Paleoseismological surveys for the identification of capable faults in urban areas: the case of the Mt. Marine Fault (Central Apennines, Italy).

Abstract

In order to constrain the Fault Displacement Hazard (FDH) of the town of Pizzoli, located 10 km NW of L’Aquila (Central Apennines, Italy), we performed two paleoseismological trenches across multiple fault splays within the hanging wall of the main Mt. Marine active normal fault. Our trenches highlighted the presence of five faults arranged both synthetic and antithetic to the main fault. The fault splays are distributed within an across-strike distance of about 500 m. Each fault segment shows evidence of repeated surface-rupturing earthquakes occurring throughout the Late Pleistocene-Holocene, proving their capability of rupturing the surface during recent earthquakes. Our study shows that multiple parallel fault splays belonging to a principal segmented fault are active during the same time interval, although the slip rates of single faults may be different through time. Our work reiterates the importance of performing paleoseismological investigation for assessing FDH in urban areas.