Climate change in the Mediterranean region is evidenced by an increase in average air temperature... more Climate change in the Mediterranean region is evidenced by an increase in average air temperature and a variation in rainfall regime: the value of cumulated annual rainfall seems to be basically constant, however, rainfall of maximum intensity and short duration, between 1 and 24 hours, is increasing, especially in the period between late summer and early autumn. The associated ground effects in urban areas consist of flash floods and pluvial floods, often in very small areas, depending on the physical-geographical layout of the region. In the context of global warming, it follows that it is important to have an adequate monitoring network for these rain events, which are highly concentrated in space and time. This research analyzes the meteo-hydrological features of August 27 th and 28 th 2023 event that occurred in Genoa, just 4 days after the record maximum air temperature recorded: between 19UTC and 02UTC nearly 400 mm of rainfall was recorded in the eastern sector of Genoa's historic center, with significant ground effects such as flooding and overflowing in pressurized culverted waterways. Rainfall observations and estimates were taken using both official or "authoritative" networks (rain gauges and meteorological radar) as well as rain gauge networks inspired by citizen science principles. The combined analysis of the observations by authoritative and "citizen science" networks highlights, for the analyzed event, a spatial variability of the precipitation field for the hourly and sub-hourly duration, which cannot be captured by the current spatial density of the authoritative measurement stations (which it is also among the highest in Italy). Monthly total rainfalls and maximum intensity and short duration annual maxima time series recorded by the authoritative rain gauge network of the Genoa area are then analyzed. Results show that at distances even less than 2 km the variations in average rainfall depth cumulated over sub-hourly duration are very significant. Thus, extreme weather monitoring activity is confirmed as one of the most important aspects in terms of flood prevention and protection in urban areas. The integration between authoritative and citizen science networks can prove to be a valid contribution for monitoring this type of extreme events.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
<p>Liguria region is historically affected by severe hydro-meteorological events of... more <p>Liguria region is historically affected by severe hydro-meteorological events often resulting in dramatic death tolls and large socio-economic impacts. On 7-8 October 1970, Genoa, region capital city, was struck by the most catastrophic flood event of its history. On the evening of 7 October pre-frontal storms affected the western side of the city (Voltri, Prà and Pegli municipalities), while on 8 October 1970 an anticyclone block generated recurring convective systems that hit Genoa city and above all the Bisagno Valley. The heavy rainfall continued more than 24 h with highs at Bolzaneto rain gauge (Polcevera Valley, northwest of Genoa city center) where over 950 mm of rainfall in 24 hours was measured. Over the city center and the Bisagno Valley, 400 mm in 24 h was recorded. The Bisagno stream channels overflowed, submerging the city center. The 1970 event in Genoa City was also the most dramatic in terms of damage: 44 fatalities occurred and over 2000 individuals were evacuated.</p> <p>This study hindcasts the meteorological evolution of this event at high spatial resolution (1.5 km) and temporal one (1 hour) using the Weather and Research Forecasting (WRF) model by downscaling the ERA5 climatology developed by European Center for Medium-Range Weather Forecast (ECMWF). The weather hindcast scenario is compared with available meteorological observations as well as with recorded geomorphological impacts on Genoa city center and municipalities.</p>
Rapallo, with 30,000 inhabitants, is an important seaside tourist resort in the Eastern ligurian ... more Rapallo, with 30,000 inhabitants, is an important seaside tourist resort in the Eastern ligurian coast. It is internationally known since the beginning of the 20th century for elite tourism. Following the development of mass tourism, above all during 1960s and 1970s, the whole municipality has been affected by an intense urbanization \u2013 mainly due to construction of homes for holiday \u2013 which have strongly modified either the former landforms of the flood plain, either the surrounding slopes up to 150-200 m a.s.l. The area covered by urbanization has increased from approximately 45 ha in the early twentieth century, up to 175 ha in 1957, 600 ha in 1978 and 650 ha nowadays. This research is aimed to reconstruct the morphological transformations in a coastal environment, considering the historical changes due to human interventions and the related impact on geomorphological processes occurred since the 18th century. The study is based on field survey and on the interpretation and comparison among ancient and recent maps, aerial stereographic photos and orthophotos, on historic archive data, on drill analysis by several geotechnical investigations conducted on coastal-flood plain for civil and environmental purposes
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The complexity and non-linearity of the morphogenetic system which is responsible for shaping the... more The complexity and non-linearity of the morphogenetic system which is responsible for shaping the Earth's surface have been widely recognised by many authors who have documented the fractal nature of erosion. In this paper, two peculiar kinds of landforms are compared to point out ordered structures, i.e. triangular facets that arise in different geomorphic systems, due to the principle of morphologic convergence. Occurrence of triangular facets has been documented in mountainous areas in relation to base level changes and hydrographical network evolution; similarly shaped landforms are present even in recent tectonic uplift areas along faults. The spatial distribution of the two kinds of facets has been investigated in two river basins located in Liguria (northern Italy) and in a mountainous area in Oman. The results of this analysis document the different spatial features of the two kinds of facets.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Anthropogenic modifications at catchments scale may be reconducted primarily at soil sealing and ... more Anthropogenic modifications at catchments scale may be reconducted primarily at soil sealing and streams culverting, even if important consequences result from roads density and, more in general, infrastructures as they cause landscape fragmentation, and agricultural areas extension. Their most important outcomes in terms of hydrologic balance are the decreasing time of concentration and the increasing flood risk at catchment scale. The research introduces a methodological approach to classify the degree of anthropogenic modifications at catchment scale: clustering techniques have been applied to 508 catchments in a high-risk flooding sector of the Mediterranean region. Then, flood data recorded in the study area in the 1900-2018 period have been compared to clustering classification, pointing out the relationships with soil sealing and hydrographical network culverting in the catchment. The analysis has been performed considering fourteen subsets of 8 descriptive parameters each that differ in the evaluation of culverting in the terminal part of the hydrographical network; the analysis has been conducted identifying the optimal number of descriptive parameters and the corresponding best number of clusters on quantitative basis. The results show that three classes clustering is the more appropriate from a computational point of view. That division looks coherent with the features of the studied basins and is well correlated with floods occurrence in the last 100Â years. Finally, the proposed methodology of anthropogenic disturbance classification at catchment scale may be applied to other areas even adapting and implementing other descriptive parameters. Then, it may be used to support the planning of mitigation strategies in term of flood risk.
We present our research on the Prato Casarile landslide dam in Genoa city to illustrate the inter... more We present our research on the Prato Casarile landslide dam in Genoa city to illustrate the interactions between slope instability processes and structural stabilization interventions aimed to reduce the hazard in a densely-populated area. Analysis of the degradation of structural interventions constructed after flood events in 1953, 1970 and 2014 contributed to an improved mitigation strategy.. At the same time the slope instability processes intensively advanced, and regressive erosion quickly proceeded to the landslide dam threshold. The discontinuity in human interactions in a geomorphic system, after the initial hazard reduction, resulted in an increased threat that combined with a rise in vulnerability due to urbanization expansion. The research findings underline the necessity of constantly assessing the geomorphic evolution and active processes involved in order to determine the specific actions and interventions required to ensure the stability of the landslide dam. Finally, and more generally, we illustrated that anthropogenic interaction in the geomorphic system, specifically when finalized for hazard mitigation, needs to be continuously performed through both the monitoring and maintenance operation phases of the artificial structures.
This paper describes the anthropogenic landforms of the alluvial-coastal plain of Rapallo (Easter... more This paper describes the anthropogenic landforms of the alluvial-coastal plain of Rapallo (Eastern Liguria, NW Italy). Since the second half of the nineteenth-century Rapallo experienced a progressive urban sprawl that became particularly intense after the Second World War and severely modified the former landforms. The identification and mapping of morphological changes was performed through a multi-temporal comparison of historical and recent maps and aerial photographs, an analysis of geo-thematic maps and urban planning documents, an interpretation of stratigraphic data from boreholes, and a field survey activity. The main anthropogenic interventions that shaped the urban landscape of Rapallo were riverbed diversions and channelization, excavations, fillings, and embankments construction along the shoreline. These elements highlight the relevant extent of the human imprint on the pristine environment. Furthermore, the identified anthropogenic geomorphological features, combined with the local physiographic and climatic features, increased flood and sea storm hazards and risks.
Rendiconti online Società Geologica Italiana, Nov 1, 2016
After more than 25 years since the first studies, the Landscape Master Plan of Liguria has contri... more After more than 25 years since the first studies, the Landscape Master Plan of Liguria has contributed to maintaining the cultural and natural landscape. The current plan is made by three descriptive layouts and related regulations: the settlement and botanical settings represent the features of the landscape linked to buildings and vegetation. The geomorphological layout shows only the regulations, without any reference to Earth surface processes and landforms. This research suggests a methodology aiming at providing the plan with an engineering geologic suitable layout with the other settings. We propose eight geomorphological landscape units: all of them are connected with Earth surface dynamic factors, including man-made landforms and geodiversity values. A double key to the interpretation of this geo-map is suggested. The capital letters corresponding to regulations are maintained; we have inserted a new label linked to the geomorphological landscape unit. This updating may be integrated in the review processes of the Landscape Master Plan already started by Regional Authority.
This work presents the geomorphological features associated with the anthropic morphogenesis of t... more This work presents the geomorphological features associated with the anthropic morphogenesis of the Bisagno Stream catchment, combined with the geo-hydrological hazards associated with landslides and floods. This catchment is internationally known for its recurring high-magnitude floods and its geo-hydrological hazards associated with the large and widespread presence of elements exposed at risks. It experienced severe morphological changes due to anthropogenic interventions related to urban sprawl and agriculture. Anthropogenic modifications to the former landscape have been particularly widespread and pervasive over the coastline, the floodplain, and the slopes. They include a general alteration of the pristine landforms, excavation and landfill forms, channelization and culvert of riverbeds, and terraced slopes. The 1:20,000 scale map allows to assess the relationships existing among structures and infrastructures, anthropogenic landforms, and landslides and flood-prone areas. Thus, this tool provides relevant information for land-use planning and land management, in particular under the perspective of geo-hydrological hazards mitigation.
The impacts of climate change are becoming more widespread across the world, with hydro-meteorolo... more The impacts of climate change are becoming more widespread across the world, with hydro-meteorological extreme events on the rise, causing severe threats to nature and communities. Increasing trends in the frequency and intensity of floods and landslides have been projected by climate models. This necessitates the development of more effective measures such as nature-based solutions (NBS) which can complement grey infrastructures. Recent studies have identified knowledge gaps and limitations in existing research and tools that aid in spatial planning for the implementation of large-scale NBS and proposed new methodologies for the spatial allocation of large-scale NBS for flood risk reduction. This work presents a novel method for mapping the suitability of NBS addressing geo-hydrological hazards such as shallow landslides, debris flow, and rockfall, which are typically caused due to slope instability. This methodology incorporates landslide susceptibility mapping, and was used to cr...
9th International conference on Geomorphology, 2017
The Ligurian slopes facing the Tyrrenian Sea extend along the coast for nearly 300 km between Fra... more The Ligurian slopes facing the Tyrrenian Sea extend along the coast for nearly 300 km between France border to Tuscany: this stretch of territory presents more than a hundred catchments characterized by small floodplains. The slopes are very steep, while the alluvial plains are typically narrow and elongated. Ligurian catchments, except for the Roja and the Magra rivers, have common features: they can be distinguished in very small (<15 km2), small (15-150 km2) and medium basins (150-500 km2). Ligurian alluvial plains are historically characterized by floods that have caused damage for million of euro and tens of casualties. Over the last decades, an increase in alluvial events has been observed, both due to the variation in rainfall regime and in changes of land-use, which have heavily influenced the geomorphological processes. The great part of Ligurian urbanized areas are located in floodplains: these large areas represent the expansion of the small historical settlements and their original road connections. Through a comparison of old maps it was rebuilt the morphological evolution of Ligurian floodplains in historical times. Using historical maps of XVIII and XIX century, and regional maps for second half of XX century, the land-use and riverbed changes in the last centuries have been evidenced. The current status was assessed by Google Earth Pro platform. The secular human activities in Liguria have clearly modified the floodplain environment. The main channel, and even the minor hydrographic network, have showed major transformations over time. In many cases a narrowing and riverbed covering has been detected, especially in the medium-terminal stretch, with the aim to create new urbanizable areas for buildings and roads. Other widespread changes finally concern deviations and displacements of the riverbed, progradation of the coastline due to fill
In mountainous areas during intese rain events shallow landslides are often triggered adding thei... more In mountainous areas during intese rain events shallow landslides are often triggered adding their effect and enhancing the damaging consequences of flash flood. Many coastal area of the Mediterranean are exposed to such events, as recently largely happened in Italy, France, Spain and Greek. Large portions of the coastline mountainous territories have been settled and modified since ancient times with agricultural terraces, in order to practice the subsitence cultivation. This kind of anthropogenic modification of the slopes may be considered as an artificial immobilization of debris cover along steep slopes and, particularly after their abandonment, they can turn into sources of shallow landslides. Then terraces from belonging to soil and water conservation measures may represent a source of hazard if not properly mainteined. Considering the intense rain event that hit the Portofino promontory in 1915 causing strong damage to the Medieval monk Abbey in the iconic small San Fruttuoso village in northern Italy, a numerical modeling has been applied basing on historical testifying and the available evidences. A possible terraced area has been highlighted as a source area for the debris/mud flow that hit the Abbey and
Climate change in the Mediterranean region is evidenced by an increase in average air temperature... more Climate change in the Mediterranean region is evidenced by an increase in average air temperature and a variation in rainfall regime: the value of cumulated annual rainfall seems to be basically constant, however, rainfall of maximum intensity and short duration, between 1 and 24 hours, is increasing, especially in the period between late summer and early autumn. The associated ground effects in urban areas consist of flash floods and pluvial floods, often in very small areas, depending on the physical-geographical layout of the region. In the context of global warming, it follows that it is important to have an adequate monitoring network for these rain events, which are highly concentrated in space and time. This research analyzes the meteo-hydrological features of August 27 th and 28 th 2023 event that occurred in Genoa, just 4 days after the record maximum air temperature recorded: between 19UTC and 02UTC nearly 400 mm of rainfall was recorded in the eastern sector of Genoa's historic center, with significant ground effects such as flooding and overflowing in pressurized culverted waterways. Rainfall observations and estimates were taken using both official or "authoritative" networks (rain gauges and meteorological radar) as well as rain gauge networks inspired by citizen science principles. The combined analysis of the observations by authoritative and "citizen science" networks highlights, for the analyzed event, a spatial variability of the precipitation field for the hourly and sub-hourly duration, which cannot be captured by the current spatial density of the authoritative measurement stations (which it is also among the highest in Italy). Monthly total rainfalls and maximum intensity and short duration annual maxima time series recorded by the authoritative rain gauge network of the Genoa area are then analyzed. Results show that at distances even less than 2 km the variations in average rainfall depth cumulated over sub-hourly duration are very significant. Thus, extreme weather monitoring activity is confirmed as one of the most important aspects in terms of flood prevention and protection in urban areas. The integration between authoritative and citizen science networks can prove to be a valid contribution for monitoring this type of extreme events.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
<p>Liguria region is historically affected by severe hydro-meteorological events of... more <p>Liguria region is historically affected by severe hydro-meteorological events often resulting in dramatic death tolls and large socio-economic impacts. On 7-8 October 1970, Genoa, region capital city, was struck by the most catastrophic flood event of its history. On the evening of 7 October pre-frontal storms affected the western side of the city (Voltri, Prà and Pegli municipalities), while on 8 October 1970 an anticyclone block generated recurring convective systems that hit Genoa city and above all the Bisagno Valley. The heavy rainfall continued more than 24 h with highs at Bolzaneto rain gauge (Polcevera Valley, northwest of Genoa city center) where over 950 mm of rainfall in 24 hours was measured. Over the city center and the Bisagno Valley, 400 mm in 24 h was recorded. The Bisagno stream channels overflowed, submerging the city center. The 1970 event in Genoa City was also the most dramatic in terms of damage: 44 fatalities occurred and over 2000 individuals were evacuated.</p> <p>This study hindcasts the meteorological evolution of this event at high spatial resolution (1.5 km) and temporal one (1 hour) using the Weather and Research Forecasting (WRF) model by downscaling the ERA5 climatology developed by European Center for Medium-Range Weather Forecast (ECMWF). The weather hindcast scenario is compared with available meteorological observations as well as with recorded geomorphological impacts on Genoa city center and municipalities.</p>
Rapallo, with 30,000 inhabitants, is an important seaside tourist resort in the Eastern ligurian ... more Rapallo, with 30,000 inhabitants, is an important seaside tourist resort in the Eastern ligurian coast. It is internationally known since the beginning of the 20th century for elite tourism. Following the development of mass tourism, above all during 1960s and 1970s, the whole municipality has been affected by an intense urbanization \u2013 mainly due to construction of homes for holiday \u2013 which have strongly modified either the former landforms of the flood plain, either the surrounding slopes up to 150-200 m a.s.l. The area covered by urbanization has increased from approximately 45 ha in the early twentieth century, up to 175 ha in 1957, 600 ha in 1978 and 650 ha nowadays. This research is aimed to reconstruct the morphological transformations in a coastal environment, considering the historical changes due to human interventions and the related impact on geomorphological processes occurred since the 18th century. The study is based on field survey and on the interpretation and comparison among ancient and recent maps, aerial stereographic photos and orthophotos, on historic archive data, on drill analysis by several geotechnical investigations conducted on coastal-flood plain for civil and environmental purposes
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The complexity and non-linearity of the morphogenetic system which is responsible for shaping the... more The complexity and non-linearity of the morphogenetic system which is responsible for shaping the Earth's surface have been widely recognised by many authors who have documented the fractal nature of erosion. In this paper, two peculiar kinds of landforms are compared to point out ordered structures, i.e. triangular facets that arise in different geomorphic systems, due to the principle of morphologic convergence. Occurrence of triangular facets has been documented in mountainous areas in relation to base level changes and hydrographical network evolution; similarly shaped landforms are present even in recent tectonic uplift areas along faults. The spatial distribution of the two kinds of facets has been investigated in two river basins located in Liguria (northern Italy) and in a mountainous area in Oman. The results of this analysis document the different spatial features of the two kinds of facets.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Anthropogenic modifications at catchments scale may be reconducted primarily at soil sealing and ... more Anthropogenic modifications at catchments scale may be reconducted primarily at soil sealing and streams culverting, even if important consequences result from roads density and, more in general, infrastructures as they cause landscape fragmentation, and agricultural areas extension. Their most important outcomes in terms of hydrologic balance are the decreasing time of concentration and the increasing flood risk at catchment scale. The research introduces a methodological approach to classify the degree of anthropogenic modifications at catchment scale: clustering techniques have been applied to 508 catchments in a high-risk flooding sector of the Mediterranean region. Then, flood data recorded in the study area in the 1900-2018 period have been compared to clustering classification, pointing out the relationships with soil sealing and hydrographical network culverting in the catchment. The analysis has been performed considering fourteen subsets of 8 descriptive parameters each that differ in the evaluation of culverting in the terminal part of the hydrographical network; the analysis has been conducted identifying the optimal number of descriptive parameters and the corresponding best number of clusters on quantitative basis. The results show that three classes clustering is the more appropriate from a computational point of view. That division looks coherent with the features of the studied basins and is well correlated with floods occurrence in the last 100Â years. Finally, the proposed methodology of anthropogenic disturbance classification at catchment scale may be applied to other areas even adapting and implementing other descriptive parameters. Then, it may be used to support the planning of mitigation strategies in term of flood risk.
We present our research on the Prato Casarile landslide dam in Genoa city to illustrate the inter... more We present our research on the Prato Casarile landslide dam in Genoa city to illustrate the interactions between slope instability processes and structural stabilization interventions aimed to reduce the hazard in a densely-populated area. Analysis of the degradation of structural interventions constructed after flood events in 1953, 1970 and 2014 contributed to an improved mitigation strategy.. At the same time the slope instability processes intensively advanced, and regressive erosion quickly proceeded to the landslide dam threshold. The discontinuity in human interactions in a geomorphic system, after the initial hazard reduction, resulted in an increased threat that combined with a rise in vulnerability due to urbanization expansion. The research findings underline the necessity of constantly assessing the geomorphic evolution and active processes involved in order to determine the specific actions and interventions required to ensure the stability of the landslide dam. Finally, and more generally, we illustrated that anthropogenic interaction in the geomorphic system, specifically when finalized for hazard mitigation, needs to be continuously performed through both the monitoring and maintenance operation phases of the artificial structures.
This paper describes the anthropogenic landforms of the alluvial-coastal plain of Rapallo (Easter... more This paper describes the anthropogenic landforms of the alluvial-coastal plain of Rapallo (Eastern Liguria, NW Italy). Since the second half of the nineteenth-century Rapallo experienced a progressive urban sprawl that became particularly intense after the Second World War and severely modified the former landforms. The identification and mapping of morphological changes was performed through a multi-temporal comparison of historical and recent maps and aerial photographs, an analysis of geo-thematic maps and urban planning documents, an interpretation of stratigraphic data from boreholes, and a field survey activity. The main anthropogenic interventions that shaped the urban landscape of Rapallo were riverbed diversions and channelization, excavations, fillings, and embankments construction along the shoreline. These elements highlight the relevant extent of the human imprint on the pristine environment. Furthermore, the identified anthropogenic geomorphological features, combined with the local physiographic and climatic features, increased flood and sea storm hazards and risks.
Rendiconti online Società Geologica Italiana, Nov 1, 2016
After more than 25 years since the first studies, the Landscape Master Plan of Liguria has contri... more After more than 25 years since the first studies, the Landscape Master Plan of Liguria has contributed to maintaining the cultural and natural landscape. The current plan is made by three descriptive layouts and related regulations: the settlement and botanical settings represent the features of the landscape linked to buildings and vegetation. The geomorphological layout shows only the regulations, without any reference to Earth surface processes and landforms. This research suggests a methodology aiming at providing the plan with an engineering geologic suitable layout with the other settings. We propose eight geomorphological landscape units: all of them are connected with Earth surface dynamic factors, including man-made landforms and geodiversity values. A double key to the interpretation of this geo-map is suggested. The capital letters corresponding to regulations are maintained; we have inserted a new label linked to the geomorphological landscape unit. This updating may be integrated in the review processes of the Landscape Master Plan already started by Regional Authority.
This work presents the geomorphological features associated with the anthropic morphogenesis of t... more This work presents the geomorphological features associated with the anthropic morphogenesis of the Bisagno Stream catchment, combined with the geo-hydrological hazards associated with landslides and floods. This catchment is internationally known for its recurring high-magnitude floods and its geo-hydrological hazards associated with the large and widespread presence of elements exposed at risks. It experienced severe morphological changes due to anthropogenic interventions related to urban sprawl and agriculture. Anthropogenic modifications to the former landscape have been particularly widespread and pervasive over the coastline, the floodplain, and the slopes. They include a general alteration of the pristine landforms, excavation and landfill forms, channelization and culvert of riverbeds, and terraced slopes. The 1:20,000 scale map allows to assess the relationships existing among structures and infrastructures, anthropogenic landforms, and landslides and flood-prone areas. Thus, this tool provides relevant information for land-use planning and land management, in particular under the perspective of geo-hydrological hazards mitigation.
The impacts of climate change are becoming more widespread across the world, with hydro-meteorolo... more The impacts of climate change are becoming more widespread across the world, with hydro-meteorological extreme events on the rise, causing severe threats to nature and communities. Increasing trends in the frequency and intensity of floods and landslides have been projected by climate models. This necessitates the development of more effective measures such as nature-based solutions (NBS) which can complement grey infrastructures. Recent studies have identified knowledge gaps and limitations in existing research and tools that aid in spatial planning for the implementation of large-scale NBS and proposed new methodologies for the spatial allocation of large-scale NBS for flood risk reduction. This work presents a novel method for mapping the suitability of NBS addressing geo-hydrological hazards such as shallow landslides, debris flow, and rockfall, which are typically caused due to slope instability. This methodology incorporates landslide susceptibility mapping, and was used to cr...
9th International conference on Geomorphology, 2017
The Ligurian slopes facing the Tyrrenian Sea extend along the coast for nearly 300 km between Fra... more The Ligurian slopes facing the Tyrrenian Sea extend along the coast for nearly 300 km between France border to Tuscany: this stretch of territory presents more than a hundred catchments characterized by small floodplains. The slopes are very steep, while the alluvial plains are typically narrow and elongated. Ligurian catchments, except for the Roja and the Magra rivers, have common features: they can be distinguished in very small (<15 km2), small (15-150 km2) and medium basins (150-500 km2). Ligurian alluvial plains are historically characterized by floods that have caused damage for million of euro and tens of casualties. Over the last decades, an increase in alluvial events has been observed, both due to the variation in rainfall regime and in changes of land-use, which have heavily influenced the geomorphological processes. The great part of Ligurian urbanized areas are located in floodplains: these large areas represent the expansion of the small historical settlements and their original road connections. Through a comparison of old maps it was rebuilt the morphological evolution of Ligurian floodplains in historical times. Using historical maps of XVIII and XIX century, and regional maps for second half of XX century, the land-use and riverbed changes in the last centuries have been evidenced. The current status was assessed by Google Earth Pro platform. The secular human activities in Liguria have clearly modified the floodplain environment. The main channel, and even the minor hydrographic network, have showed major transformations over time. In many cases a narrowing and riverbed covering has been detected, especially in the medium-terminal stretch, with the aim to create new urbanizable areas for buildings and roads. Other widespread changes finally concern deviations and displacements of the riverbed, progradation of the coastline due to fill
In mountainous areas during intese rain events shallow landslides are often triggered adding thei... more In mountainous areas during intese rain events shallow landslides are often triggered adding their effect and enhancing the damaging consequences of flash flood. Many coastal area of the Mediterranean are exposed to such events, as recently largely happened in Italy, France, Spain and Greek. Large portions of the coastline mountainous territories have been settled and modified since ancient times with agricultural terraces, in order to practice the subsitence cultivation. This kind of anthropogenic modification of the slopes may be considered as an artificial immobilization of debris cover along steep slopes and, particularly after their abandonment, they can turn into sources of shallow landslides. Then terraces from belonging to soil and water conservation measures may represent a source of hazard if not properly mainteined. Considering the intense rain event that hit the Portofino promontory in 1915 causing strong damage to the Medieval monk Abbey in the iconic small San Fruttuoso village in northern Italy, a numerical modeling has been applied basing on historical testifying and the available evidences. A possible terraced area has been highlighted as a source area for the debris/mud flow that hit the Abbey and
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