The recording stations of the Italian strong motion network: geological information and site classification

Abstract

One of the main objectives of the ITACA (ITalian ACcelerometric Archive) strong motion database, promoted by the Italian Department of Civil Protection, was to improve the characterization of the recording sites from a geological and geophysical point of view and to provide their seismic classification according to the seismic norms pertinent to Italy, namely the Eurocode 8 and the National Technical Norms for Constructions. A standard format to summarize the available information for the recording stations was first produced, in terms of a technical report dynamically linked to the database, i.e., some of the relevant information is automatically updated when the corresponding fields of the database are modified. Then, an important activity of collection, qualification and synthesis of available data was carried out, especially for stations that recorded the strongest earthquakes in Italy in the last 40 years, and for which a relevant number of studies have been published. In spite of this activity, among the more than 700 strong motion stations present in the ITACA database, only a limited number of them could be characterized by quantitative information on subsurface soil properties. For this reason, a dual seismic site classification criterion was implemented, either based on the standard V s,30 scheme, or, in the absence of such information, based on an expert opinion supported by shallow geology maps, mostly at 1:100,000 scale, and when available on the H/V ratios calculated on recordings. Owing 123 1780 Bull Earthquake Eng (2011Eng ( ) 9:1779Eng ( -1796 to the relevance in the Italian geographic and morphological context, a special care was also given to the topographic classification of stations, based on suitable criteria developed within a GIS environment.

Ground‐Motion Prediction Equations for Region‐Specific Probabilistic Seismic‐Hazard Analysis

“…Figure 2 shows the distributions of magnitude, distance, focal mechanisms, and Eurocode 8 (2004; EC8) site classes of the DBNI and the contribution of the 2012 Emilia sequence. The recording sites have been classified into three EC8 categories (A, B, and C), either on the basis of the average shear-wave velocity of the uppermost 30 m (V S30 ) or of available geological information (Di Capua et al, 2011). In the latter case, the site classes are indicated with an asterisk (i.e., A*, B*, and C*).…”

Complexity of the Mw 6.3 2009 L'Aquila (central Italy) earthquake: 2. Broadband strong motion modeling

“…In Table 1, the sites are classified according to the Eurocode 8 [ Comité Européen de Normalisation , 2004] and the Italian Building Code (http://www.cslp.it/cslp/index.php?option=com_docman&task=doc_download&gid=3255&Itemid=10) based on the shear wave velocity averaged over the top 30 m of the soil profile ‐ V s,30 . The EC8 class each station has been attributed on the basis of direct measure of V s,30 or on geological/geophysical information [ Di Capua , 2009; Di Capua et al , 2011].…”

Hybrid GMPEs for Region-Specific PSHA in Southern Italy

“…The metadata of both the events and stations were revised: the Italian Seismological Instrumental and Parametric Database catalog (http://iside.rm.ingv.it) was used to update the locations and magnitudes (i.e., Mw, ML), as well as the moment tensor solutions (i.e., strike, dip, rake) and information on the geometries of the seismic source. Recording sites are classified according to the EC8 seismic code [10] using, when available, the VS,30 value; otherwise the site category was defined based on the surface geological information [39].…”