RESUMO
This multi-disciplinary work provides an updated assessment of possible future eruptive scenarios for the city of Rome. Seven new 40Ar/39Ar ages from selected products of the Monti Sabatini and Vulsini volcanic districts, along with a compilation of all the literature ages on the Colli Albani and Vico products, are used to reconstruct and compare the eruptive histories of the Monti Sabatini and Colli Albani over the last 900 ka, in order to define their present state of activity. Petrographic analyses of the dated units characterize the crystal cargo, and Advanced-InSAR analysis highlights active deformation in the MS. We also review the historical and instrumental seismicity affecting this region. Based on the chronology of the most recent phases and the time elapsed between the last eruptions, we conclude that the waning/extinguishment of eruptive activity shifted progressively from NW to SE, from northern Latium toward the Neapolitan area, crossing the city of Rome. Although Monti Sabatini is unaffected by the unrest indicators presently occurring at the Colli Albani, it should be regarded as a dormant volcanic district, as the time of 70 kyr elapsed since the last eruption is of the same order of the longest dormancies occurred in the past.
RESUMO
The ciy of Rome is subjected to moderate seismic risk due to both local and external seismicity. Up to now, the maximum intensity felt has never exceeded VIII MCS. The 1 November 1985 (Io = VII) and 31 August 1909 (Io = VI) earthquakes demonstrate that small local events can also cause damage in a large old city. In the present work, we have re-evaluated the intensity values of those two events by means of automatic processing. A comparison between the present results with geological evidence and previous studies is shown, especially for the historical centre of Rome. For the first time, the 1909 earthquake instrumental magnitude Ml=3.6 has been calculated from original recordings.(AU)