CONDIZIONI GEOMORFOLOGICHE E STABILITA’ DELL’ACROPOLI DI TARQUINIA VECCHIA

Abstract

C. Cattuto, L. Gregori, M. Milano & S. Rapicetta, Geomorphologic conditions and stability of the Acropoli “Tarquinia vecchia”. (IT ISSN 0394-3356, 2007).
In this paper a study about lithologic and geomorphologic characteristics of the archaeological area of Tarcxuna, the ancient Tarquinia
city, in the Viterbo district (Lazio Region, central Italy) is presented.
The above mentioned archaeological area is situated on the sub-horizontal top of a hill, and it is limited by a high limestone escarpment.
In this area, the Acropoli, many archaeological objects have been recovered, among them the famous terracotta named "Cavalli alati"
that comes from the front of the Temple.
The lithostratigraphical sequence comprises of a high pile of “Argille Azzurre”, of the low-medium Pliocene, then there are two formations of medium-top Pliocene, in lateral facies eteropy: “Calcare di Tarquinia”, limestone of 30 meters of maximum height, and the “Sabbie Gialle”.
The “Calcare di Tarquinia” (famous also as Macco) has a sub-horizontal order and it constitutes the base on which a great part of the
Acropoli of “Tarquinia Vecchia” rises and the limestone escarpment that limits the archaeological area too.
The limestone is fractured-karst rock and the waters that cross it constitute aquifers that fill small sources at contact with the “Argille
Azzurre”.
The clay slides and so remove the support to the limestone escarpment that collapse in blocks also large dimensions.
The regression of the escarpment is favoured by the agricultural activity, that is realized carried out until the base of the escarpment.
The above mentioned regression affect the “Argille Gialle” that are over, therefore in more points, there are landslides that induce the
collapse of some areas of the Tarquinia Vecchia town-walls.
In order to mitigate the landslide risk in the archaeological area, it is necessary: to stop the rill erosion, to reduce the infiltration, to capture and to remove the waters emerging at the base of the limestone escarpment, to create structures able to control and to support the base of the escarpment.