Volcanological and structural evolution of the Ischia resurgent caldera (Italy) over the past 10 k.y.

Abstract

Volcanic activity on the island of Ischia in the past 10 k.y. has included both effusive and explosive eruptions, mainly in the eastern sector of the island. Vent location, eruption dynamics, transport mechanisms, and depositional processes have been reconstructed for each recognized lithostratigraphic unit. Periods of quiescence have alternated with periods of very intense volcanism, mainly concentrated at ca. 5.5 ka and over the past 2.9 k.y. Volcanism has not been continuous, but it has been strongly infl uenced by the mechanism of a resurgence phenomenon that has affected the island since ca. 33 ka. Therefore, it has been hypothesized that magma intrusion and uplift events have occurred intermittently. In the past 5.5 k.y., volcanic activity has been invariably accompanied by the emplacement of slope instability–related deposits, illustrating that the slope instability was also induced by reactivation of vertical movements, likely related to resurgence.