Publication Date:
2018-07-12
Description:
We report on a high-resolution, low-altitude aeromagnetic investigation of the central
Apennine extensional seismogenic zone, hit by destructive historical earthquakes including the 2009
L’Aquila seismic sequence. Central Apennines are predominantly made by thick (〉4 and possibly up to
12 km) packages of shelf and deep marine limestones and dolomites of Mesozoic age, unconformably
covered by upper Pliocene-Holocene continental sediments lying on (often active) normal fault hanging
walls. Seismogenic faults cut the carbonates down to 10- to 12-km depth, where the brittle-ductile
transition occurs. Aeromagnetic data were collected during June 2014 with a cesium magnetometer, along
200-m-spaced flight lines. Apart from a regional 80-nT anomaly that we modeled at 30- to 40-km depths
in the lower crust of the Adria plate, weak magnetic residuals are observed. As expected, normal faults
cutting the diamagnetic carbonates lack any magnetic fingerprint. However, shallow continental basins
yield clear anomalies of 2- to 8-nT intensity, as they contain both residual soils and tephra erupted after
0.7 Ma by volcanoes from the Tyrrhenian margin of Italy. Basin margins imaged by aeromagnetism
mirror the geometry of their causative normal faults. Thus, aeromagnetic residuals document many of the
central Apennine normal faults that were active during the last ~3 Ma. Most prominent anomalies reflect
basins formed after 0.7 Ma, as their magnetization is significantly higher than that of older continental
basins. We conclude that rectilinear boundaries of most prominent anomalies reflect faults formed after
0.7 Ma, thus probably seismogenic.
Description:
Published
Description:
1435-1453
Description:
1A. Geomagnetismo e Paleomagnetismo
Description:
JCR Journal
Keywords:
Magnetic anomalies
;
Central Apennine
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink
