Temporary seismological measurements in the Postojna cave system (Ob\u10dasne seizmi\u10dne meritve v postojnskem jamskem sistemu)

Karst caves are suitable places for seismological measurements because they are situated under the surface and often have lower seismic noise than locations on the surface. The idea to establish the first underground seismological station in Slovenia has led us to make preliminary seismic noise measurements in \u10crna Jama (part of the Postojna Cave System) in 2007. In search for further suitable stable places within the cave, we next performed seismic noise measurements, followed by a temporary accelerometer installation, near the highest point of the Velika Gora chamber in the first half of 2010. Since 7 May 2010, the seismic station is located inside the 9 m long artificial tunnel that was built for geophysical measurement purposes in Tartarus passage in 1931. From 27 January to 12 February 2010, the seismological station Velika Gora in Postojna Cave System (VGPJ) recorded 79 earthquakes with epicenters near Postojna. Records were especially important to determine the seismological characteristics of the MLV=3.7 Postojna earthquake (15 January 2010) aftershocks. The station in the Tartarus tunnel (TTPJ) operated from 7 May 2010 till 21 December 2010 and recorded more than hundred earthquakes of the sequence near Ilirska Bistrica that started on 15 September 2010, with two MLV=3.5 earthquakes and lasted till the end of the year 2010. The aim of this study is the installation of a permanent seismic station inside the Postojna Cave System and future real-time integration of the related seismological data within the Slovenian and Italian seismological networks

Improving Cross-Border Seismic Research: The Central and Eastern Europe Earthquake Research Network (CE3RN)

The complex tectonic setup of eastern Europe\u2014resulting in strong spatial variations of the local seismic hazard\u2014caused relevant institutions of neighboring countries to form a research cooperation to ease seismological research cooperations across borders. Here,we briefly introduce the original and new Central and Eastern Europe Earthquake Research Network (CE3RN) parties, with a synthesis of the common results achieved so far and an indication of possible future developments. Since the formal establishment of CE3RN, several common projects have been initiated, such as the SeismoSAT Project for the seismic data center connection over satellite and the Historical and Recent Earthquakes in Italy and Austria Project, both funded by the European Union INTERREG Italy\u2013Austria Program. The most recent 22 March 2020 earthquake near Zagreb, resulting in considerable damage in the capital of Croatia, demonstrated the importance of fast data exchange, thus facilitating reliable analysis of the earthquake. In addition, a recent breakdown of data lines in Austria demonstrated the usefulness of alternative data transmission via satellite

The AlpArray Seismic Network: A Large-Scale European Experiment to Image the Alpine Orogen

The AlpArray programme is a multinational, European consortium to advance our understanding of orogenesis and its relationship to mantle dynamics, plate reorganizations, surface processes and seismic hazard in the Alps-Apennines-Carpathians-Dinarides orogenic system. The AlpArray Seismic Network has been deployed with contributions from 36 institutions from 11 countries to map physical properties of the lithosphere and asthenosphere in 3D and thus to obtain new, high-resolution geophysical images of structures from the surface down to the base of the mantle transition zone. With over 600 broadband stations operated for 2 years, this seismic experiment is one of the largest simultaneously operated seismological networks in the academic domain, employing hexagonal coverage with station spacing at less than 52 km. This dense and regularly spaced experiment is made possible by the coordinated coeval deployment of temporary stations from numerous national pools, including ocean-bottom seismometers, which were funded by different national agencies. They combine with permanent networks, which also required the cooperation of many different operators. Together these stations ultimately fill coverage gaps. Following a short overview of previous large-scale seismological experiments in the Alpine region, we here present the goals, construction, deployment, characteristics and data management of the AlpArray Seismic Network, which will provide data that is expected to be unprecedented in quality to image the complex Alpine mountains at depth