A large unknown historical earthquake in the Abruzzi region (Central Italy): combination of geological and historical data

The combination of paleoseismological and historical investigation can be used to obtain a complete knowledge
of past earthquakes. In Italy the 1000 year-long record of historical earthquakes provides an opportunity
to compare data from the catalogue with results from paleoseismologic investigations. Trenching results along
the Ovindoli-Pezza Fault (OPF). in the Abruzzi region. showed two surface faulting events. The most recent of
these events occurred after 1019 A.D. and should be reported in the Catalogue of Italian Seismicity. Nevertheless,
the earthquake appears to be missed or not well located in the Catalogue. In order to define in which century
a large earthquake on the OPF should have clearly left a sign in the historical record, we carried out historical
investigations back to the XI century. The studies were mainly focu5ed on disclosing possible <<negative>>
e vidence for the occurrence of the most recent event along the OPF. No clear records related to this
event were found but on the basis of the information we obtained the occurrence of this earthquake can be
constrained between 1019 A.D. and the XV century. possibly between 1019 A.D. and XIII century.