Morphologies of deltaic strandplains are the result of multiple sedimentary dynamics interacting with climate,neotectonic and anthropic impacts.They record long-term evolution of coastal areas but also reveal past and...Morphologies of deltaic strandplains are the result of multiple sedimentary dynamics interacting with climate,neotectonic and anthropic impacts.They record long-term evolution of coastal areas but also reveal past and present hazards that can be essential to better predict risks in urbanised deltas.This paper aims to identify the effect of a long-term evolution of the prograded plain of the Tiber Delta in using current ground surface variations and geohistorical data.This study applies GIS(Geographic Information System)tools to LiDAR(Light Detection and Ranging)-derived DEM(Digital Elevation Model)data combined with stratigraphical data,aerial photography interpretation and old maps.The main outcome shows areas of subsidence are primarily located in the central part of the Tiber Delta.Lower heights at the river mouth are due to subsidence and specific lower morphologies associated with fast progradation phases,while similar low heights just north in the area of the international airport of Rome are due to subsidence alone.Subsidence under the airport is associated with the compaction of the silty clay infill of the Late Pleistocene Tiber Valley mostly deposited during the Holocene transgressive period.Only observed in the airport area,the presence of washover fans and the large extent of paleolagoons reveal the kind of risks that are increased by this subsidence.This study demonstrates that the densely urbanised central part of the Tiber Delta faces higher risks of marine submersion and coastal flooding considering ongoing relative sea level change.It also contributes to show the importance to better characterise past coastal morphologies to identify areas prone to subsidence.展开更多
文摘Morphologies of deltaic strandplains are the result of multiple sedimentary dynamics interacting with climate,neotectonic and anthropic impacts.They record long-term evolution of coastal areas but also reveal past and present hazards that can be essential to better predict risks in urbanised deltas.This paper aims to identify the effect of a long-term evolution of the prograded plain of the Tiber Delta in using current ground surface variations and geohistorical data.This study applies GIS(Geographic Information System)tools to LiDAR(Light Detection and Ranging)-derived DEM(Digital Elevation Model)data combined with stratigraphical data,aerial photography interpretation and old maps.The main outcome shows areas of subsidence are primarily located in the central part of the Tiber Delta.Lower heights at the river mouth are due to subsidence and specific lower morphologies associated with fast progradation phases,while similar low heights just north in the area of the international airport of Rome are due to subsidence alone.Subsidence under the airport is associated with the compaction of the silty clay infill of the Late Pleistocene Tiber Valley mostly deposited during the Holocene transgressive period.Only observed in the airport area,the presence of washover fans and the large extent of paleolagoons reveal the kind of risks that are increased by this subsidence.This study demonstrates that the densely urbanised central part of the Tiber Delta faces higher risks of marine submersion and coastal flooding considering ongoing relative sea level change.It also contributes to show the importance to better characterise past coastal morphologies to identify areas prone to subsidence.
