Mjerenje radona u vodi radi predviđanja potresa u Sloveniji

Radon (222Rn) concentration in water of several thermal springs was measured with the aim of obtaining a correlation with the seismic activity of the region. Though a qualitative correlation was found for a spring with deep water circulation, we are far from being able to predict either the time or the place of an earthquake. An additional study with more relevant sampling sites and more frequent water analyses would be necessary to achieve this.Mjerili smo količinu radona (222Rn) u vodi iz više izvora radi utvrđivanja moguće korelacije sa seizmičkom aktivnosti u Sloveniji. Iako smo našli kvalitativnu korelaciju za jedan izvor s dubokim kruženjem vode, nismo još u mogućnosti predvidjeti mjesto ili vrijeme potresa. Za to su potrebna proširena mjerenja na više mjesta i sa češćim uzorkovanjem vode

Local magnitude scale in Slovenia

In the paper a calibration study of the local magnitude scale in Slovenia is presented. The Seismology and Geology Office of the Slovenian Environment Agency routinely reports the magnitudes MLV of the earthquakes recorded by the Slovenian seismic stations. The magnitudes are computed from the maximum vertical component of the ground velocity with the magnitude equation that was derived some thirty years ago by regression analysis of the magnitudes recorded by a Wood-Anderson seismograph in Trieste and a short period seismograph in Ljubljana. In the study the present single magnitude MLV equation is replaced by a general form of the Richter local magnitude MWA equation. The attenuation function and station-component corrections that compensate the local effects near seismic stations are determined from the synthetic Wood-Anderson seismograms of a large data set by iterative least-square method. The data set used consists of approximately 18 000 earthquakes during a period of 14 yr, each digitally recorded on up to 29 stations. The derived magnitude equation is used to make the final comparison between the new MWA magnitudes and the routinely calculated MLV magnitudes. The results show good overall accordance between both magnitude equations. The main advantage of the introduction of station-component corrections is the reduced uncertainty of the local magnitude that is assigned to a certain earthquake

Geodynamics at the Alps-Dinarides junction in Slovenia after geological, seismological and geodetic data

Central Europe Regional Geodynamic Project (CERGOP) in Slovenia includes GPS measurements on 5 sites. Within the first part of the project during years 1994-1997, measurements were performed on one site (Ljubljana), and during the CERGOP-2 extension in years 1999-2005 additional 4 sites were added (Božica, Malija, Snežnik and Mrzlica). However, till now measurements on the three sites only (Ljubljana, Božica and Malija) have been completed. Obtained data show similar sense and amount of horizontal displacements. They exhibit general northward movement of sites at the average velocity of 3 mm/yr. This is in accordance with results obtained from other sites of cirkum-Adriatic region, and it confirms the northward movement of the Adriatic microplate towards the “stable” Eurasian plate. In Slovenia, a northward oriented δ1 tensor have been also obtained from several tens of earthquake fault plane solution. Slight defferences in sense and velocity of displacements among particular sites could be explained by the influence of local structures. In Slovenia, they belong to the Periadriatic dextral shear zone, to the Dinaric dextral shear zone, and to the Transdanubian sinistral shear zone. However, the real dynamics of particular structures, among which some also express co-seismic creep, will be possible to determine only by GPS measurements over a denser network of sites

The Interreg IV Italia-Austria “SeismoSAT” project: connecting seismic data centers via satellite

Since 2002 OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) in Udine (Italy), the Zentralanstalt für Meteorologie und Geodynamik (ZAMG) in Vienna (Austria), and the Agencija Republike Slovenije za Okolje (ARSO) in Ljubljana (Slovenia) are using the Antelope software suite as the main tool for collecting, analyzing, archiving and exchanging seismic data in real time, initially in the framework of the EU Interreg IIIA project "Trans-national seismological networks in the South-Eastern Alps" (Bragato et al., 2004, 2010). The data exchange has proved to be effective and very useful in case of seismic events near the borders between Italy, Austria and Slovenia, where the poor single national seismic networks coverage precluded a correct localization, while the usage of common data from the integrated networks improves considerably the overall reliability of real time seismic monitoring of the area (Fig. 1). At the moment the data exchange between the seismic data centers relies on their internet connections: this however is not an ideal condition for civil protection purposes, since the reliability of standard internet connections is poor. For this reason in 2012 the Protezione Civile della Provincia Autonoma di Bolzano in Bolzano (PCBZ, Italy), OGS, ZAMG subsidiary in Tirol (ZAMG Tirol) and ARSO joined in the Interreg IV Italia-Austria Project "SeismoSAT" (Progetto SeismoSAT, 2012) aimed in connecting the seismic data centers in real time via satellite. ARSO does not belong to the Interreg Italia-Austria region: for this reason ARSO joined the SeismoSAT project as an "associated partner", which, according to Interreg rules can not be funded. ARSO participation in the project is therefore at the beginning limited in benefiting only indirectly from improvement in the robustness of the data exchange between the other data centers, while eventually fully taking part in the project if other sources of funding will be available. The project is in a preliminary phase: the general schema of the project, including first data bandwidth estimates and a possible architecture are here illustrated.Published57-601IT. Reti di monitoraggio e OsservazioniN/A or not JCRope

Trans-national earthquake early warning (EEW) in north-eastern Italy, Slovenia and Austria: first experience with PRESTo at the CE³RN network

The region of central and eastern Europe is an area characterised by a relatively high seismic risk. Since 2001, to monitor the seismicity of this area, the OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) in Italy, the Agencija Republike Slovenije za Okolje (ARSO) in Slovenia, the Zentralanstalt für Meteorologie und Geodynamik (ZAMG) in Austria, and the Università di Trieste (UniTS) have cooperated in real-time seismological data exchange. In 2014 OGS, ARSO, ZAMG and UniTS created a cooperative network named the Central and Eastern European Earthquake Research Network (CE3RN), and teamed up with the University of Naples Federico II, Italy, to implement an earthquake early warning system based on the existing networks. Since May 2014, the earthquake early warning system (EEWS) given by the integration of the PRESTo (PRobability and Evolutionary early warning SysTem) alert management platform and the CE3RN accelerometric stations has been under real-time testing in order to assess the system's performance. This work presents a preliminary analysis of the EEWS performance carried out by playing back real strong motion recordings for the 1976 Friuli earthquake (MW= 6.5). Then, the results of the first 6 months of real-time testing of the EEWS are presented and discussed

Seismogenic depth and seismic coupling estimation in the transition zone between Alps, Dinarides and Pannonian Basin for the new Slovenian seismic hazard model

Seismogenic depth and seismic coupling are important inputs into seismic hazard estimates. Although the importance of seismic coupling is often overlooked, it significantly impacts seismic hazard results. We present an estimation of upper and lower seismogenic depth and expected hypocentral depth and seismic coupling in the transition zone between the Alps, Dinarides and Pannonian Basin, characterized by a complex deformation pattern, highly variable crustal thickness, and moderate seismic hazard, supporting the development of the 2021 seismic hazard model of Slovenia. The hazard model was based on three seismic source models: area source model, fault source model and smoothed seismicity (point) source model. We estimated the lower seismogenic depth using seismological and geological data and compared them. The seismological estimate was based on two regional earthquake catalogues prepared for this study. In the area source model, estimates of lower seismogenic depth from seismological data are deeper or equal to the ones derived from geological data, except in one case. In the fault source model, we analysed each fault individually and chose seismological lower depth estimates in 12 among 89 faults as more representative. The seismogenic thickness for each individual fault source was determined for seismic coupling determination. The seismic coupling was assessed by two approaches, i.e. we chose the most trusted value from the literature, and the value determined for each fault individually by using the approach based on the updated regional fault and earthquake data sets. The final estimate of seismic coupling ranges from 0.77 to 0.38. We compared the tectonic moment rate based on long-term slip rate using different values of seismic coupling with the seismic moment rate obtained from the earthquake catalogue. The analysis is done for the whole area, as well as for the individual area zones. The analysis of N–S components of estimated slip for the largest faults in the area of west Slovenia shows that the regional geological and geodetic shortening rates are comparable. The total activity rate of three global seismic source models is compared, which gives up to a 10 % difference. Our results contribute to a better understanding of the seismic activity in the region. The presented approach for seismic coupling estimation can be applied in cases where the total slip rate is given instead of its seismic part and can be used at regional or national level. The approach is also suitable for the cross-border harmonization of the European seismic hazard modelling data.</p

The SHARE European Earthquake Catalogue (SHEEC) 1000–1899

In the frame of the European Commission project “Seismic Hazard Harmonization in Europe” (SHARE), aiming at harmonizing seismic hazard at a European scale, the compilation of a homogeneous, European parametric earthquake catalogue was planned. The goal was to be achieved by considering the most updated historical dataset and assessing homogenous magnitudes, with support from several institutions. This paper describes the SHARE European Earthquake Catalogue (SHEEC), which covers the time window 1000–1899. It strongly relies on the experience of the European Commission project “Network of Research Infrastructures for European Seismology” (NERIES), a module of which was dedicated to create the European “Archive of Historical Earthquake Data” (AHEAD) and to establish methodologies to homogenously derive earthquake parameters from macroseismic data. AHEAD has supplied the final earthquake list, obtained after sorting duplications out and eliminating many fake events; in addition, it supplied the most updated historical dataset. Macroseismic data points (MDPs) provided by AHEAD have been processed with updated, repeatable procedures, regionally calibrated against a set of recent, instrumental earthquakes, to obtain earthquake parameters. From the same data, a set of epicentral intensity-to-magnitude relations has been derived,with the aimof providing another set of homogeneous Mw estimates. Then, a strategy focussed on maximizing the homogeneity of the final epicentral location and Mw, has been adopted. Special care has been devoted also to supply location and Mw uncertainty. The paper focuses on the procedure adopted for the compilation of SHEEC and briefly comments on the achieved results