Active tectonics on Deception Island (West-Antarctica): A new approach by using the fractal anisotropy of lineaments, fault slip measurements and the caldera collapse shape

Abstract

The tectonic field on Deception Island (South Shetlands, West Antarctica) is determined from structural and fractal analyses. Three different analyses are applied to the study of the strain and stress fields in the area: (1) field measurements of faults (strain analysis), (2) fractal geometry of the spatial distribution of lineaments and (3) the caldera shape (stress analyses). In this work, the identified strain field is extensional with the maximum horizontal shortening trending NE-SW and NW-SE. The fractal technique applied to the spatial distribution of lineaments indicates a stress field with S HMAX oriented NE-SW. The elliptical caldera of Deception Island, determined from field mapping, satellite imagery, vents and fissure eruptions, has an elongate shape and a stress field with S HMAX trending NE-SW.

Determination of volumetric variations and coastal changes due to historical volcanic eruptions using historical maps and remote-sensing at Deception Island (West-Antarctica)

“…The inner shoreline is irregular and elongated NW-SE. The caldera boundary and the collapse scarp affect pre-caldera deposits and the location of post-caldera eruptive centres and cinder cones (Smellie, 2001(Smellie, , 2002Pérez-López et al, 2007). Postcaldera eruptions have covered and extensively modified the inner shoreline.…”

“…The island lies in a strike-slip stress regime (González-Casado et al, 2000) with the maximum horizontal stress (S HMAX ) trending NE-SW. The volcanic sequence that built up the island evolved from submarine pillow lavas to subaerial eruptions, mainly Strombolian and phreatomagmatic (Maestro et al, 2007;Pérez-López et al, 2007), indicating that Deception Island evolved through the collapse of a huge volcanic edifice under a regional stress regime with S HMAX oriented NE-SW. This regional stress produced movement on oblique-normal and normal faults, trending NNE-SSW to ENE-WSW, due to the interaction between the regional tectonic regime of the Bransfield Strait (NE-SW) and the dynamics of the magma chamber emplacement within the island.…”

Geodetic implications on block formation and geodynamic domains in the South Shetland Islands, Antarctic Peninsula

“…The upper crustal structure of the area comprises continental crust north of Deception Island and more basic crust to the south (Muñoz-Martín et al, 2005). The tectonic setting of the volcano has been described as extensional, with maximum horizontal shortening in NE-SW and NW-SE directions (Pérez-López et al, 2007) and local compressional stress states (Maestro et al, 2007). Geometrical relationships between the location and orientation of joints and faults indicate two evolutionary phases, implying a counter-clockwise rotation of Deception Island which might be related to regional left-lateral strike-slip movements.…”

Hydrodynamic modelling of Port Foster, Deception Island, Antarctica

“…Port Foster has an almost elliptical shape being 9.8 km long and 5.7 km wide (Smith 2003), with an approximate perimeter of 32 km and a maximum mid-bay depth of c. 160 m (Pérez-López et al . 2007). There is a narrow connection between the inner bay and the sea located at the south-east of the island, known as Neptune’s Bellows, which has a maximum depth of c. 10 m.

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