## 2 Theoretical Basis about Risk
### Risk Management Principles  
Aim of risk management is to ensure that people, environment, and resources are protected from harmful consequences resulting from human activities or natural events. In other words, risk management makes it possible to plan strategies that are useful to contain hazards/threats of an activity or to reduce their potential damage [13].  
There are three strategies generally used to manage the risk: risk-informed, cautionary/precautionary, and discursive. The first refers to the planning of mitigation interventions deriving from the timely qualitative, quantitative, or semi-quantitative assessment of risky assets. The second is also defined as a resilience strategy and consists of risk containment, monitoring, and screening actions. The third one, on the other hand, is based on actions aimed at reducing uncertainties, explaining the evolutionary dynamics of risky processes, or involving people affected by risky activities [14].  
Therefore, Risk Management is the set of processes that are useful for identifying, analysing, quantifying, eliminating, and monitoring the associated risks with the performance of any activity and it consists of the logical-operational phases described below [2, 6, 15, 16, 17].  
The first step is to establish the context or to define the scope and objectives to be pursued, considering both the costs and benefits deriving from risk management.  
The second step of risk assessment comprises: (2.1) identification, (2.2) analysis, and (2.3) assessment of risks. Sub-step (2.1) is used to recognize potential dangers and threats that prevent the achievement of the objectives defined in the previous step (establish context). (2.2) is useful for understanding the nature of risky events as well as for determining the causes and consequences deriving from them. In (2.3), the information gathered from the identification and analysis phases is useful to establish whether the risk is acceptable or whether it is necessary to undertake mitigation strategies. In this phase, each identified risk is given a \"weight\" to draw up a list of priorities useful to guide the subsequent step of risk treatment. Weighting means estimating the level of risk according to the probability of occurrence of the event and its consequences.  
The following phase is the risk treatment, which includes: (3.1) the selection of the mitigation measures; (3.2) the implementation of the prepared plan; (3.3) the analysis and assessment of residual risk, i.e., the risk that remains despite the mitigation strategy undertaken. Mitigation strategies can be about retention actions, if the risk cannot be reduced, avoided or transferred; avoidance actions, if the source of risk is eliminated or the activity is interrupted; transfer actions, if the risk is transferred to another asset; control actions, if you act on the probability of occurrence of the event or its consequences on one of the two terms or both; acceptance actions, when there is no possible and/or sustainable mitigation intervention for which the risk is accepted as it is presented.  
Communication and Consultation and Monitoring and Review are also essential, but they are continuous processes that accompany all the phases of Risk Management [18, 19]  
Figure 1 summarizes the Risk Management Process (RMP) phases.