Large earthquakes along slow converging plate margins:Calabrian Arc paleoseismicity based on the submarine turbidite record  

作　　者：A.Polonia R.Melis P.Galli E.Colizza D.D.Insinga L.Gasperini 

机构地区：[1]Istituto di Scienze Marine(ISMAR-CNR),Consiglio Nazionale delle Ricerche,Area della Ricerca di Bologna,Italy [2]Dipartimento di Matematica e Geoscienze,Universitàdegli Studi di Trieste,Italy [3]Presidenza del Consiglio dei Ministri,Dipartimento della Protezione Civile,Servizio Rischio Sismico-Roma,Italy

出　　处：《Geoscience Frontiers》2023年第5期241-266,共26页地学前缘（英文版）

摘　　要：The Calabrian Arc subduction-rollback system hosts seismogenic faults capable of generating earthquakes exceeding magnitude 7.Since earthquakes are the result of long-term geodynamic processes,documenting seismic activity during a sufficiently long time interval is of fundamental importance for hazard scenarios.Instrumental and historical data provide critical information on seismogenesis,but they cover time periods shorter than the recurrence times of large earthquakes,especially in areas with low deformation rates such as Calabria.If onshore paleoseismological studies are fundamental to compile earthquake catalogs,they are sometime affected by the relatively poor continuity of sedimentation in the subaerial environment.In this study we applied the paleoseismological approach to the submarine environment to reconstruct the record of high-energy sedimentary events triggered by seismic activity.We analyzed three gravity cores collected in disconnected sedimentary basins to reconstruct resedimentation processes during the Holocene,integrating inland information for a better assessment of tectonic activity and seismogenesis.Multiproxy analyses of the sedimentary record constrained by radiometric dating allowed reconstructing event stratigraphy and linking resedimented deposits to specific earthquakes.Onshore and offshore data allow to identify large-magnitude earthquakes in the central Calabrian Arc subduction system during the Holocene,with inferred epicenters located either along normal faults onshore and/or related to the slab dynamics.The turbidite record reveals 20 major events during the last 10 ka,with sources including crustal faults in Calabria(i.e.Lakes,Rossano and Cittanova faults).Analyses of sediment samples and high-resolution seismic reflection images allowed identification of different types of resedimented deposits during the last 30–50 ka.The basin-wide occurrence of three megaturbidites/homogenites suggests they are related to megatsunamis sourced by far field earthquakes along the Hellenic Arc.

关 键 词：Calabrian Arc Earthquakes Seismic shaking Sedimentation Seismo-turbidites 

分 类 号：P588.3[天文地球—岩石学]