ISMD, a Web Portal for Real-Time Processing and Dissemination of INGV Strong-Motion Data

Abstract

In Italy, strong-motion monitoring started in the early 1970s, when the Rete Accelerometrica Nazionale (RAN, the Italian National Strong Motion Network; http://www.protezionecivile. gov.it/jcms/it/ran.wp;seeData and Resources for a complete listing of all websites listed in this article) was designed and installed by the Agenzia Nazionale per le NuoveTecnologie, l’Energia e lo Sviluppo Economico Sostenibile (ENEA) and ENEL (an Italian power company). The aim was to evaluate the seismic risk in connection with the construction of nuclear power plants. Since 1997, the RAN (Gorini et al.,2010) has been run by the Dipartimento della Protezione Civile (DPC). At present, the RAN includes about 500 digital strong-motion stations. The contribution of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) to Italian strong-motion monitoring started some years later. Through the 2004–2006 agreement between the INGV and the DPC (Strong-Motion Stations Project), the INGV began the phase of strong-motion monitoring (Augliera et al., 2010, 2011). Since 2006, a complete renewal of the (velocimetric) Rete Sismica Nazionale (RSN; Amato and Mele, 2008) was made by installing accelerometers to sites where broadband RSN velocimeters were already present. Altogether, the current∼150 high-dynamics digital strong-motion stations that cover the Italian territory constitute the INGV strong-motion network. The first channel chosen by the INGV to disseminate the recorded waveforms was through the European Integrated Data Archive (EIDA;http://eida.rm.ingv.it/;http://www.orfeus -eu.org/eida/eida.html), a web portal devoted to seismic data exchange that was developed in the framework of the Network of Research Infrastructures for European Seismology (NERIES) European project (www.neries-eu.org, Networking Activity 3 [NA3]). Since 2008, the INGV raw signals have been downloadable in the Standard for the Exchange of Earthquake Data (SEED) format from the continuous data archive of the INGV National Earthquake Centre (Centro Nazionale Terremoti, CNT). However, the EIDA web portal is devoted in particular to expert end users, and it provides raw data without further information about the waveform metadata and recording sites, which is fundamental for engineering purposes. The recorded RAN strong-motion data from 1972 to 2007 have been available to the scientific community only through specific data requests to the DPC. This changed in 2007, when the RAN data were also disseminated online through the ITalian ACcelerometric Archive (ITACA; Pacor et al., 2011), a static databank that arose in the framework of the S6 Seismological Project (Luzi et al., 2008), with the aim of periodically (usually every 1 year) distributing highquality corrected (i.e., manually processed by expert operators) data to the scientific community. Now, in the last release of ITACA version 2.0 (http://itaca.mi.ingv.it), users can find the RAN strong-motion corrected data up to the end of 2013. Even if the periodic publication of an updated version of ITACA provides new data for the scientific community, within the time span of two subsequent versions, significant earthquakes generally shake the Italian territory. Increasing demands for strong-motion data come from the scientific community soon after an important earthquake, in particular, and the INGV needed to homogeneously organize and disseminate the strongmotion data recorded by its own stations through a new dedicated channel. This motivated the co-operation of several INGV Working Groups to design and develop INGV Strong-Motion Data (ISMD), the first Italian real-time strong-motion web portal. The main scope of the ISMD is real-time archiving, processing, and distribution of strong-motion data recorded by the INGV and partner networks, complete with all of the necessary side information to correctly use the published data. In particular, the automatic system on which the new web portal is based can do the following: 1. check the quality of the raw accelerograms recorded by the INGV strong-motion network; 2. archive and process the data in real time to provide rapid estimations of the main strong-motion parameters of an earthquake; 3. disseminate high-quality strong-motion waveforms and related metadata in real time; 4. collect and distribute all of the available information about the recording sites (i.e., geological, morphological, geophysical); 5. check, update, and homogenize the information related to the INGV strong-motion stations currently installed throughout the entire Italian territory (e.g., coordinates, instrumentation); and 6. within minutes after an earthquake occurs, publish on the website (http://ismd.mi.ingv.it/) a real-time report of the event (e.g., event and waveform metadata, seismic response of recording sites, comparisons between observed and predicted data), jointly providing the binary–Seismic Analysis Code (SAC) uncorrected data (i.e., the raw SEED signals, converted into a new data format), the American Standard Code for Information Interchange (ASCII) corrected accelerograms (i.e., binary-SAC converted into ASCII format, and then processed), as well as the velocity and displacement time series and the related response spectra. The beta version of the ISMD was published during the May–June 2012 ML 5.9 Emilia (northern Italy) seismic sequence. At present it has archived about 23,500 three- component strong-motion records from∼360 Italian events that occurred from 1 January 2012 to the present update of 15 April 2014 with an ML≥3:0