Characterization and 3D reconstruction of a transtensional fault system by means of the comparative analysis of field work and geophysical investigations: the case of the Mola plain (Elba Island, Italy)

Ivan Callegari (a), Filippo Bonciani (a), Enrico Guastaldi (a), Tommaso Colonna (a), Giovanni Liali (a) & Giovanni Massa (a)
(a) CGT Center for GeoTechnologies, University of Siena, Via Vetri Vecchi, 34 - 52027 San Giovanni Valdarno, Arezzo, Italy.

Nowadays several research projects concern the research of drinking water, which is a fundamental need in coastal areas and small islands, such as Elba Island (Tuscan archipelago, in the northern part of the Tyrrhenian Sea), and study of greater exploitation of existent aquifers. One of them is the fractured aquifer of Mola coastal plain (“Piana di Mola”, SE of the Elba Island, Italy). This study is focused on the reconstruction of a brittle structural model of this area, by means of field work, geophysical data and 3D modeling, in order to synthesize the rock mass fracturing systems conditioning the groundwater flow. This model highlighted a regional system of brittle deformation correlated to recent tectonic movements, which played a fundamental role in the actual geological structure of Elba Island. From the comparative analysis of new geological field data and geophysical investigation we recognized a left transtensional fault system with negative or normal flower structure, with a vertical throw increasing from east to west. This multidisciplinary study points out new elements and insights for understanding the recent evolution of the tectonics of northern Tyrrhenian sea upper brittle crust.

3D modeling, brittle structure, Elba geology