loading page

GPS Imaging of Mantle Flow-Driven Uplift of the Apennines, Italy
  • William Charles Hammond,
  • Nicola D'Agostino
William Charles Hammond
University of Nevada Reno

Corresponding Author:[email protected]

Author Profile
Nicola D'Agostino
Istituto Nazionale di Geofisica e Vulcanologia
Author Profile

Abstract

We use a newly updated GPS dataset and the GPS Imaging technique to show that the relief of the Apennines Mountain chain in Italy is currently increasing along its entire length by 1-2 mm/yr. We image positive uplift along the entire length of the Apennine crest including the northern Apennines, Calabria and northern Sicily. The maximum uplift rate is aligned with the topographic drainage divide, the greatest elevations and the zone of horizontal extension accommodating east-northeast translation of the Adriatic microplate relative to the Tyrrhenian Basin. Uplift occurs in a 100 - 150 km wide zone with a profile similar to the long wavelength topography, but not to shorter wavelength topography generated by active faulting and erosion. A zone of lower amplitude uplift aligns with the restive volcanic fields and high geothermal potential west of the Apennines, e.g., at Campi Flegrei, Alban Hills, and Monte Amiata-Larderello. Several factors including consistency of the geodetic rate with geologic uplift rates, and incompatibility with transient hydrological or earthquake cycle effects imply that it is a long-lived feature. Uplift occurs despite that the expected consequence of extension is crustal thinning and subsidence, suggesting a causal relationship between gravitational forces and active extension. Anomalies in gravity and upper mantle seismic velocity suggest that elevation gain is driven by forces originating in the mantle. We use these observations to address the hypothesis that these forces result from upward flow of asthenosphere beneath the Apennines, although the spatial and temporal scale of the mantle circulation is unclear.