|Observatories and Research Facilities for EUropean Seismology|
|Volume 3, no 2||December 2001||Orfeus Newsletter|
Two meetings held in Italy on seismological data acquisition, exchange and analysis in Central EuropeGiovanni Costa1, Alberto Michelini2, Andrea Restivo2 and Peter Suhadolc1
On September 6th - 7th and 14th - 15th, 2001, two important events , focusing on the interaction of seismic networks and seismological data exchange, took place in Trieste and Udine, NE Italy. Scientists from many European and overseas seismic monitoring institutions gathered and exchanged mutual knowledge on their installed instrumentation, data analysis procedures and research activities.
Earthquakes in the South-Eastern Alpine domain are concentrated at or close to the borders between Slovenia, Austria and Italy (Friuli-Venezia Giulia Region, FVG), see Figure 1. This area has experienced several destructive earthquakes in the past with large costs paid both in terms of casualties and of damage to cities and infrastructures. The most recent examples are represented by the 1976 Friuli and the 1998 Bovec-Krn Mountain earthquakes. Different seismic networks are now operating in these regions with the purpose of collecting data to study and monitor the ongoing seismicity. Overall, this enables network operators to provide counselling to the authorities at the occurrence of a major earthquake. The example of the Bovec-Krn Mountain earthquake (ML = 5.9), located within the Slovenian borders but just a few kilometres away from Austria and FVG, demonstrated that the integration of services provided by the neighbouring networks is essential for a rapid and efficient intervention of emergency organizations and rescue parties. The current co-operation among the different seismological institutions operating in this area, including chances and ways for its future development, has been one of the main topics discussed in these meetings.
Figure 1. Plan view map of the border region between NE-Italy (Friuli-Venezia Giulia), Austria and Slovenia. The map shows the existing, permanent seismological instrumentation and the M>2.5 seismicity from 1977 to 2000 taken from the OGS catalog. The red stars refer to the Friuli 1976, M=6.4, earthquake (to the west) and the Krn Mnt. 1998, M=5.9 earthquake. The map has been prepared using the GMT public software of Wessel and Smith.
Beyond Frontiers: Seismic Networks in the Southern AlpsThe workshop "Beyond Frontiers: Seismic Networks in the Southern Alps" was held at the Dipartimento di Scienze della Terra (DST) of the University of Trieste and was organized by the DST and the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS) under the auspices of the Direzione Regionale della Protezione Civile della Regione Autonoma Friuli-Venezia Giulia (PC-FVG). Its aim was to lay down the basis of a close communication among the different institutions managing seismic networks and the Civil Protection authorities involved. It provided guidelines to improve the service to the community, granting a more intense collaboration and integration among the various organizations responsible of handling future emergencies. The workshop was structured in two parts: status and perspectives. The current status of the existing seismic networks and of the level of scientific and emergency interaction and planning was first reviewed. An outlook on the actions needed to improve the quality of the service that such networks provide to the Civil Protection Agencies and the level of their trans-frontier integration was then drawn also through the experiences shared by a few invited experts. The feasibility of a real-time data exchange among four stations (OBKA - Seismic Network of Austria, LJU - Environmental Agency of the Republic of Slovenia, CUSQ - OGS, TRI - DST/ OGS) in the Austria-Slovenia-Italy border region was demonstrated during the Workshop with a real-time on-line connection, see Figure 2. A round-table discussion on the covered subjects eventually produced a final document of intents and recommendations for an improved future cooperation.
Integrating the Seismic Monitoring in Central EuropeThe workshop conclusions were next presented at the conference "Integrating the Seismic Monitoring in Central Europe", which was held at the Udine Castle and was organized by the OGS and the PC-FVG, with the collaboration of the DST, the Istituto Nazionale di Geofisica e Vulcanologia (INGV), the Agenzia Nazionale della Protezione Civile and the Dipartimento per i Servizi Tecnici Nazionali (DSTN) and the patronage of the City of Udine. This event provided public administration bodies with a window on the state-of-the-art of local seismic monitoring finalized to fast and reliable Civil Defence alert and on the perspectives for future coordinated efforts. Unconditional support to this initiative was given by the people in charge of the above mentioned Institutions who took part to the meeting.
Real-time data exchange agreementAs an important and tangible result of these works, an international scientific agreement for "real-time" seismological data exchange in the Alpe-Adria region among the Zentralanstalt für Meteorologie und Geodynamik, Hauptabteilung Geophysik, Wien, Österreich (ZAMG), the Agencija Republike Slovenije za Okolje, urad za seizmologijo, Ljubljana, Slovenija (ARSO), the DST and the OGS was reached and will be formally signed before the end of the year.
Coverage of these two events is also available on a dedicated web-page. A CD-Rom containing the presentations given at the workshop and the conference is under preparation and will be soon available for request through such web-page.
Seismic monitoring in Central-Eastern Europe: present and futureSeismic monitoring in the FVG region was illustrated in its development from the deployment of the WWSSN TRI station in Trieste through the seismic crisis following the May 6th, 1976 Friuli main shock, to the present configurations and improvement plans. Presentations were given on the Rete Sismometrica del Friuli-Venezia Giulia (RSFVG) managed by the Centro di Ricerche Sismologiche (CRS) of OGS, the Rete Accelerometrica del Friuli - Venezia Giulia (RAF) managed by the DST and the existing collaborations with national institutions such as the INGV and the Rete Accelerometrica Nazionale (RAN) managed by the SSN as well as the IGG seismic network of the University of Genova also active in Northern Italy.
Other seismic networks which operate in neighbouring Countries - France, Switzerland, Austria, Slovenia, Croatia, Hungary, Slovak Republic, Czech Republic and Bavaria in Germany - were also described. Ongoing international collaboration projects were particularly underlined together with the existing interactions of each single network with the local civil authorities and the organization of automated seismic alert systems.
Improving real-time data exchangeImprovement plans towards faster and fail-proof systems of real-time collection and exchange of high-quality seismic data were also analysed from the standpoint of each scientific institution. Appropriate site selection was recognized to be the first step in order to obtain clean seismic records as well as to avoid coverage overlaps with neighbouring networks in monitoring border regions, hence reduce costs. Transition to digital acquisition instrumentation has been completed or is on course for all networks. Telemetry on dedicated frequencies is widely adopted for data transmission and satellite systems will be soon implemented too to ensure permanent network functionality. Data processing, organization and archiving issues were finally covered, urging the need for introducing database mirroring systems.
Seismo-tectonics of the Southern AlpsState-of-the-art-knowledge about the seismo-tectonic features of the Southern Alps domain was also offered at the Trieste workshop and Udine conference along with more theoretical discussions on seismic moment tensor determinations. The present state of stress in the region was reviewed and possible scenarios of future major earthquakes exposed along with seismic hazard microzonation topics derived from example studies of local seismic response and measurements of local deformation.
Advanced data handling experiencesThe above discussions and the outline of future real-time data exchange and collaboration programs greatly benefited from the data handling experiences brought by invited speakers representing the most important national and international networks and organizations. Centralized collection and archiving of seismological data acquired world-wide is not in contrast with distributed computing and data dissemination concepts. The necessity of data redundancy for precaution purposes was indeed remarked as well as the need for flexibility in data exchange issues to overcome problems of dealing with different data formats. The most advanced data analysis methods were also illustrated for real-time source parameters inversion and hypocentral determination as well as state-of-the-art forward modelling and crustal deformation analysis techniques.
Towards future network integration: a joint statement drawn by the participants to the 6-7 September Trieste workshop and adopted at the 14-15 September Udine conference.The participants to the Trieste Workshop concluded that there is an urgent need for closer network integration with real-time data exchange and sharing of seismic database information in border regions, especially for Civil Defence purposes.
Technical problems of interconnecting seismic networks were discussed and defined at the Workshop. Some of the problems have already been solved and others are under investigation.
The feasibility of a real-time data exchange among four stations (OBKA - Seismic Network of Austria, LJU - Environmental Agency of the Republic of Slovenia, CUSQ - OGS, TRI - DST/OGS) in the Austria-Slovenia-Italy border region was demonstrated during the Workshop with a real-time on-line connection. Currently, the DST/OGS station TRI is already included in the Slovenian and Austrian monitoring networks.
The next step was identified in the enlargement of the real-time data exchange to all networks operating in this region:
A formal agreement among the Civil Defence Authorities of the involved countries regarding this network integration is as well needed.
Following this agreement, common periodic reports by the people in charge of the integrated networks should be produced to the Civil Defence authorities.
Once this regional network integration will be accomplished, proved to work and officially recognised for the benefit of both Science and Civil Defence needs, it is envisaged for the future to share this experience and to provide know-how to other regions.
Better co-ordination among involved parties was also recommended with respect to future station deployment/installation in order to minimise overlap and reduce costs.
Effective network integration requires data redundancy and mirroring of databases to ensure data integrity and complete functionality in case of a destructive earthquake. It was recommended to save copies of waveforms of significant earthquakes in the ORFEUS database. If destructive earthquakes are possible within the integrated networks, other more reliable means of transmitting data, like satellite data transmission, should be investigated. Recognising the possible contribution of CTBTO seismic stations in the network integration processes, the Workshop participants invited the CTBTO to release the collected seismic data to the scientific community with a minimal delay and to release the data in near real time in case of a destructive earthquake.
List of speakers invited to the September conferences.