Figure 1 Map of the MedNet network stations, closed stations in red, operating stations in green.
Fig. 2 The tunnel where the instrumentation of the MedNet seismic station of Bardonecchia is installed (international code BNI).
The MedNet seismic network (Mediterranean Network) was born in the late 80s with two main objectives: to improve knowledge of the tectonic structure of the Mediterranean through the study of the source of strong and moderate earthquakes and to apply this knowledge to mitigate seismic risk in the region mediterranean. To these objectives must be added a more general but no less important one, the diffusion of broadband seismological culture in the region.
The MedNet project initially set out to install 12-15 broadband stations with a spacing of approximately 1000km. In 1988 the project was incorporated into the World Laboratory in Lausanne (Switzerland), an organization whose aim was to promote science in developing countries. The support of the World-Lab led to a rapid growth of the MedNet network with the establishment of scientific agreements with countries
North Africans and the opening of stations in Morocco, Algeria, Tunisia and Egypt. Over the past 15 years, the change in political conditions and the impressive technological development has led to an expansion of the prospects of the MedNet project which, while maintaining the two initial objectives unchanged, has expanded the area of interest to the Balkan region, a area affected by strong seismicity and with an important seismological tradition but poor in broadband seismic stations.
From the beginning, particular emphasis has been placed on the choice of sites, searching for mines, abandoned tunnels or sites in very remote places to enhance the qualities of the chosen seismometer, the Streckeisen STS-1, the best very broadband seismometer ever produced.
Over the years seismic noise analyzes have been performed (even retroactively) at MedNet stations, in particular through the spectral approach. At this link a database of power spectral diagrams (PSD) of acceleration noise at seismic station sites in the period 1994-2003 is available
Until the advent of real-time transmission systems for seismic data, data was exclusively recorded on site on magnetic tapes and sent by mail. This had the significant side effect of making maintenance of the station difficult, both due to the logistical and economic difficulty of reaching the site, and because months often elapsed between the breakdown, receipt of the magnetic tape and identification of the fault itself. A telephone connection with most of the sites guaranteed the possibility of downloading data "on demand" in the event of an earthquake and the Muscles automatic procedure in 1997 provided a rapid estimate of the magnitude of the Colfiorito earthquake after a few minutes.
Today, data transmission is ensured by a robust "real time" system which guarantees the usability of data in real time, the continuity of archived data and real-time monitoring of the stations.
Since its inception, the MedNet Project has been integrated into the Federation of broadband digital networks (FDSN), is a partner of IRIS ed ORPHEUS and, by distributing data to the international community quickly and automatically, it has contributed and continues to contribute to the study of seismology on both a global, regional and local scale.
Particular emphasis has been sought from the outset and continuously on the usability of the data by the foreign partners hosting the station in order to contribute with the MedNet station to their local seismic network and thus provide an additional tool for monitoring and the study of the seismicity of their country.
Today the MedNet network has 28 stations installed, of which 25 are operational, in 14 countries. The stations contribute to real-time monitoring of Italy and all host countries and are managed in collaboration with the following Institutes:
National Institute for Earth Physics, Bucharest, Romania
Dept. of Physics, Malta University, Malta
Geophysical Institute - Czech Academy of Science, Czech Republic
Institut National de Meteorologie, Tunisia
Geodynamics Institute – National Observatory of Athens, Greece
Bogazici University and KOERI, Turkey
GEOFON, GFZ German Research Center for Geosciences, Germany
NRIAG National Research Institute of Astronomy and Geophysics, Egypt
CNRST Center National pour la Recherche Scientifique et Technique, Morocco
Geophysical Institute - Bulgarian Academy of Sciences, Bulgaria
Seismological Center, Academy of Albania
University of Trieste and INOGS, Italy
CRAAG Center de Recherche en Astronomie Astrophysique et Géophysique, Algeria
Seismological Institute of Serbia
Montenegro Seismological Observatory, Montenegro
Seismological Institute of Banja Luka, Republika Srpska