Recent uplift of the Alban Hills Volcano (Italy): Evidence for magmatic inflation?

Abstract

First‐order leveling surveyed in 1951 and 1994 along a line across the Alban Hills volcano reveals maximum vertical uplift of 30 cm (average of 7 mm/yr) in the region of geologically recent (0.020–0.030 Ma) explosive activity. The uplifted region corresponds to an area where seismic activity is concentrated, at depths of 3–6 km. Uplift exceeding 10 cm is observed over a 14‐km wide zone in the center of a 40‐km long line, with the deformation tapering to zero at both ends of the line. Data from a few sparse, older benchmarks measured in 1891 and 1927 suggest that the deformation in the first half of this century was very small compared to the period 1951–1994. The observed uplift, together with increased seismic activity, suggest that recent magma injection has occurred in the upper crust beneath the Alban Hills volcano.