Identifying fossil fault activity along the eastern Periadriatic Fault system by means of combined luminescence- and ESR-dating of fault gouges (NE Italy, S Austria and N Slovenia)
We intend to investigate the eastern Periadriatic Fault system at the transition from the Eastern to the Southern Alps by means of combined optically stimulated luminescence (OSL) of feldspar and electron spin resonance (ESR) dating of quartz from fault gouges. The Periadriatic Fault (PAF) system can be traced along-strike the entire Alps and is one of its tectonically and geomorphologically most important features. It has accommodated between 150 and 300 km right lateral strike-slip motion between the European and the Adriatic plates since about 35 Ma. The eastern PAF system reveals relatively little instrumental seismic activity, particularly when compared to the southerly adjacent Southern Alps and northern Dinarides in Friuli and northwestern Slovenia. However, it has likely hosted strong historical earthquakes, such as the Mw 7.1 event in 1348 and the Mw 6.5 event in 1690, with epicentres in Carinthia (southern Austria). GPS data suggest that the eastern PAF system still accommodates parts of the Adria-Europe convergence. Building on the fact that the intensity of the OSL and ESR signals in quartz and feldspar can become partially reset by frictional heating during seismogenic faulting, we intend to better constrain the timing of past seismic events by investigating natural fault gouges along the eastern PAF system. This approach will help to unravel which of these faults have been seismically active throughout the Quaternary.