Monti Sabatini and Colli Albani: the dormant twin volcanoes at the gates of Rome

Abstract

this multidisciplinary work provides an updated assessment of possible future eruptive scenarios for the city of Rome. Seven new 40 Ar/ 39 Ar 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. The city of Rome was founded upon tuffaceous hills that are part of a thick pyroclastic plateau formed by the eruptions of two large volcanic districts: Monti Sabatini (MS) to the NW and Colli Albani (CA) to the SE (Fig. 1). A number of recent studies has ascertained the state of quiescence of the CA, given an average dormancy of 38.5 ± 1.5 kyr during the last 600 ka, and the occurrence of the most recent eruption at 36 ± 1 ka 1 (and references therein). Moreover, a 20 year-long InSAR data record revealed ongoing inflation with maximum uplift rates >2 mm/yr in the area hosting the most recent (<200 ka) eruptive vents, suggesting that magma recharge is possibly occurring at depth 2 (and references therein). In contrast, no similar studies have been undertaken in the MS so far, precluding a reliable assessment of its actual state. However, a recent geomorphologic study on the fluvial terraces of the Tiber Valley found evidence of ca. 50 m of differential uplift occurred along the MS eastern sector in the last 125 kyr, concurrent with the most recent phase of eruptive activity from multiple vents 1 (Fig. 1). For this reason, a dedicated research project has been conducted to refine the MS eruptive history through a set of new 40 Ar/ 39 Ar age determinations, and to assess possible active soil deformation, including seismotectonic processes and vertical movements, through InSAR analysis. The analysis of the regional seismicity, comparing instrumental and historical records for the four volcanic districts of Latium, is provided aiming at highlighting possible unrest indicators, as recently shown for the CA 2. Geologic setting The MS belongs to the highly potassic Roman Magmatic Province 3 , which originated in the area comprised between the Apennine orogen and the Tyrrhenian ...

Mediterranean tephrostratigraphy and peri-Tyrrhenian explosive activity revaluated in light of the 430-365 ka record from Fucino Basin (central Italy)

“…± 5 ka in the Fucino record, which confirms the 30.6 ± 6.4 kyr-long dormancy preceding the onset of the Villa Senni eruption cycle (365.8 ± 1.4 ka), as previously suggested (Gaeta et al, 2016). Such dormancies have relevance in understanding the relationships between the geodynamic/tectonic and magmatic processes (Marra et al, 2004), stress-field and eruptive activity (Marra et al, 2009), as well as in assessing the volcanic hazard in the Roman area (Marra et al, 2016a(Marra et al, , 2020b. In particular, the Colli Albani volcano is characterized by a quasi-periodic eruptive behaviour, with average recurrence times of 41 ± 2 kyr for the onset of the main eruptive cycles and average dormancies of 38 ± 2 kyr (Marra et al, 2016a).…”

“…In contrast, no relevant activity is documented at Sabatini Volcanic District during the MIS 11 period. Indeed, the intense explosive activity of the Southern Sabatini stage took place between 500 ka ("Fall A" Plinian eruption) and 439 ka ("La Rosta" Plinian fall; Sottili et al, 2004;Marra et al, 2020b), while the subsequent Bracciano stage started at ~325 ka, thus suggesting a long phase of quiescence extending for more than ~100 kyr. However, the recent attribution of CC-2 pumice fall, which is bracketed between Vico α and Vico β, to the Sabatini activity (Pereira et al, 2020), would partially fill this seemingly long gap in activity.…”

“…If confirmed by future investigations, the recognition of this eruption cluster may shed new light on the Sabatini eruption frequency. Indeed, during the whole eruptive history (589 ± 4 ka to 70 ± 3 ka) of the district, the longest dormancy of ~90 kyr has been so far documented in the time span 438 ± 1 to 329 ± 4 ka (Marra et al, 2020b).…”

Conservation of 87Sr/86Sr During Wine-Making of White Wines: A Geochemical Fingerprint of Geographical Provenance and Quality Production

“…Both vineyards lie on the volcanic succession of the Latera volcano in the surrounding of the Pitigliano village. This volcano belongs to the Vulsini Volcanic District, a 1,500 km 2 widespread volcanic area formed in the time span from 591 to 111 kyr BP (Conticelli et al, 1986(Conticelli et al, , 1987(Conticelli et al, , 2010Vezzoli et al, 1987;Turbeville, 1992;Marra et al, 2020a). The volcanism produced a thick sequence of pyroclastic deposits and lava flows, erupted from five main volcanic apparata, namely, the Paleo-Bolsena, the Bolsena, the South-Vulsini, the Montefiascone, and the Latera volcanoes (i.e., Vezzoli et al, 1987;Conticelli et al, 2010;Palladino et al, 2010;Marra et al, 2020b).…”

Active monitoring of residential radon in Rome: a pilot study

“…In its territory, soil outcroppings represent products of both volcanic and exogenous activity. The volcanic district of the Colli Albani (20 km SE of Rome) and that of the Mti Sabatini (NW) determined the deposition of a thick pyroclastic blanket creating a vast plateau 6 . The eruptions of the Colli Albani volcanic complex, in particular, have led to the placement of numerous and extensive pyroclastic formations which as a whole cover most of the territory of the Municipality of Rome and which develop mostly in the east and south of the city 7 .…”