GNGTS 2021 - Atti del 39° Convegno Nazionale

77 GNGTS 2021 S essione 1.1 sediment remobilization both at the lake margins and close to its depocenter. Several hints for sediment reworking by high-energy processes are present, such as coarser grain sizes, relatively large wood fragments, broken gastropods and ostracod remains, as well as displaced macro- phyte-derived carbonate fragments. Two resedimented beds were identified that might represent lacustrine seismo-turbidite de- posits recording two events that have occurred some months apart. In our interpretation, the two sandy layers, topped by detrital carbonate grains, are related to the May 6 and September 15 major earthquakes during the Friuli seismic sequence. The observation of larger thickness of the uppermost Ca-rich layer combined with radiometric dating suggests a more intense sediment input during the most recent seismo-turbidite, in agreement with seismological data suggesting that the September 15, 1976 earthquake was associated with the strongest ground motion in the lake region (Polonia et al ., 2021b). Our results stress the importance of lacustrine environments as efficient recorders of seismic events. References Anderlini, L., Serpelloni, E., Tolomei, C., De Martini, P.M., Pezzo, G., Gualandi, A., Spada, G., 2020. New insights into active tectonics and seismogenic potential of the Italiano Southern Alps from vertical geo- detic velocities . Solid Earth, 11, 1681–1698. https://doi.org/10.5194/se-11-1681-2020. Aoudia A., Saraò A., Bukchin B., Suhadolc P.; 2000: The 1976 Friuli (NE Italy) thrust faulting earthquake: a reappraisal 23 years later . Geophys. Res. Lett., 27, 573-576, 10.1029/1999GL011071. Cheloni, D., D’Agostino, N., D’Anastasio, E., and Selvaggi G., Reassessment of the source of the 1976 Friuli, NE Italy, earthquake sequence from the joint inversion of high-precision levelling and triangulation data . Geophys. J. Int. (2012) 190, 1279–1294 doi: 10.1111/j.1365-246X.2012.05561. Martinis B. and Cavallin A.; 1978: Ground cracks caused by the Friuli earthquake, 1976 from M. Cuarnan and Tremugna valley . In: Proceedings Spec. Meet. on the 1976 Friuli earthquake and the antiseismic design of nuclear installation, CNEN, Roma, 87-102. Moernaut, J.; 2020: Time-dependent recurrence of strong earthquake shaking near plate boundaries: A lake sediment perspective . Earth-Science Reviews, 210, 103344, 10.1016/j.earscirev.2020.103344. Peruzza L., Poli M. E., Rebez A., Renner G., Rogledi S., Slejko D., Zanferrari A.; 2002: The 1976-1977 seismic sequence in Friuli: new seismotectonic aspects . Mem. Soc. Geol. It, 57, 391-400. Poli M. E., Peruzza L., Rebez A., Renner G., Slejko D., Zanferrari A.; 2002: New seismotectonic evidence from the analysis of the 1976-1977 and 1977-1999 seismicity in Friuli (NE Italy) . Boll. Geof. Teor. Appl., 43 (1-2), 53-78. Polonia A., Albertazzi S., Bellucci L. G., Bonetti C., Giorgetti G., Giuliani S., López Correa M., Mayr C., Peruzza L., Stanghellini G., Gasperini L.; 2021a: Decoding a complex record of anthropogenic and natural im- pacts in the Lake of Cavazzo sediments, NE Italy . STOTEN, 10.1016/j.scitotenv.2021.147659. Polonia A., Albertazzi S., Bellucci L. G., Bonetti, C., Bonetti J., Gallerani, A., Giorgetti G., Giuliani, S., Lopez Correa M., Mayr C., Miserocchi S., Peruzza L., Savelli F., Stanghellini G., Gasperini L.; 2021b: Multidisci- plinary dataset for geological and environmental studies in the lake of Cavazzo (Southern Alps) . Submit- ted to Data in Brief. Pondrelli S., Ekström G., Morelli A.; 2001: Seismotectonic re-evaluation of the 1976 Friuli, Italy, seismic sequence . J. Seismol., 5, 73-83, 10.1023/A:1009822018837. Slejko D., Neri G., Orozova I., Renner G., Wyss M.; 1999: Stress field in Friuli (NE Italy) from fault plane solu- tions of activity following the 1976 mainshock . Bull. Seism. Soc. Am. 89, 1037-1052. Zanferrari A., Masetti D., Monegato G., Poli M.E.; 2013: Geological map and explanatory notes of the Italian Geological Map at the scale 1:50,000: Sheet 049 “Gemona del Friuli” . ISPRA - Servizio Geologico d’Italia - R. A. Friuli Venezia Giulia, 262 pp., www.isprambiente.gov.it/Media/carg/friuli.html. Corresponding author: alina.polonia@bo.ismar.cnr.it