Activities - Seismic risk
The Civil Protection Department carries out activity to assess, prevent and mitigate seismic risk in Italy, Centres of Competence or operating units.
Science today is not yet able to forecast the exact time and place for future earthquakes. The only forecast possible is of a statistical kind, based on knowledge of past seismicity in Italy therefore on the recurrence of earthquakes. We know which areas in the country run a high seismic risk, for earthquake frequency and intensity and therefore where it is most likely that a big seismic event will happen, but it is not possible to exactly determine when it will happen.
Probabilistic forecasting allows hazardous areas to be identified and classified according to the probability of strong earthquakes and their expected frequency. For greater accuracy when calculating the interval of time in which a given location will most probably be hit by an earthquake, we would need to know how much energy is accumulated in the seismogenic structure, which may trigger off an earthquake in that place and the way in which the energy is released, in other words, a little at a time with many low magnitude shakes or with a few very strong events. But even in-depth study of seismogenic structures will not enable us to establish the exact moment the next earthquake will strike.
Over recent years science has made considerable progress in the study of seismic precursors, in other words the chemical and physical parameters of the ground and underground subject to the variations that can be observed before an earthquake happens. In the future, systematic study of these precursors could allow the initial moment of the earthquake to be fixed, even if false alarms must be avoided, which could prove to be even more harmful.
Research into earthquake precursors has concentrated on:
• Seismological precursors: before a big seismic event a series of microtremors may occur, only detectable by instruments.
• Geophysical precursors: anomalies in the P and S wave speeds, variations in magnetic and electric characteristics of rocks.
• Geochemical precursors: variation in underground waters of the concentration of some chemical elements, in particular of radon, a radioactive gas.
• Geodetic precursors: alterations in the level and slope of ground surface.
Despite comprehension of the phenomenon and confirmation of the validity of the genetic model for earthquakes advanced by seismologists, forecasting of earthquakes based on precursors has so far brought disappointing contradictory results. No precursor happens regularly before each important earthquake, for this reason research is moving towards simultaneous observation of different phenomena. For example, while it is true that animals behave unusually before a seismic event, it is not always true that an earthquake will occur when cats or dogs behave in a certain way. To prevent the effects of a seismic shake, the risk factors must be reduced, acting in particular on the quality of building. Prevention in the form of building well is therefore still the only effective way of reducing the consequences of an earthquake.
Office III– “Seismic and volcanic risk” of the Department establishes criteria and methodologies for the assessment and mitigation of seismic risk, develops technical and scientific skills for predicting the impact of the earthquake on the territory
and works for the optimization of operations in emergency and post-earthquake reconstruction.
In addition, provides guidance on the seismic classification and regulations for buildings in seismic zones, gives support and assistance to other central and peripheral of the State and monitors the areas to quickly determine the characteristics and effects of earthquakes. Promotes and implements initiatives to raise awareness on issues of seismic risk and prevention
(Earthquakes of Italy).
These tasks are carried out with the support of scientific and operational centres of excellence for seismic risk: INGV - National Institute of Geophysics and Volcanology, for seismological aspects, ReLUIS - Network of University Laboratories of Seismic Engineering and Eucentre - European Centre for Training and Research in Earthquake Engineering for the engineering aspects. An effective strategy for mitigation of the seismic risk requires a constant effort to improve knowledge about the causes of the phenomenon, deepen studies on the behaviour of structures subjected to seismic action and improved action in an emergency.
The seismic risk, in fact, in addition to the occurrence of the physical phenomenon, is inextricably linked to the presence of man. Since it is not possible to predict the occurrence of earthquakes, the only applicable strategy is to limit the effects of the phenomenon on the man-made environment by implementing appropriate policies for prevention and reduction of seismic risk.
- Improving knowledge of the phenomenon, through the monitoring of the area and properly assessing the danger to which built-up areas, population and infrastructure systems are exposed;
- Implementing policies to reduce the vulnerability of older buildings, "relevant" buildings (schools, monuments), "strategic" buildings (hospitals, emergency management facilities), by optimizing the resources used to recovery and redevelopment of built-up areas;
- Upgrading the seismic classification and regulation;
- Developing seismic micro-zoning studies for a correct use of ordinary tools of planning to achieve over time a land-use planning that takes into account the seismic risk and to improve the operation and management standards of emergency after an earthquake;
- Acting on the population with a constant and vigorous action of information and awareness.
After a seismic event, the first information necessary for immediate aid are the size, extension and localisation of damage.
For this reason it is indispensable to have assessment tools based on damage scenario simulations that allow planning and management of emergency response in real time, even before inspections take place. These tools must be combined with activity to promptly assess the damage, to consolidate preliminary analysis and forecasts based on the first instrumental data readings of the seismic monitoring network. In the event of earthquakes over the damage limit, prompt macroseismic inspections are carried out with the aim of orienting and coordinating aid and resources during the emergency stage. This inspection consists of observing the level of damage and its distribution in the different locations hit, giving each one a macroseismic intensity value expressed in degrees on the Mercalli Cancani Sieberg (MCS) scale.
During the first hours after an earthquake, it is fundamentally important to know as soon as possible the extent of the event and its impact in the area and on the population in order to activate, size and organise aid suitably. In this sense, the particularly negative experience following the Irpinia earthquake in 1980 was used by the Department to set up a territorial information system (Gis) able to generate a simulation scenario in semi-real time of the consequences of the seismic event. In the case of an earthquake of a large magnitude, the National Institute for Geophysics and Volcanology transmits the focal parameters to the Department (magnitude and coordinates) of the event. An automatic procedure automatically generates a report that is sent to the Civil Protection within 10 minutes after the event. The report contains data, maps and information relative to all the municipalities included in a radius of 100 km from the epicentre with reference to:
• description of the territory (man-made, physical and administrative aspects; characteristics of buildings and infrastructures; seismic monitoring networks)
• hazard (seismogenic zones, past earthquakes, isoseismal lines and relief mapping, attenuation of ground movement)
• vulnerability (building assets, schools, hospitals, road and rail network)
• exposure (characteristics and distribution of the population living in each section investigated)
• preliminary assessment of damage and losses (damaged houses and those unfit for use, estimate of dead and injured, estimate of economic damage).
In order to effectively manage a post-earthquake emergency, quick damage and agibility assessment activities on public and private buildings and on buildings of cultural interest play a fundamental role. In fact, these activities aim to safeguard public safety, guarantee the timely return of the population to their homes and carry out the first urgent measures to secure the buildings in order to reduce the disadvantage of the people affected and possible further damage.
The Fire Fighters are involved in these contexts and, within their powers and responsibilities, they carry out quick inspections to verify and facilitate the viability of roads, monitor the usability of buildings and mark the areas to be subjected to preventive interdiction. On the other hand, the National Civil Protection Service's technicians, equipped with adequate professional skills and suitably trained, have the task of proceeding with the precise, albeit expeditious, analysis of the buildings, carrying out inspections with the aid of technical evaluation sheets (Scheda Aedes and GL-Aedes). For this purpose, the Decree of the President of the Council of Ministers of 8 July 2014 established the National Technical Unit which works in order to optimise, according to a pre-established scheme in time of peace, the mobilisation of technical experts for post-seismic agility verifications in emergencies.
Technicians from the Public Administration, voluntary organisations and professional associations and colleges to be enrolled in the National Technical Team are addressed by the Operational Guidelines of 29 October 2020, aimed at integrating their previous skills and professional experience with knowledge that will allow them to be used in the post-seismic emergency.
These post-seismic emergency activities require a considerable degree of standardisation of procedures and constant quality control in the management and organisation of surveys and inspections. With the aim of defining coordinated and integrated ways of organising and carrying out these activities, on 12 February 2021, the Department issued the Operational indications for the connection and coordination of post-seismic dispatchable technical inspection activities.