ERMES. Monitoring of radon in geogas at the Gran Sasso National Laboratory

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1 ERMES. Monitoring of radon in geogas at the Gran Sasso National Laboratory G. De Luca a and W. Plastino b a Istituto Nazionale di Geofisica e Vulcanologia (INGV) Centro Nazionale Terremoti (CNT), Via di Vigna Murata, Rome, Italy b Department of Physics, University of Roma Tre, Via della Vasca Navale, 84 - Rome, Italy Abstract In the middle part of 2005, in the framework of the ERMES (Environmental Radioactivity Monitoring for Earth Sciences) research project, started the realization of a regional seismic network. The acquisition system and analysis data is located in the external building of the Gran Sasso National Laboratory (LNGS). A summary of this research activity is presented. 1 Introduction The ERMES research project includes a regional seismological monitoring. In the past few years, the Italian seismic monitoring system was greatly improved by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) thanks to the financial support of the Dipartimento di Protezione Civile nazionale (DPC) and, for southern Italy, of the Project ProSIS funded by the Italian Ministery for University and Research (MUR) [1]. The development of the National Network (Rete Sismica Nazionale, RSN - led actually about 260 seismic stations connected in real time to the acquisition centre in Rome, most of which equipped with broad band (40, 120, a few 240 s) or extended band (5 to 20 s) seismometers. Many stations are also equipped with a strong motion sensor. Transmission of the data is mostly based on satellite links or telephone lines. In addition, in Central Italy (Marche, Umbria, Tuscany and Abruzzi regions), INGV 171

Vasca Navale, 84 - Rome, Italy Abstract In the middle part of 2005, in the framework of the ERMES (Environmental Radioactivity Monitoring for Earth Sciences) research project, started the realization

2 incremented the number of real time and dial-up stations, in cooperation with the Service of Civil Protection of Marche Region, Osservatorio Bina (Perugia, Umbria), Fondazione Prato Ricerche (Prato, Tuscany) and INFN - Laboratori Nazionali del Gran Sasso (LNGS) - (L Aquila, Abruzzi), respectively. The dial-up stations operating today in the four regions are 52, in particular for Abruzzi region (Abruzzi regional network) we have 18 digital 3-components seismic stations with short period sensor (MARK L4C-3D - 1 Hz of natural frequency). The first station of this regional network was installed at the end of 2005 and the last in the April 2007, so about one seismic station per month. A detailed description of the network is reported on two web sites [2, 3] where both waveforms and bulletin data are published routinely. Moreover, it is necessary remember that in the past ( ) was running a regional seismic network [4, 5]. 2 Results The regional seismic network and the more important change of positions (arrow) of 3 stations that will happen in the 2008 are reported in Figure 1. The red triangles represent the RSN whereas the blue ones are the 18 regional seismic stations. As an example of the quality of the recorded data, we show only the vertical component waveforms of a magnitude 1.9 earthquake recorded by both the RSN and regional networks (Figure 2); in this figure it is possible to note also for such a small event a good signal to noise ratio up to more than 100 km distance and 27 triggered stations of both RSN and Regional Seismic Networks. In the figure 2 we show only the 17 stations; the nearest one at the earthquake is at the top of figure. The Figure 3 represents the seismicity of the area monitored from the regional network in the period January December The regional seismic network recorded 582 events in the period January December The magnitude range is from 0.7 ± 0.2 to 4.5 ± 0.1. The Figure 4 shows the efficiency of the network during the installation. In the Figure 5 we represent the two sections, latitude and longitude vs. depths of earthquakes. The seismicity is located in the 5-20 km layer. The depth seismicity (up to 30 km) is not real but are the events out of region. The residuals (in seconds) vs depth are represented in Figure 6. In the last two figures (Figs 7 and 8) we shown the selected events using cut offs in gaps, rms, depth errors, and minimum number of phase read. 3 Conclusions The Abruzzi regional seismic network has been completed on 2007 following the scheduled deadline. It recorded 582 events in the period January December 2007 with magnitude ranging from 0.7 ± 0.2 to 4.5 ± 0.1, and located in the 5-20 km layer. 172

The dial-up stations operating today in the four regions are 52, in particular for Abruzzi region (Abruzzi regional network) we have 18 digital 3-components seismic stations with short period sensor

3 4 Acknowledgments The authors are grateful to Prof. Eugenio Coccia for the his kind collaboration and support to ERMES research project. References [1] Amato A., L. Badiali, M. Cattaneo, A. Delladio, F. Doumaz and F. Mele, The real-time earthquake monitoring system in Italy. Gosciences, BRGM, 4, [2] Monachesi G and G. De Luca (eds.), 2007a. Le rilevazioni delle Reti Dial Up in Italia centrale. Istituto Nazionale di Geofisica e Vulcanologia, Dipartimento della Protezione Civile, Sistema Regionale di Protezione Civile e Sicurezza Locale della Regione Marche, Laboratori del Gran Sasso dell Istituto Nazionale di Fisica Nucleare, Osservatorio Sismico A. Bina, Istituto Geofisico Toscano. Roma. dun/index1home.htm [3] Monachesi G and G. De Luca (eds.), 2007b. Data base on line della Rete Sismometrica Abruzzese Istituto Nazionale di Geofisica e Vulcanologia, Dipartimento della Protezione Civile, Laboratori Nazionali del Gran Sasso dell Istituto Nazionale di Fisica Nucleare. L Aquila, [4] De Luca G., Scarpa R., Filippi L., Gorini A., Marcucci S., Marsan P., Milana G. and Zambonelli E. (2000). A detailed analysis of two seismic sequences in Abruzzo, Central Apennines, Italy. Journal of Seismology 4, [5] De Luca G., Del Pezzo E., Di Luccio F., Margheriti L., Milana G. and Scarpa R. (1998). Site response study in Abruzzo (Central Italy): underground array versus surface stations. Journal of Seismology 2,

Le rilevazioni delle Reti Dial Up in Italia centrale.

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Nearly real-time monitoring system of TABOO seismic network activity.

Nearly real-time monitoring system of TABOO seismic network activity. Marzorati S.* and TABOO working group * National Earthquake Centre, Ancona Istituto Nazionale di Geofisica e Vulcanologia Nearly real-time