316 research outputs found
The ‘Deluge’ of 25 October 1822 in Genoa, Italy
Due to meteorological, geomorphological, and urban landscape features, the city of Genoa is frequently exposed to hydrological instability. Historical sources refer to floods since the early Middle Ages, while in the last few years the most impactful events with human losses took place in 2010, 2011 and 2014. Two centuries since its occurrence, using written reports, iconographical material and scientific reconstructions, the paper examines the flood of Genoa of 25 October 1822. In terms of rainfall data, surface effects and dynamics, this flood was one of the most destructive events of the city’s history
Urban geomorphology of a historical city straddling the Tanaro River (Alessandria, NW Italy)
The integration of \ufb01eld surveys, bibliographic research and multitemporal analysis of historical maps, aerial photographs and satellite images in a GIS environment, allowed the current and past geomorphological features of the old city of Alessandria and its surrounding areas, NW Italy, to be identi\ufb01ed and mapped. Their analysis provided an overview of the geomorphological evolution of the city that is strictly related to the historical vicissitudes occurred since the Middle Ages. Nowadays, the most representative landforms and deposits characterizing the urban landscape result from human interventions and are associated with ancient military facilities and infrastructures, a historical man-made channel network no longer recognizable, the Tanaro riverbed channelization, and the urban sprawl occurred from the second half of the nineteenth century onwards. This study represents a useful tool for urban planning and management and for raising the citizens\u2019 awareness of the urbanlandscape geomorphological features and evolution, and therefore the geo-hydrological risk
High-Resolution Lightning Detection and Possible Relationship with Rainfall Events over the Central Mediterranean Area
Lightning activity is usually associated with precipitations events and represents a possible indicator of climate change, even contributing to its increase with the production of NOx gases. The study of lightning activity on long temporal periods is crucial for fields related to atmospheric phenomena from intense rain-related hazard processes to long-term climate changes. This study focuses on 19 years of lightning-activity data, recorded from Italian Lightning Detection Network SIRF, part of the European network EUCLID (European Cooperation for Lightning Detection). Preliminary analysis was dedicated to the spatial and temporal assessment of lightning through detection in the Central Mediterranean area, focusing on yearly and monthly data. Temporal and spatial features have been analyzed, measuring clustering through the application of global Moran\u2019s I statistics and spatial local autocorrelation; a Mann\u2013Kendall trend test was performed on monthly series aggregating the original data on a 5
7 5 km cell. A local statistically significant trend emerged from the analysis, suggesting possible linkage between surface warming and lightning activity
Engineering geological map of the Chiavari city area (Liguria, Italy)
An engineering geological map at a scale of 1:10,000 of the Chiavari city area (Northern Italy) – a major tourist and economic attraction of the Ligurian East Riviera – is presented in this paper. The municipality land shows an excellent geomorphological case-study of the well-known Ligurian coast: a floodplain, fairly wide and inhabited, formed by several floods of the two main rivers, a hill hinterland, reasonably inhabited, developed in marly limestones and sandy shales flysch and the coast – featuring cliffs and narrow pebbly beaches – deeply modified. This map was compiled by combining available geological data with a new engineering geomorphological field survey and including geotechnical data which were obtained from studies carried out for town planning and building purposes. On the basis of the critical review of the available lithostratigraphic data from drilling, as well as geotechnical and geophysical analyses carried out between 1981 and 2010 on the municipality land, an engineering geologica..
Hindcast high-resolution simulation of the most catastrophic rainfall event in Genoa City (7-8 October 1970): hydro-meteorological and geomorphological analysis
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.
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
Wildfire and shallows landslides: a first statistical description in Liguria (North-West Italy)
GEOMORPHOLOGICAL INVESTIGATION AND MANAGEMENT OF THE GUVANO COMPLEX LANDSLIDE (CINQUE TERRE NATIONAL PARK, ITALY)
Heatwaves and physiological discomfort: the strange case of the year 2022 on the ‘Kiss Pass’ of Portofino Natural Park, Italy
Due to its cultural and landscape attractions, Portofino Natural Park is walked by thousands of hikers per year. In the Park's trail network, the path between Batterie and San Fruttuoso (known as “Passo del Bacio” translated to “Kiss Pass”) is one of the most popular because it is located on the edge of high rocky cliffs. Due to slope exposure and meteorological features, interventions by National Corp of Alpine and Speleological Rescue occur annually. The year 2022 was a record year, either for the particularly warm meteorological profile and the exceptional number of accidents recorde
Exposure\ua0to\ua0Geo\u2010Hydrological\ua0Hazards\ua0of\ua0the\ua0 Metropolitan\ua0Area\ua0of\ua0Genoa,\ua0Italy:\ua0A\ua0Multi\u2010Temporal\ua0 Analysis\ua0of\ua0the\ua0Bisagno\ua0Stream\ua0
Geo\u2010hydrological risk reduction policies are becoming a critical challenge for environmental sustainability, both at the national and international levels. The reason is twofold: On the one hand, climate change has increase rainfall frequency and intensity, while on the other, reckless urban expansion has increased exposure to such hazards over time. Italy is a country that is very vulnerable to flood and landslide hazard; the city of Genoa, which, in recent decades, has been frequently hit by severe floods, has risen to symbolize Italian geo\u2010hydrological risk. Recent studies on Genoa\u2019s geo\u2010hydrological hazard have focused on the analysis of hydrogeomorphological features of the Bisagno stream basin, yet their main focus was on hazard control. Very little research has been done to enhance the understanding of the source of risk in such catchments. This paper presents a study on the increased urban exposure and vulnerability to geohydrological hazard along the Bisagno stream catchment area over the last 200 years. Morphometric analyses were coupled with historical documents showing the evolution of the urban layout in this area. The results show that the \u201cBisagno Master Plan\u201d, a territorial planning strategy aimed at reducing geo\u2010hydrological hazard and risk, has not produced the expected benefits. In spite of the plan, critical changes in land use and the hydrographic network, along with uncontrolled anthropization of the Genoa metropolitan area, has continued over the last two decade
Heavy rains triggering flash floods in urban environment: A case from Chiavari (Genoa metropolitan area, Italy)
Between 10th and 11th November, 2014, heavy rainfall over a short period fell on the eastern Genoa metropolitan area. The geohydrological event had important ground effects, among them the simultaneous flooding of Entella and Rupinaro streams, in Chiavari city. In lower Lavagna valley, the main tributary of the Entella, a landslide caused two casualties, while serious damage to buildings and infrastructures were registered in Chiavari\u2019s Old Town and in the nearby communities of Carasco and Cogorno. In the Entella basin, the rainfall peaked at 60 mm/hour and
accumulated 220 mm in six hours. The levels of the streams rose instantly, showing concentration times of less than an hour. The Entella rose seven meters, flooding Carasco, Cogorno, and the Caperana neighborhood of Chiavari. Flash flooding of the Rupinaro stream caused water to rise to 1.5 m in Chiavari\u2019s historic core. Analyses were carried out of the weather conditions and the ground effects of the events; in addition, studies were made of the main causes of the geo-hydrological risk. In particular, variations in climate and uncontrolled urban development were the cause
of increased geo-hydrological hazards and vulnerability of this area, historically subject to flooding. Such conditions of risk are unacceptable, and urgent measures are required to mitigate the effects of heavy rainfall events
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