Page 403 - Caldera Volcanism Analysis, Modelling and Response

378 Claudia Troise et al.

Figure 2 (a) Sketch of vertical movements history at Macellum in Pozzuoli, known as
SerapisTemple (after Bellucci et al., 2006). Black circles represent the constraints found from
radiocarbon and archeological measurements by Morhange et al. (1999); white circles
(post-1538) represent inference from Dvorak and Mastrolorenzo (1991);(b) Verticalground
displacements as recorded at the benchmark in Pozzuoli harbor by leveling data in the period
1969--2006 (Macedonio andTammaro, 2005; Del Gaudio et al., 2005; Pingue et al., 2006).

This paper analyzes precise leveling and GPS data in the area from mid-2004 to
October 2006, and shows that a new episode of uplift has started in the area with an
apparent rate lower than the previous mini-uplift episodes (almost 4 cm in the last
year, compared to the 0.5–1.5 cm/month of the previous episodes since 1989). The
similarity of the present long-term uplift episode, lasting since 1969, with past
events, and in particular that which culminated in the 1538 eruption, makes it
particularly important to study in detail any resuming of uplift. As hypothesized in
the most recent literature (De Natale et al., 2001, 2006; Battaglia et al., 2006;
Bellucci et al., 2006), eruptions at this and similar calderas can occur suddenly in the
initial part of new uplift phases. This paper then tries to discriminate the source
of the present uplift phase, in terms of the identification of a new magmatic
and/or geothermal perturbation, and to highlight its consequence on eruption hazard
assessment. We show that data from this episode help to discriminate the nature of
uplift episodes and to establish their connections with magmatic phenomena.