Tuesday, 28 August 2007
2.PS-60
Active tectonics on Deception Island (West-Antarctica): A new approach using the fractal anisotropy of lineaments, fault slip measurements and the caldera collapse shape
Raúl Pérez-López1, Jorge L. Giner-Robles1, José J. Martínez-Díaz2, Miguel A. Rodríguez-Pascua1, Marta Bejar2, Carlos Paredes3, and José M. González-Casado4. (1) Ciencias Ambientales y Recursos Naturales, Universidad San Pablo CEU, Campus Monteprincipe. Ctra Boadilla del Monte, km 5.600, 28668, Madrid, Spain, (2) Geodinámica Interna, Universidad Complutense, Avda Complutense s/n, Madrid, Spain, (3) Matemática Aplicada y Métodos Informáticos, Universidad Politécnica, C/ Alenza nº 4, Madrid, Spain, (4) Geología, Universidad Autonoma, Campus Cantoblanco, Madrid, Spain
This work shows the caldera boundary of Deception Island (South Shetlands, West Antarctica) from structural and fractal analyses. The strain field is determined from two different analyses: field measurement of faults and by the fractal geometry of the spatial distribution of lineaments. In both cases, the strain field is defined as a regional strike-slip with the maximum shortening (ey) NE-SW trending and a local uniaxial extension with the maximum extension NW-SE trending. The local strain field is controlled by the caldera collapse event, overlapping a fracture pattern to the regional fracture set. The elliptical caldera of Deception Island is determined from geology field map, Quickbird high-resolution satellite image, vent alignment and fissure eruptions located at the inner shoreline of Port Foster (inner bay). This ellipse agrees with the tectonic regime proposed, where the maximum axis NW-SE trending is perpendicular to the regional maximum compression (ey), NE-SW.