of the earth from space and their application to geologic problems. , 1965 .

[24]  P. E. Baker,et al.  A Survey of the South Sandwich Islands , 1964, Nature.

[25]  G. Tyrrell.  Report on Rocks from West Antarctica and the Scotia Arc , 1945 .

[26]  J. Dozier.  A method for satellite identification of surface temperature fields of subpixel resolution , 1981 .

[27]  H. Tazieff.  Permanent lava lakes: observed facts and induced mechanisms , 1994 .

[28]  R. Campion.  New lava lake at Nyamuragira volcano revealed by combined ASTER and OMI SO2 measurements , 2014 .

[29]  David P. Roy,et al.  The global Landsat archive: Status, consolidation, and direction , 2016 .

[30]  Alexander Berk,et al.  MODTRAN6: a major upgrade of the MODTRAN radiative transfer code , 2014, Defense + Security Symposium.

[31]  A. Harris.  Thermal Remote Sensing of Active Volcanoes: A User's Manual , 2013 .

[32]  F. Guern,et al.  Erta'ale lava lake: heat and gas transfer to the atmosphere , 1979 .

[33]  J. Smellie,et al.  Discovery of a recurrent lava lake on Saunders Island (South Sandwich Islands) using AVHRR imagery , 2001 .

[34]  J. Campbell.  Introduction to remote sensing , 1987 .