SEISMIC SURVEILLANCE SERVICE

Videowall showing the seismic activity of the sequence in central Italy, photographed on 30 October 2016 in the Sala di Surveglianza Sismica in Rome.

Seismicity in the month of December 2018. The earthquakes were located by the staff on duty in the Seismic Surveillance Room of Rome.

The earthquakes located on Etna by the Operations Room of the Etna Observatory in Catania in the period 24-31 December 2018.

Earthquake swarm at Campi Flegrei.

The National Institute of Geophysics and Volcanology (INGV) is the Competence Center of the National Civil Protection System which deals with seismic surveillance of the national territory.

INGV communication is conducted according to three guiding principles:

• provide the Civil Protection Department (DPC) with precise information regarding the seismic phenomena in progress to allow the DPC to manage the criticality in progress and/or any emergency;
• provide information quickly also to the competent local authorities (such as regional civil protection offices, prefectures, municipal offices), in addition to and consistently with what has been done by the DPC;
• reduce, compatibly with the needs of civil protection, the time required for the release of information of general interest to the media and the public, to prevent an urgent request from the latter from being addressed to non-competent subjects.

Following these principles, INGV provides via press releases the hypocentral data and the magnitude, initially, calculated automatically, without verification by the seismologist; subsequently the data verified by the seismologist on surveillance duty are communicated. The communication of events is always carried out for earthquakes with a magnitude Ml ≥ 2.5 (except for the volcanic areas of Campania for which the thresholds are lower), while for less energetic events it occurs only in the event of reporting resentment by the population.

Important information, such as historical data, seismotectonic context, shaking maps, references to hazards, processing and analysis of the information collected are provided to the DPC and to the public through reports and through the seismic event web pages (see example http://cnt.rm.ingv.it/event/12697591).

The quality and accuracy of information improves as time has passed since the occurrence of the event, information provided quickly, or while the event is in progress, is subject to greater uncertainty. This depends on the fact that over time more data becomes available and therefore more sophisticated analyzes can be carried out that require more processing time.

Seismic surveillance of the national territory and in the neighboring areas is the responsibility of the Seismic Surveillance Room managed by the National Earthquake Observatory (ONT) in Rome. For seismic events that occur in the volcanic areas of Campania (Vesuvius, Campi Flegrei and Ischia) and Sicily (Etna, Stromboli, Vulcano, other Aeolian islands and Pantelleria), the Monitoring Room of the Vesuvius Observatory (OV) is responsible, respectively. Naples and the Operations Room of the Etna Observatory (OE) in Catania. Seismic surveillance of the Colli Albani is the responsibility of the National Earthquake Observatory (ONT) in Rome.

Among the reports of phenomenologies and events on volcanic complexes that INGV makes available to the DPC and the public, connected with the state of volcanic activity, there are seismic events in volcanic areas. The communication thresholds for seismic events are different for different volcanic areas.

In addition to all the information that is given for seismic events on the national territory in these particular areas, the DPC is also notified of the occurrence of events of lower magnitude and the occurrence of seismic swarms, i.e. more seismic events, even of very low magnitude occur rapidly over time and which can be indicators of variations in the state of equilibrium of volcanic complexes. Each volcano has a specific definition of the magnitude and frequency thresholds of seismic events over time, beyond which the occurrence of a seismic swarm is declared.

Communications between INGV and the DPC also provide for the sending of weekly Bulletins and Event and Sequence Reports. The Bulletins contain a description of the seismic activity on the national territory and of the state of the monitoring networks; are issued on a weekly basis.

The event and sequence reports are aimed at describing in a more complete and exhaustive way the overall seismotectonic framework for earthquakes or seismic sequences, occurred or in progress, of which INGV has already provided information by means of press releases. They are based on the information present in the INGV databases and on data from other monitoring networks, possibly supplemented by what was observed in ad hoc site inspections. The Event Reports are drawn up for all seismic events of magnitude Ml ≥ 4.0 that occur on the national territory.

In the event of significant seismic events, a Crisis Unit is set up at INGV which coordinates all the actions to be carried out in an emergency.

As regards the surveillance and monitoring activities of volcanic areas, INGV makes available the reports of phenomenologies and events, as well as assessments of hazards associated with the state of volcanic activity and possible evolutions, through the following types of documents, differentiated according to the contents , the methods and timing of issue: Press Releases, Extraordinary Press Releases, Bulletins, Reports.

These documents are issued, for each volcanic complex, by the reference INGV Section, and made available to the DPC, the regional civil protection structures, the Prefectures responsible for the area and other Centers of Expertise that may carry out monitoring activities on the specific volcano, under specific collaboration agreements with the DPC.

TIMES and COMMUNICATION OF LOCATIONS    THE SURVEILLANCE ROOMS