D58 Azores Risk Assessment Implementation Report – CVUA

The research produced within RETINA project, in previous workpackages was integrated in the CVUA procedures in what concerns hazard and risk assessment, providing Azorean Civil Defence with practical information to be applied for land-use planning or during crises management.

To demonstrate the practical application of this research, CVUA and SRPCBA performed in 28-29 May 2005 a simulation exercise where a geological disaster scenario was created to provide scientific and civil defence teams an outline for their actions. The area chosen was Povoação County, target of most of the research made during RETINA project and a region with an extensive historical record of major volcanic, seismic and landslides catastrophes.

CVUA had seven groups operating during this exercise, developing office and field activities: (1) Data Acquisition and Coordination Centre; (2) Geographic Information System; (3) Landslides; (4) Geochemical Monitoring; (5) Geodetic Monitoring; (6) Volcanic Seismology; (7) Volcanology.

Partners from Retina and Foresight projects and EU observers joined CVUA and SRPCBA groups in order to follow their activities during the exercise.

SCENARIO FOR THE EXERCISE

The scientific scenario for this exercise, defined by CVUA, was based in historical events like the 1932 and 1935 earthquakes. In essence, the scenario involved the occurrence of a strong earthquake of tectonic origin, with epicentre located in the sea, at about 15 km to southeast of Povoação County, S. Miguel Island (Fig. 21).

Fig. 21: GIS map of S. Miguel island produced with geographic information ( parishes and urban areas) and seismological data(Epicentre and seismic intensity isolines) included in AZORIS database.

The event caused several fatalities and considerable destruction in the county. Numerous landslides were triggered increasing the destruction in areas near unstable slopes and were responsible by the obstruction of some important roads. Hours later strong aftershock produced new landslides responsible for the temporary isolation of two villages (Faial da Terra and Água Retorta).

CVUA operational groups went to the most damaged areas in order to (1) map the landslide events and analyse potential hazardous areas and (2) characterise infrastructures and buildings damages and vulnerability (Fig. 22). These elements were presented to SRPCBA to provide support for their decisions.

Fig. 22: Example of a vulnerability map produced during the exercise. Estimation of Faial da Terra village buildings vulnerability to seismic action (EMS-98).

In a second stage seismic activity migrated inland towards a potentially active volcanic area showing signs of potential volcanic unrest in an area that encompass Furnas and Achada das Furnas volcanic systems.

Considering the possibility of an activation of one of those volcanic systems, geophysical, geochemical, and geodetic monitoring groups reinforced the networks and increased the observations. In consequence Volcanic Alert Level was raised.

Volcanology group produced scenarios based on historical eruptions in order to provide elements of volcanic hazard to SRPCBA.

Conclusions:

The performed exercise demonstrated the importance of a strong link between scientists and civil defence agents during crisis management. One of the main achievements of RETINA project was the to improve the links between those two groups which will have positive implications in a future event. At present, S. Miguel island is experiencing a seismic crisis, which already triggered some landslides. The RETINA research in what concerns coupling events is being applied and information is being provided to SRHE/SRPCBA.