Actividad de una falla asociada a la erupción volcánica de la Isla Decepción en 1970 (Antártida Occidental):la Falla de María
- Raúl Pérez-López 1
- Míguel Ángel Rodríguez Pascua 2
- M. Béjar 3
- José Jesús Martínez Díaz 3
- Jorge Luis Giner Robles 1
- P.G. Silva 4
- Pilar Villamor Pérez 5
- José Manuel González Casado 6
- 1 Dpto. CC. AA. y RR. NN. Universidad San Pablo.
- 2 Área de Riesgos Geológicos. Instituto Geológico y Minero de España
- 3 Dpto. de Geodinámica. Facultad de CC. Geológicas. Universidad Complutense de Madrid.
- 4 Dpto. de Geología. Universidad de Salamanca.
- 5 Dpto. of Paleoseismicity and Volcanology
- 6 Dpto. de Geología y Geoquímica. Facultad de Ciencias. Universidad Autónoma de Madrid
ISSN: 1576-5172
Year of publication: 2008
Issue Title: VII Congreso Geológico de España
Issue: 10
Pages: 1043-1046
Type: Article
More publications in: Geotemas (Madrid)
Abstract
This work addresses the presence of a superficial rupture fault scarp in relationship with the phreatomagmatic eruption occurred in 1970 at Deception Island, West Antarctica. We have analysed aerial photographs (1968) previous to the eruption and contemporaneous high resolution satellite image (Quickbird, 2003). This information was relevant to establish the scarp morphology, fluvial network variations and uplifted fluvial terraces. Accordingly and during the austral summer of 2007, we carried out a field survey with the purpose to perform several paleoseismic trenches across the fault scarp. This analysis showed a reverse fault movement through 1 km of superficial rupture with 20 cm of vertical throw. This activity affected to the pyroclastic volcano sedimentary sequence of the 1970’s eruption. We propose three models that could explain this activity: (1) Reverse small-moderate earthquake (5 M 6) triggered by the 1970`s eruption, (2) Reactivation of a previous fault as a consequence of dike injection and/or magma migration in relationship with the eruptive process and (3) Aseismic fault creep activity post-earthquake.