Secondary tremors that come after the main tremor in a seismic series. The number of secondary tremors is usually directly proportional to the size of the main tremor. The tremors are less violent than the main event and the hypocentres concentrated in a limited area of the earth’s crust surrounding the hypocentre dof the main event.
AG - Maximum horizontal acceleration on hard and flat ground
Parametre describing basic dangerousness for reference seismic action on ordinary works (Class II of Building Techinical Regulations).
In general terms, it is the conditions of safety, hygiene, health and energy efficiency of buildings and facilities, evaluated on the basis of existing legislation. In seismic emergency, following an event, the "judgement of conformity" issued by the technicians who work during the emergency, is the possibility to continue using the building for functions that was used, reasonably protecting human life in case of a new tremor of intensity comparable to that already happened. In order to give the opinion of usability, engineers are engaged in the relief of the damage. The result has validity up to a shock later that significantly modifies the resistance of the building or until the ix of the building is complete, after which a technician prepares a final report on the practicability of the same building.
It is a mineral common in nature and due to its resistance to fire, heat and the action of chemical and biological agents it has been used for many purposes (in industry, building, etc.). However, since 1992 in Italy its use has been forbidden as it represents a potential hazard due to the dispersal of particles into the environment that when inhaled caused very serious diseases in man.
Modification in amplitude, frequency and duration of seismic shaking due to the specific lithostratigraphic and morphological conditions of a site. This can be quantified by calculating the ratio of the seismic motion on the site surface to that observed for the same seismic event on a hypothetical rigid rock outcrop with horizontal morphology. Any ratio greater than 1 is local amplification.
A method of examining the subsoil based on analysis of ambient seismic noise (micro tremors), small amplitude seismic waves caused by natural or man-made sources such as the waves in the sea, the wind, traffic, etc. By measuring the frequency of ground vibration, this analysis determines the thickness of “soft” surface soils, when the propagation velocity of shear waves Vs or the thickness of the surface is known. In both cases, measurement of micro-tremors permits subsoil geological model reconstruction used in seismic microzonation studies.
Seismic refraction analysis
A method of studying the subsoil based on artificial generation of seismic waves – e.g. sledge hammer, explosions – and measurement of the arrival times of the waves at a series of receptors (geophones) positioned in a line. The waves used are those subject to refraction phenomena along the surface of passage between means that increase in density with depth. This kind of analysis is very useful for defining the thickness of “soft” surface soils.
Geognostic analysis on site
Unlike laboratory tests, the geognostic analysis can be performed directly on the site of investigation, eg. penetration tests, geophysical tests.
Relating to man and his activities. The word comes from the Greek “anthropos” meaning man.
Transformed or adapted environment either to meet the needs of humans, or by human activity.
Sheltered areas for the population
Places for the installation of emergency dwelling areas with sufficient dimensions to accommodate at least one tent city for 500 people and field services. They are located close to water and electricity supplies, equipped with a waste water drainage system, and in areas not subject to risks of flooding, landslides, collapse of rocky masses, etc. The areas must be near a road junction or in any case easily reached, and the route must be marked on the map.
Assembly areas for relief operators and resources
Places in which the rational deployment of relief operators and resources in the intervention areas is guaranteed. They are located in safe areas in terms of risk of landslides, collapse and flooding, near water and electricity supply systems as well as waste water networks, and can be reached by way of safe routes, even with large vehicles. The Mayor of a municipality in which a MOC, Mixed Operations Centre, is set up, must identify at least one assembly area and mark the best route to gain access to it on the map. Relief for Municipalities served by the MOC depart from these areas.
Waiting areas for the population
Emergency reception areas for the population, which may be located in squares, open spaces, car parks, public or privates areas deemed suitable and not subject to risks – landslides, flooding, collapse – accessible by way of a safe route, possibly pedestrian, which is marked on the map. In these areas, the population receives basic information on the event as well as emergency comfort and support, as they wait for the sheltered areas to be set up.
Areas to be used for civil protection in the event of an emergency. These may be one of three types:
- Assembly areas for relief operators and resources
- Waiting areas for the population
- Sheltered areas for the population
Array (seismic antenna)
Device composed by seismometers or geophones following a specific geometry, that collects data in syncronous way within a central unit.
Activities aimed at checking the readiness and efficiency of the operating units and components of civil protection, through simultion exercises, verification of civil protection plans and, in general, practical verification of procedures to be followed in emergencies. (art. 6-11, L. 225/1992).
Phenomenon linked to fermenting processes that lead to a production of heat and gas, which, when exposed to oxygen, may become a point of ignition and start a fire. Spontaneous combustion hardly occurs in woods.
Document issued, depending on the competences, by the DPC or by the Regions to call attention to possible additional and specific events reported in the Bulletins Monitoring weather and/or criticalities. May relate to events already planned as particularly unusual or critical, or events in a manner not expected, but with time consistent with the scope and effectiveness of monitoring and verification of instrumental effects on the land, they evolve towards higher levels of criticality.
The document is made ??available to the National Service of Civil Protection, so that, on the basis of procedures uniquely and individually developed and adopted by the regions, are activated different alert levels that correspond to appropriate preventive measures and emergency management.
Notice of regional criticality
Document issued by the peripheral Functional Centre (when activated) or the central Functional Centre (based on the principle of subsidiarity) describing a general evaluation of ongoing events with moderate or high criticality level. The notice shows the type of risk and criticality level expected for at least the following 24 hours in each alert zone. The competence of the notice is of the President of the Regional Council or the delegated body - as provided for by the relevant regional regulations.
Notice of national weather
Document issued by the Civil Protection Department in the case of several regional weather alerts and/or weather events of importance beyond the regional scale.
The national weather warning is therefore the integration of regional weather alerts and assessments carried out by the Department in relation to the same regions whenever the relevant peripheral Functional Centre(s) has not yet been activated or is not autonomous regarding weather forecasts.
Notice of regional weather
Document issued by the peripheral Functional, when it gets activated and is autonomous in regard to weather forecasts, in case of events of recognized importance on a regional scale.