Investigation of pre-1700 Earthquakes Between the Adda and the Middle Adige River Basins (Southern Alps) - Historical Seismology: Interdisciplinary Studies of Past and Recent Earthquakes - page 117

some large stones were also located some metres far from the building. The collapse
layer contained remains of the windows of the “little tower” (Bombonato et al.,
2000). Finally the two walls still in situ showed a corner expulsion (Galadini and
Stucchi, 2007). The archaeological information permitted to relate the destructive
event to the 13th-14th century. The collected data (particularly the corner expulsion
and the “launch” of stones far from the original edifice) can be considered consistent
with the effects of a strong seismic shaking. Bombonato et al. (2000) attributed the
destruction to the 1348 earthquake, that caused severe damage in Friuli, Karnten and
Western Slovenia (Hammerl, 1994) whose epicentre is presently located in Friuli
(CPTI Working Group, 2004).
The effects in Bolzano have been significant. The Bozner Chronik (14th cent.)
report the destruction of ten houses and a tower. In such case the consistency of
the historical and archaeoseismological information is evident. However, the 1348
high damage in Bolzano, located about 150 km east of the epicentral area, is surpris-
ing. This may result from possible site effects in the area: indeed, a small damage
(I 6-7 MCS), not comparable with the destruction depicted by historical and ar-
chaeoseismological data for the 1348 event), affected Bolzano also in 1976 as an
effect of a Mw 6.5 earthquake originated in the same region of the 1348 event.
Alternatively, the 1348 damage in Bolzano may result from a local still undefined
event. In such a case this event might corroborate the hypothesis of a significant,
seismogenic potential of the upper Adige valley region, already suggested by the
Egna archaeoseismological case, consistent with the NNE-SSW alignment of the
seismicity from the southern sector of Lake Garda to the Adige Valley.
3.7 Giudicarie Valley
Similarily to the Insubrian Line, this area represented a concern for many geolo-
gists of the 60's and 70's who hoped, in some way, that seismicity located in the
area might prove that the lineament was active. Actually, an instrumental recording
campaign promoted by the former Istituto per la Geofisica della Litosfera of CNR,
Milano, in 1971 gave practically no results and very little seismicity appeared from
the Postpischl (1985a) catalogue. Then, during the phase of the hunt for the fake
quakes, a couple of moderate events, 1683 Mw 5.0 and 1851, Mw 4.96, located in
the area or just near by, were unearthed by Albini et al. (1994b), following hints by
Tovazzi (1803) and Schorn (1902).
4 Conclusion
Most of the events up to 1700 in the investigated area are still known through sparse
traces; their epicentral location and magnitude show therefore large uncertainties.
The earthquakes of 1117 and 1222 represent an exception with respect to data avail-
ability; however, the aspects discussed above do not help to constrain the parameters
of these events, too. Unfortunately, there is little hope to improve the available traces
with new historical findings.