Descrizione 1
Carla Iadanza, Alessandro Trigila
The indicator provides an estimate of the population exposed to landslide risk (personal damage risk: deaths, missing, injuries, and evacuations) on a national, regional, provincial, and municipal basis. In Italy, the population at landslide risk residing in areas with high and very high landslide hazard (P3+P4) amounts to 1,303,666 inhabitants, equal to 2.2% of the total population.
The indicator provides information on the population at landslide risk. The population exposed to landslides refers to the resident exposed to personal damage risk (deaths, missing people, injuries, and evacuations). The estimate was made using input data from the national ISPRA Mosaic (v. 4.0 – October 2021) of areas with landslide hazard (very high P4, high P3, medium P2, moderate P1, and areas of attention AA), as delineated in the River Basin Plans (PAI) prepared by the Basin District Authorities (formerly Basin Authorities) and the Autonomous Provinces of Trento and Bolzano; the 15th Census of the Population by ISTAT (2011), and the ISTAT administrative boundaries (2021).
To provide an estimate of landslide risk population on a national, regional, provincial, and municipal level.
Collection, processing, storage, and dissemination of data related to soil protection and hydrogeological instability along whole national territory (Article 55 of Legislative Decree 152/2006 “Environmental Regulations”; Decree-Law 180/98 “Sarno Decree” converted into Law 267/1998, DPCM of 29/09/98 - Guidance and Coordination Act, Law 365/00);
Outcome indicator within the framework of the 2014-2020 Partnership Agreement between Italy and the European Commission (Thematic Objective 5 – Promote adaptation to climate change, risk prevention, and management);
Indicator used for the allocation of funds among the Regions (DPCM December 5, 2016) within the National Plan against Hydrogeological Instability.
Descrizione 2
Trigila A., Iadanza C., Bussettini M., Lastoria B. (2018) Dissesto idrogeologico in Italia: pericolosità e indicatori di rischio. Edizione 2018. ISPRA, Rapporti 287/2018 (ISBN 978-88-448-0901-0)
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Qualificazione dati
The 2011 ISTAT Census is available at the link: https://www.istat.it/it/archivio/104317
The ISPRA National Mosaic of Landslide Hazard is published on the HydroGEO Platform: https://idrogeo.isprambiente.it/.
National, Regional, Provincial, Municipalities
2021
Qualificazione indicatore
The estimate of risk landslide population was made by intersecting, in a GIS environment, the ISPRA national mosaic of landslide hazard areas (PAI) with the 402,678 sections of the 2011 ISTAT Census. Since the exact location of the population within the sections is not known, the residents were uniformly distributed within each section. The number of people exposed was then calculated using the proportional method, multiplying the percentage of landslide hazard area within each census section by the population residing in that section.
Vulnerability, which represents the degree of loss of the element at risk that could be damaged during an event, was conservatively set to 1, as its assessment would require knowledge of the magnitude of the landslide phenomena (speed and volume) as well as knowledge of the behavior/resilience of different population categories (e.g., elderly, children, and non-autonomous persons). Vulnerability can also vary depending on the time of year (summer/winter), the day of the week (weekday/holiday), and the time of day (day/night) when the event occurs.
In Italy, the population at landslide risk living in areas of high and very high landslide hazard (P3+P4) totals 1,303,666 inhabitants, which is 2.2% of the total population.
Currently, it is not possible to evaluate a trend for this indicator due to the limited historical series available (2015, 2018, 2021).
Dati
Tabella 1: Popolazione a rischio frane su base regionale – elaborazione 2021
ISPRA
* Popolazione residente (Censimento ISTAT 2011) aggregata su limiti amministrativi regionali ISTAT 2021
Tabella 2: Popolazione a rischio frane su base provinciale – elaborazione 2021
ISPRA
* Popolazione residente (Censimento ISTAT 2011) aggregata su limiti amministrativi provinciali ISTAT 2021
Figura 1: Popolazione a rischio residente in aree a pericolosità da frana elevata P3 e molto elevata P4 PAI su base comunale – elaborazione 2021
ISPRA
The population at landslide risk in Italy is as follows:
499,749 inhabitants in areas of very high hazard P4 (PAI);
803,917 inhabitants in areas of high hazard P3;
1,720,208 inhabitants in areas of medium hazard P2;
2,006,643 inhabitants in areas of moderate hazard P1;
676,948 inhabitants in areas of attention.
If considering the two highest hazard classes (P3+P4), the population at risk totals 1,303,666 inhabitants, which is 2.2% of the total. When all hazard classes are considered, the population at risk reaches 5,707,465 inhabitants (9.6%). The regions with the highest values of population at landslide hazard (P3 and P4 areas) are Campania, Tuscany, Liguria, Sicily, Lazio, and Emilia-Romagna (Table 1).
Table 2 presents the distribution of the exposed population at the provincial level, and Figure 1 shows it at the municipal level. Municipalities in the first class (with zero inhabitants at risk) may still face non-zero risk due to the potential presence of residents in areas classified as having lower hazard levels.
An increase of 1.7% in the population at landslide risk in P3 and P4 areas compared to the 2018 processing is recorded, which is due to the integration/revision of the mapping of landslide hazard areas, carried out by the Basin Authorities and the Autonomous Provinces of Trento and Bolzano (see Indicator for Landslide Hazard Areas PAI).