Applying planetary mapping methods to submarine environments: onshore-offshore geomorphology of Christiana-Santorini-Kolumbo Volcanic Group, Greece Item Type Article; text Authors Huff, A.E.; Nomikou, P.; Thompson, L.A.; Hooft, E.E.E.; Walker, I.J. Citation Huff, A. E., Nomikou, P., Thompson, L. A., Hooft, E. E. E., & Walker, I. J. (2021). Applying planetary mapping methods to submarine environments: Onshore-offshore geomorphology of Christiana-Santorini-Kolumbo Volcanic Group, Greece. Journal of Maps, 17(3), 111–121. DOI 10.1080/17445647.2021.1880980 Publisher Taylor and Francis Ltd. Journal Journal of Maps Rights Copyright © 2021 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (http://creativecommons.org/licenses/ by-nc/4.0/). Download date 01/10/2021 16:36:58 Item License https://creativecommons.org/licenses/by-nc/4.0/ Version Final published version Link to Item http://hdl.handle.net/10150/661217 Journal of Maps ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/tjom20 Applying planetary mapping methods to submarine environments: onshore-offshore geomorphology of Christiana-Santorini-Kolumbo Volcanic Group, Greece Alexandra E. Huff, Paraskevi Nomikou, Lisa A. Thompson, Emilie E. E. Hooft & Ian J. Walker To cite this article: Alexandra E. Huff, Paraskevi Nomikou, Lisa A. Thompson, Emilie E. E. Hooft & Ian J. Walker (2021) Applying planetary mapping methods to submarine environments: onshore- offshore geomorphology of Christiana-Santorini-Kolumbo Volcanic Group, Greece, Journal of Maps, 17:3, 111-121, DOI: 10.1080/17445647.2021.1880980 To link to this article: https://doi.org/10.1080/17445647.2021.1880980 © 2021 The Author(s). Published by Informa View supplementary material UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps Published online: 02 Mar 2021. Submit your article to this journal Article views: 2346 View related articles View Crossmark data Citing articles: 1 View citing articles Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tjom20 JOURNAL OF MAPS 2021, VOL. 17, NO. 3, 111–121 https://doi.org/10.1080/17445647.2021.1880980 Applying planetary mapping methods to submarine environments: onshore- offshore geomorphology of Christiana-Santorini-Kolumbo Volcanic Group, Greece Alexandra E. Huff a,b, Paraskevi Nomikou c, Lisa A. Thompson d, Emilie E. E. Hooft e and Ian J. Walker b,f aFulbright Greece, Fulbright US Student Program, Athens, Greece; bSchool of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA; cFaculty of Geology and Geo-Environment, National and Kapodistrian University of Athens, Athens, Greece; dArizona Geological Survey, University of Arizona, Tucson, AZ, USA; eDepartment of Earth Sciences, University of Oregon, Eugene, USA; fSchool of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ, USA ABSTRACT ARTICLE HISTORY Geologic maps are foundational products for natural hazard assessments but developing them Received 30 June 2020 for submarine areas is challenging due to a lack of physical access to the study area. In Revised 14 January 2021 response, submarine geomorphologic maps are used to provide geologic context and Accepted 19 January 2021 spatial information on landforms and related geo-hazards for risk management. These maps KEYWORDS are generated from remotely sensed data, e.g. digital elevation models (DEMs), which Mapping; geomorphology; introduce unique hurdles to submarine mapping. To address this issue, we produced a submarine; planetary; workflow for applying planetary geologic mapping methods to submarine data. Using this, methods; Santorini we created an onshore-offshore geomorphologic map of the Christiana-Santorini-Kolumbo Volcanic Group, Greece. This product can be used to enhance hazard assessments on Santorini, which is a tourist hot-spot at high risk for volcanically- and seismically-induced hazards. We present this workflow as a tool for generating uniform geomorphologic map products that will aid natural hazard assessments of submarine environments. 1. Introduction submarine environments (Baggeroer, 2001), and tech- nological growth in this area has enhanced assessment Maps are foundational tools for presenting research, of submarine hazards and risks. However, the inability communicating science, directing policy, and educat- to physically traverse the seafloor to identify wide- ing the public. Geologic maps typically display the spread lithologies limits the development of classic, spatial distribution, lithology (i.e. composition, grain lithology-based geologic maps, which are typically size, and bedding attributes), and age relationships used to contextualize hazards and communicate risk. of rock units and structural features (i.e. folds, faults, In response, the submarine community typically and joints). To address natural hazards, geologic prioritizes geomorphologic maps as a tool to aid maps can also identify past deposits, landforms, and characterization of submarine geology and natural events (e.g. earthquake locations, landslide head- hazards. Geomorphologic maps describe and classify scarps) and areas at risk for future events (e.g. volcanic landforms based on (1) landform morphometry, mor- vents, fault zones). Hazard maps made from a geologic phography, and hydrography, (2) lithology, structure, map display deposits and landforms distinctly associ- and sedimentology, and (3) geologic age and for- ated with certain hazards and identify areas of low, mation/alteration processes (e.g. Gustavsson et al., moderate, and high risk to public safety. Ultimately, 2006). In a submarine environment, investigations geologic maps place natural hazards in spatial and use remotely sensed bathymetry data to spatially con- geologic context and are essential for hazard textualize scientific results within the constraints of assessments. seafloor accessibility. Therefore, submarine geomor- Mapping of areas that were previously limited by phologic maps use seafloor relief and local sampling size, accessibility, nature preserves, and water cover methods to inform underlying lithology, sedimentol- are now being actively surveyed and characterized ogy, dynamic surface processes, geologic history of through advancements in remote sensing (Smith & the area, and related submarine hazards. Pain, 2009). Specifically, seafloor mapping technol- Submarine geomorphologic maps have inherent ogies facilitate the visualization and examination of limitations in the information they convey due to CONTACT Alexandra E. Huff aehuff@asu.edu School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1004, USA Supplemental data for this article can be accessed https://doi.org/10.1080/17445647.2021.1880980 © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 112 A. E. HUFF ET AL. the primary use of remotely sensed data and incor- The CSK VG and surrounding Aegean islands are poration of spatially constrained geologic character- at high risk for volcanically- and seismically-induced istics (i.e. lithology, sedimentology, structure). hazards, including earthquakes, volcanic eruptions, Submarine remote sensing products include multi- tsunami, and landslides. In 1650, the submarine vol- beam swath bathymetry, side-scan sonar, seismic cano Kolumbo exploded and breached the sea surface, reflection surveys, and remotely operated vehicle sending tsunami and pyroclastic flows toward neigh- (ROV) imagery (Micallef, 2011). Consequently, the boring islands, including Santorini (Nomikou, Carey following factors challenge submarine geomorpholo- et al., 2014; Ulvrova et al., 2016). In 1956, Santorini gic map production: was devastated by a 7.5 Mw earthquake sourced from a submarine fault near Amorgos Island (northeast of Santorini) (Brüstle et al., 2014; Nomikou et al., 2018; (1) data types, coverages, and resolutions limit the Okal et al., 2009). This earthquake was the largest of characterization of landforms; the century for Santorini, but every year the CSK (2) seafloor geologic data are often constrained to VG experiences multiple low magnitude earthquakes points, lines, and surface extrapolations from sourced from nearby faults that crisscross the seafloor. seafloor sampling methods such as drilling, geo- In 2011-2012, Santorini experienced a 14-month physical surveys, and ROV surveys, respectively; period of volcanic unrest during which the seafloor and rose in the northern part of the caldera from magmatic (3) field, submarine, and planetary geologists use inflation (Papoutsis et al., 2013; Parks et al., 2012), conflicting vocabulary (‘Geologic’ versus ‘Geo- submarine fumarole chemistry and sea temperatures morphologic’) to label these maps. changed dramatically (Tassi et al., 2013), and more than 50 low magnitude earthquakes per day were As a result, ‘the large majority of marine geomorpho- recorded (Feuillet, 2013; Papadimitriou et al., 2015). logic maps are thematic and interpretational rather than Volcanologists believed an eruption was imminent, holistic, scientificmaps’ (Micallef, 2011). As such,