Deception Island is the largest volcano in the actively extending Bransfield Basin, a marginal basin situated behind the extinct South Shetland Islands arc. Deception Island has been well studied but its submerged flanks have not. A multibeam bathymetry survey was conducted around the island in 2005. Data from the flooded caldera show no evidence for recent localized resurgence. The gently-sloped bottom of the caldera basin is consistent with either a broad zone of resurgence on its east side associated with trap door deformation or with higher rates of sediment supply from the east side of the island. Around the island, numerous tectonic and volcanic features on the volcano's east and west flanks are nearly all aligned with the regional strike (~060°) of the Bransfield rift and there is very little evidence for the other fault populations that have been identified on the island. We infer that models that link the ongoing tectonic development of Deception Island to complex regional tectonics are less likely than models in which the dominant regional extension in Bransfield Strait is modulated by the local effects of caldera collapse and possibly a small right-lateral transfer zone offsetting the primary extension axes in the Central and Western Bransfield Basins.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102008001673

Bathymetric constraints on the tectonic and volcanic evolution of Deception Island Volcano, South Shetland Islands

Volcano-tectonic dynamics of Deception Island (Antarctica): 27 years of GPS observations (1991–2018)

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 15 explosive eruptive events registered over the past two centuries. Recent eruptions (1967, 1969 and 1970) and volcanic unrest episodes in 1992, 1999 and 2014–15 demonstrate that the occurrence of future volcanic activity is a valid and pressing concern for scientists, logistic personnel and tourists that are visiting or are working on or near the island. Over the last few decades, intense research activity has been carried out on Deception Island to decipher the origin and evolution of this very complex volcano. To that end, a solid integration of related scientific disciplines, such as tectonics, petrology, geochemistry, geophysics, geomorphology, remote sensing, glaciology, is required. A proper understanding of the island9s evolution in the past, and its present state, is essential for improving the efficiency in interpreting monitoring data recorded during volcanic unrest periods and, hence, for future eruption forecasting. In this chapter, we briefly present Deception Island9s most relevant tectonic, geomorphological, volcanological and magmatic features, as well as the results obtained from decades of monitoring the island9s seismic activity and ground deformation.

Chapter 7.1 Deception Island

During the 2007-08 Spanish Antarctic campaign, two moorings of bottom pressure sensors were carried out over a ten week period. This paper presents the results of the tidal analysis from sea level records obtained at Deception and Livingston islands (South Shetland Islands, Antarctica). The main objective of this paper is to present a detailed study of the tidal characteristics at these two islands, for which statistical and harmonic analysis techniques are applied to the tidal records. A geodetic network was used to reference the pressure sensors. Geometric levelling, with an accuracy of 1 mm, allowed us to link the tidal marks with geodetic vertices located on Livingston and Deception islands. The amplitudes and phase lags obtained by harmonic analysis are compared to the harmonic constants of several coastal stations and co-tidal and co-range charts. Results show an evident influence of tides in the sea level signal, with a clear mixed semi-diurnal behaviour and a daily inequality between high and low waters. Measurements of salinity and temperature were made using electronic sensors. Results from this study showed that salinity and temperature were strongly influenced by tides. Seawater temperature varied in a manner that was consistent with the time series of residual bottom pressure.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S095410201100068X

Study of tides and sea levels at Deception and Livingston islands, Antarctica

Following more than 25 years of exploration and research since the last regional appraisal, the number of known subaerially exposed volcanoes in the northern Antarctic Peninsula region has more than trebled, from less than 15 to more than 50, and that total must be increased at least three-fold if seamounts in Bransfield Strait are included. Several volcanoes remain unvisited and there are relatively few detailed studies. The region includes Deception Island, the most prolific active volcano in Antarctica, and Mount Haddington, the largest volcano in Antarctica. The tectonic environment of the volcanism is more variable than elsewhere in Antarctica. Most of the volcanism is related to subduction. It includes very young ensialic marginal basin volcanism (Bransfield Strait), back-arc alkaline volcanism (James Ross Island Volcanic Group) and slab-window-related volcanism (seamount offshore of Anvers Island), as well as volcanism of uncertain origin (Anvers and Brabant islands; small volcanic centres on Livingston and Greenwich islands). Only ‘normal’ arc volcanism is not clearly represented, possibly because active subduction virtually ceased at c. 4 Ma. The eruptive environment for the volcanism varied between subglacial, marine and subaerial but a subglacial setting is prominent, particularly in the James Ross Island Volcanic Group.

Chapter 3.2a Bransfield Strait and James Ross Island: volcanology

Deception Island (62.93° S, 60.57°W) is one of the few active volcanoes in the Antarctica, whose most recent eruptions took place in 1842, 1967, 1969 and 1970. In the following paper geodetic investigations carried out in this area during the last years are described. During the continuous Spanish campaigns in Antarctica, several scientific groups have developed different projects in order to control deformation the island suffers as a result of its volcanic activity. With this purpose, a geodetic network has been designed and improved. Nowadays, the network consists of twelve stations around Port Foster which are provided with WGS-84 geodetic coordinates with respect to the ITRF2000, and another station at the Spanish Base Juan Carlos I on Livingston Island. Time analysis of these coordinates will lead us to get the horizontal deformation model. On the other hand, a levelling network has been designed to obtain the vertical deformation model. This network is denser in those areas where the volcanic activity is stronger, as at Fumarole Bay and the Hill of Obsidians. GPS, levelling and gravimetric measurements have also been collected in secondary points to obtain an experimental geoid model which makes possible an adequate reference frame for physical applications.

Geodetic Research on Deception Island

Deception Island (63° S, 60° W) is situated in the South Shetland Islands, and it is the main active volcano in the Bransfield Strait, with recent eruptions in 1842, 1967, 1969 and 1970. Its volcanic and seismic activity has been monitored from 1986 to study the geodynamic activity on the island. In this paper we present the objectives and some results obtained in DECVOL project, a crossdisciplinary study which was planned to evaluate the volcanic status of the island after the crisis occurred during the 1998/1999 campaign, as well as the goals and activities which have been carried out in the framework of GEODEC project, a multidisciplinary project to continue with the studies on the island.

M. Eva Ramírez

Papers

Geodetic Research on Deception Island

Geodynamical Studies on Deception Island: DECVOL and GEODEC Projects