**4. Volcanological context of the pontine plain region and volcanic hazards**

The most important volcanic threat is the quiescent Alban Hills volcanic complex (**Figures 11** and **12A, B**). New results for the Alban Hills volcano (Roma, Italy), which

#### **Figure 11.**

*Volcanic map of Italy. Distribution of the Plio-Pleistocene volcanic rocks in the Italian peninsula and geological sketch map of the Sacco River valley (i.e., Alban Hills and middle Latin Valley volcanic field associated with the pontine plain). Drawn after Refs. [13, 14]. Main monogenetic volcanoes are represented by cinder cones, tuff rings, and small plateau-like lava flows [15].*

#### **Figure 12.**

*A geological setting of the Colli Albani volcano Central Italy. B three-dimensional view of the Colli Albani volcano (10 times vertical exaggeration). The study sites are located in the west-southwestern sector of the volcano, namely, the Imater quarry, Zolforata di Pomezia mine, Zolforatella, and Laurentina 1–4 outcrops (L1, L2, L3, and L4). Except the Imater quarry (unaltered term), hydrothermal alteration and sulfate or sulfide mineralization affect all other study sites. Alteration occurs at Zolforata di Pomezia and Zolforatella (proximal outcrops), whereas L1 to L4 are distal outcrops. GRA is the main highway encircling the city of Rome [16, 17].*
