EARTHQUAKE MOLISE – ITALY

On 16 August an earthquake of Mw 5.1 occurred 4 km SE of the village of Montecilfone (Molise, southern Italy); up to 20 August about 200 aftershocks, including 9 up to Mw 3, (Fig.1) were recorded by the Italian national accelerometric network (RAN) and by some temporary stations installed by the National Institute of Geophysics and Volcanology (INGV). The epicentral area corresponds to the hilly landscape between the Biferno and Trigno Rivers where a complex sedimentary succession of terrigenous deposits outcrops, including scaly clays ascribable to the Argille Varicolori Formation of the Paleocene, pelitic-arenaceous flysch of the Miocene-Pliocene and Pliocene silty clays (Fig.2).
Immediately after the earthquake the research center “Sapienza” of CERI in collaboration with the local geological office Geoservizi S.r.l. conducted field surveys for the inventory of soil effects induced by the earthquake. These surveys were carried out as soon as possible, to avoid the possible deletion of the ground evidence due to further rains and interventions by local farmers.
No effects induced by the earthquake have been documented so far in this area (between Guglionesi, Larino and Montenero di Bisaccia) according to CEDIT and CFTI5 catalogues. Therefore, this is the first time that in this sector of the Central Apennines it is possible to inventory the effects induced by the earthquake and to analyze their spatial distribution.
Up to now, some tens of landslides induced by the earthquake have been inventoried, concentrated in a radius of almost 2 km from the epicenter. These landslides consist mainly of earth slide reactivations (Fig.3); for many of them, the locals testified that the movement occurred as a result of the mainshock. Reactivation of landslides caused, in some cases, non-negligible damage to roads (Fig.4, 5, 6).

The inventoried terrestrial effects will soon be included in the on-line CEDIT catalog managed by CERI “Sapienza”.