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settlement, instability of the Adige river flank or liquefaction. The main limit of the
hypothesis of surface faulting affecting the ancient building was represented by the
impossibility to detect the prolongation of the shear planes towards both north and
south.
Indeed, the archaeological site was completely surrounded by the modern build-
ings within the Egna village. The analysis of the aerial photographs preceding the
modern development of the village did not permit to identify geomorphological
traces of recent displacements (e.g. fault scarps). This was probably due to the
significant alluvial deposition subsequent to the displacement of Roman age, re-
sponsible for sealing the displacement (Galadini and Galli, 1999). Considering the
difficulty of the tectonic analysis, the archaeoseismological case of Egna was ap-
proached from a “territorial” point of view, i.e. through the review of the archaeo-
logical information derived from the literature on other archaeological excavations
of the Trentino-Sudtirol region. The information gathered in Galadini and Galli
(1999) defined a period of significant changes to edifices and villages (destruction,
abandonment, restoration or rebuilding) during the 3rd century. For example, the ex-
cavation at the Teatro Sociale in Trento uncovered numerous structures dated at the
3rd century AD, sealing older remains (Zamboni, 1989, pers. comm.). This period
of important change is traditionally attributed to the instability related to the Alaman
invasions of northern Italy, since 258 AD (Christlein, 1979; Buchi, 2000; Ciurletti,
2002). Data published more recently and related to the northernmost sectors of the
investigated area (Tesido, close to Monguelfo-Welsberg and San Candido-Innichen;
Di Stefano and Pezzo, 2002; Dal Ri et al., 2002, respectively) define changes to the
pre-existing edifices in the second half of the 3rd century AD. Therefore, this im-
portant period of interventions to the Roman buildings seems to be related to a very
large territory. This area may be larger than that potentially affected by coseismic
damage due to an event approximately located in the Egna area, also in case of a
large magnitude event. In conclusion, on one side the archaeological information
suggests the occurrence of a destructive seismic event at the border between the
Trento and Bolzano provinces, in the half of the 3rd century AD, on the other side
the full comprehension of this event is hindered by the local instabilities related to
invasions.
3.6.3 Bolzano: Archaeoseismological Evidence
Archaeological excavations in the cloister of the Capuchin Convent in Bolzano un-
covered remains of a tower bearing traces of collapse and damage. This edifice was
defined as the “little tower” of the Wendelstein Castle (property of the Earls of Tyrol)
by Bombonato et al. (2000). The building of this tower, based on the comparison
with the style of other towers of the zone, has been attributed to the first half of
the 13th century. Two angular walls, pertaining to an edifice having a quadrangular
geometry in plan view, each side being 5.5 m long, were uncovered. The walls were
made by stones with irregular forms and size, linked by mortar. The walls were about
0.9 m thick. The collapsed materials (including remains of the upper floors) filled the
building. A thick collapse layer buried the entire area of the archaeological site and
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