Antarctic Science 24(4), 367–376 (2012) & Antarctic Science Ltd 2012 doi:10.1017/S0954102012000193 Determination of geomorphological and volumetric variations in the 1970 land volcanic craters area (Deception Island, Antarctica) from 1968 using historical and current maps, remote sensing and GNSS M. BERROCOSO 1 , C. TORRECILLAS 2 *, B. JIGENA 1 and A. FERNA ´ NDEZ-ROS 1 1 Laboratorio de Astronomı ´a, Geodesia y Cartografı ´a, Universidad de Ca ´diz, Campus Rı ´o San Pedro s/n, Puerto Real, Ca ´diz 11510, Spain 2 Departamento de Ingenierı ´a Gra ´fica, Escuela Te ´cnica Superior de Ingenieros, Universidad de Sevilla, Av. De los Descubrimientos s/n, Seville 41092, Spain *torrecillas@us.es Abstract: During the nearly 40 years covered by the study, major height differences of over ± 25 m have been revealed in the volcanic landscape of the 1970 craters in Deception Island, an active volcano in the South Shetland Islands (West Antarctica). In the last 14 years, the mean volcanic filling rate has been 1 m yr -1 and the mean erosion rate has been -0.2 m yr -1 . There has been considerable landform modification mainly associated with landslide-induced accumulation, and erosion may indicate the craters’ fill over the next 30–40 years. Deception Island’s eruptions have been recorded since 1842. Special attention was paid to the zones affected by the most recent volcanic events and the geomorphological changes that have taken place in those zones since then (e.g. the 1970 volcanic craters area in the last episode occurring between 1967 and 1970). Historical maps (produced before and just after the 1970 eruption) were compared with maps plotted in 1992 and updated using a 2003 image from the Quickbird satellite and data obtained with Global Navigation Satellite System technology in 2006. Techniques used included both geodetic transformation and the geometric correcting of maps. Received 22 August 2011, accepted 23 January 2012, first published online 8 March 2012 Key words: Digital elevation model, geodetic transformations, geoid, GPS, volcanic erosion rate, volcanic sedimentation rate Introduction Deception Island (South Shetland Islands, West Antarctica) is a horseshoe-shaped Quaternary volcanic island with well- recorded geomorphic events related to recent eruptions. Historical eruptions took place in 1842, 1912, 1917, 1967, 1969 and 1970 (Smellie et al. 2002). During this period of time, the island’s geomorphic evolution has modified the inner shoreline and given rise to new volcanic edifices like cinder cones and maars and tuff cones principally formed during phreatomagmatic eruptions (Roobol 1973, Baker et al. 1975, Ortiz et al. 1992, Smellie 2001, 2002). Deception Island has been the site of a whaling station and several Antarctic stations since early in the 20th century. Accordingly, different maps and cartographic representations were produced which reflected the eruptions that were taking place, like Kendall’s map of 1829 (Roobol 1973), Brecher’s 1:10 000 maps of 1956, 1968 and 1970 (Brecher 1975), the 1:25 000 topographic map plotted by the British Directorate of Overseas Surveys, now Ordnance Survey International (OSI 1957) and the 1:25 000 topographic map plotted by the Spanish Army Geographical Service, now Army Geographical Centre (Centro Geogra ´fico del Eje ´rcito, CGE 1992). There are also some sketches (Hawkes 1961, Baker et al. 1975, Roobol 1982, Birkenmajer 1991, 1992) and other historical topographical small-scale maps, like the one plotted to a scale of 1:200 000 by the OSI in 1968 (OSI 1968). In 2006, the CGE published a new topographical map of Deception Island based on a Quickbird image georeferenced with almost one hundred control points calculated from a Global Positioning System (GPS) geodetic network called REGID (REd Geodesica Isla Decepcio ´n) (Berrocoso et al. 2006, 2008). The REGID network has been used to monitor the volcano since 1988–89 and now has 12 geodetic vertices. The results obtained from it show that, in terms of surface deformation, the highest current vertical and horizontal ground-surface deformation values are to be found in the areas known as the 1970 volcanic craters and Telefon Bay. To continue the monitoring of topographical changes on the island, we decided to establish as accurately as possible exactly what superficial changes have taken place in the 1970 volcanic craters since the most recent volcanic episode and determine their possible causes. Thanks to the absence of snow in the studied area during the greater part of the year, it was possible both to collect good field data and also to assess the changes that occurred each year. 367 https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0954102012000193 Downloaded from https://www.cambridge.org/core. IP address: 207.241.231.82, on 27 Jul 2018 at 01:32:29, subject to the Cambridge Core terms of use, available at