Sinkholes are sudden ground collapses with a sub-circular shape, varying in diameter and depth from a few meters to several hundred meters.
Mapping sinkholes and identifying risk areas are crucial for assessing a region’s susceptibility to hydrogeological instability.

The Italian Institute for Environmental Protection and Research (ISPRA) has recorded and studied more than 3,000 cases of natural sinkholes in plains, plateaus, and foothill areas. Detailed field surveys and analyses have been conducted on hundreds of cases.
Currently, over 300 areas susceptible to natural sinkholes have been identified, primarily along the mid-Tyrrhenian side of Italy, particularly in Friuli-Venezia Giulia, Lazio, Puglia, Abruzzo, Campania, and Tuscany.
The Adriatic side, due to its geological and structural features, is less affected by these phenomena, as are the Alps and the Dolomites, except for Friuli-Venezia Giulia and the plateaus of Veneto.

Anthropogenic sinkholes form another category, as they are related to underground cavities created by human activities (anthropogenic sinkholes), primarily for extracting construction materials. Many cities are affected, especially large urban areas built on land that has been historically mined, such as Rome, Naples, Cagliari, Palermo, Reggio Calabria, and Turin. Thousands of cases have also been recorded in smaller and mid-sized towns with extensive underground cavities.
Approximately 4,500 anthropogenic sinkhole events have been documented in Rome, over 800 in Naples, and several hundred in Cagliari and Palermo.

As of December 31, 2024, 16,729 cultural heritage sites are located in municipalities classified as areas with a high probability of strong earthquakes, representing 7.3% of the total cultural heritage.

The cultural heritage sites located within the high-hazard zone estimated by ISPRA amount to 4,948, representing 2% of the total, while those within the moderate-hazard buffer total 7,601, accounting for 3.3% of Italy’s cultural heritage (229,530 sites).

The indicator analyzes the distribution of large and small dams in relation to the seismic classification of the national territory (Map of seismic zones OPCM March 20, 2003, n. 3274 and subsequent integrations), the Landslide Index of the IFFI Project (Italian Landslide Inventory), and the distribution of landslide-prone areas. For the year 2024, the indicator shows that the water surface of artificial and heavily modified natural lakes (the water perimeter for large and small dams) in areas with a null Landslide Index (IF) constitutes 71.6%, while only 1.8% falls in areas with a higher IF (IF>30). In terms of seismic activity, 7.4% of large dams and 2.2% of small dams are are located in the most dangerous area (seismic zone 1), while 20.6% and 11.9%, respectively, are in the least dangerous area (seismic zone 4). Due to incomplete data on the distribution of small reservoirs at the national level, the result is considered partial.

In 2023, Italy experienced one of the hottest years in the last 150 years, second only to 2022. The average and maximum temperatures reached new records with October recording temperatures more than 3°C higher than the 1991-2021 average, marking the highest value since 1961. During the summer, intense heatwaves affected the country, with record temperatures of 48.2°C recorded on July 24 in Jerzu and Lotzorai in Sardinia, and 41.2°C in Rome in early August. Drought continued to be a significant problem, with Northern and Central Italy experiencing severe drought conditions in the first four months of the year, which later eased. However, in the last three months of the year, Sicily and parts of Ionian Calabria suffered from extreme drought with a significant precipitation deficit.
Extreme weather events affected several regions, causing severe damage. In May, Emilia-Romagna was devastated by two exceptional rainfall events, leading to flooding, landslides, and 17 fatalities. On November 2, heavy thunderstorms in Tuscany caused flooding and 8 deaths, with exceptional rainfall recorded in the provinces of Pisa, Livorno, Pistoia, and Prato.
In summary, 2023 was characterized by record temperatures, persistent drought, and extreme weather events that had a significant impact on various italian regions.

The indicator provides information about the landslide number and distribution in Italy. The recorded landslides exceed 635,000 (reference period 1116-2024) and affect an area of 25,004 km², accounting for 8.3% of the national territory.

The indicator provides information about the major landslide events caused fatalities, injuries, evacuations, damage to buildings, cultural heritage, and primary linear communication infrastructure or service networks in the national territory in the past year. The major landslide events occurred in 2023 were 192, with 11 deaths, 24 injuries, and damage mainly to the road network and buildings.

The indicator describes the seismic events that occurred in the reference year within the Italian territory, based on the Magnitudes recorded by the National Seismic Network (Rete Sismica Nazionale) of INGV. In 2023, no seismic event was destructive in Italy. Only one event exceeded Magnitude 5, but it had a very deep hypocenter, preventing any surface effects. Furthermore, 19 events with Magnitude between 4 and 4.9 occurred. The strongest earthquake, with a Magnitude of Mw 4.9, occurred near Marradi (FI). The number of earthquakes with Magnitude 2 or higher that occurred in 2023, concentrated mainly along the Apennine Range, the eastern Alps, and eastern Sicily, is comparable to the number of similar events in the previous four years.

According to the collected data, subsidence affects approximately 18% of Italian municipalities, primarily in Northern Italy, particularly in the Po Valley. In Central and Southern Italy, the phenomenon mainly affects coastal plains. The most affected regions are Veneto and Emilia-Romagna, where over 50% of municipalities experience subsidence.

The indicator is defined by the number of volcanic eruptions that have had significant effects in terms of interference with human activities over the course of the year. Regarding the reference year (2023), there was continuous eruptive activity from Etna and Strombolian activity with occasional intensity peaks at Stromboli.

The number of reservoirs classified as Large Dams, according to the Law of October 21, 1994, No. 584 and the subsequent Ministry of Public Works Circular 482/1995, is 529 (as of December 2023). Based on censuses provided by the regions up to March 2024, the total number of water bodies (artificial reservoirs, basins, natural lakes, ponds, marshes, etc.) is 33,646. Information on large dams is complete at the national level. For small reservoirs, censuses or estimates are available for all regions, although in some cases the information is partial and incomplete. It is estimated that at least 40% of these reservoirs contain dam structures.

The indicator provides information regarding cultural heritage exposed to landslide and flood risk along the national territory. There are 40,256 cultural heritage sites at landslide risk, of which 13,243 are in areas with high hazard P3 and very high hazard P4. There are 35,979 cultural heritage sites at risk of flooding in the medium hazard scenario (return periods between 100 and 200 years), and up to 53,844 in the low hazard scenario, which is the maximum expected scenario.

The indicator describes the environmental effects induced by earthquakes and represents the susceptibility of the Italian territory to such effects. Susceptibility depends on the varying degrees of seismicity present in different portions of the Italian territory and the local geomorphological and geological characteristics. It also provides a map of the ESI (Environmental Seismic Intensity) values reached during known seismic history in Italy, representative of the effects that may occur again in the future due to similar earthquakes.
In 2022, only one earthquake was recorded in which seismic-induced environmental effects were reported. This was the earthquake that occurred on December 4, 2022, in the Aeolian Islands, with a magnitude of 4.5, which induced modest collapse phenomena in some sites on Lipari and Vulcano.

The indicator provides information on the flood hazard conditions for the entire national territory, updated to 2020. Areas with high hydraulic hazard, prone to flooding with a return period between 20 and 50 years, account for 5.4% of the national territory (16,224 km²). Areas with medium hydraulic hazard, prone to flooding with a return period between 100 and 200 years, represent 10% (30,196 km²). Areas with low hydraulic hazard, prone to flooding during rare or extreme events, make up 14% of the national territory (42,376 km²).

The indicator provides information on the landslide hazard zones of the River Basin Plans (PAI) at the national level. The total area in Italy affected by landslide hazard and attention zones in PAI is 60,481 km² (20% of the national territory), of which 26,385 km² (8.7%) subject to the most restrictive land use constraints, with high P3 and very high P4 hazard. 

This indicator provides an overview of the population residing in flood-prone areas (population exposed to flood risk) at the national, regional, provincial, and municipal levels. In Italy, the population residing in areas with high hazard/probability is 4.1% of the total national population (2,431,847 people); those exposed to medium hazard/probability are 11.5% (6,818,375 people), while the population in areas with low hazard/probability is 20.6% (12,257,427 people).

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 surface faulting events associated with the reactivation of capable faults in Italy. These faults typically become active during strong earthquakes, but also in response to earthquakes with relatively low magnitudes if they are shallow, as occurs in volcanic-tectonic contexts, such as in the Etna region. Specifically, following the Fleri earthquake of December 26, 2018 (Mw 4.9, H = 1 km; INGV), the Fiandaca - Acicatena - Aciplatani fault system was reactivated, as it had been in the recent past.

Surface faulting along the Fiandaca fault was documented over a length of approximately 5 km. The rupture along the Aciplatani fault, however, was not co-seismic, but appeared several hours after the seismic event, with cracks opening a few centimeters that, after a few days, reached a total length of about 700 meters. These aseismic movements, known as creep, are common in some sectors of the Etna apparatus.

The damage related to the seismic event was primarily localized along the surface faulting zones, which had been affected by the same phenomenon multiple times in the past, including very recently. This highlights the importance of identifying areas with capable faults and considering them in land-use planning.

The faults reactivated in 2018 were already included in the ITHACA database, the inventory of capable faults in Italy developed by ISPRA, which provides the current state of knowledge about the distribution of faults in the national territory that are potentially capable of causing surface faulting.

The indicator provides an estimate of the level of exposure of urban areas to surface faulting hazards. For each seismogenic zone in the ZS9 zoning, the indicator measures the areal extension of urbanized areas exposed to surface faulting hazards due to their proximity to capable faults (ITHACA Catalog). These faults are delineated considering the predominant kinematics of the fault, with an extension that depends on the maximum expected displacements.

The most critical situations are confirmed in eastern Sicily, particularly in the Etna area. A comparison with the last assessment (in 2014) shows an increase attributable to the greater expansion of urban areas near capable faults, as well as to the higher number of capable faults included in ITHACA, due to the progressive improvement in knowledge about the recent tectonic activity of certain structures.