GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 2.1 289 MACROSEISMIC INTENSITY TO GROUND MOTION EMPIRICAL RELATIONSHIPS FOR ITALY A.A. Gómez Capera 1 , M. Santulin 2 , M. D’Amico 1 , V. D’Amico 3 , M. Locati 1 , L. Luzi 1 , M. Massa 1 , R. Puglia 1 1 Istituto Nazionale di Geofisica e Vulcanologia, sezione di Milano, Italy 2 Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS, Trieste, Italy 3 Istituto Nazionale di Geofisica e Vulcanologia, sezione di Pisa, Italy Introduction. Empirical relationships between macroseismic intensity and different recorded ground motion parameters (GMP) are developed for the Italian territory in the framework of the project for the update of the national seismic hazard model (MPS16). The relationships are derived from a dataset of GMPs, as example peak ground acceleration (PGA), peak ground velocity (PGV) from ITACA 2.3 (Luzi et al. , 2017), and macroseismic intensities from DBMI15 (Locati et al. , 2016). In order to obtain the most complete dataset of available macroseismic intensity data, a series of publications with the results of macroseismic surveys on recent earthquakes in Central Italy (Galli et al., 2016; Azzaro et al ., 2016) not yet included in DBMI15 are also considered. The final dataset is being developed correlating strong motion stations and macroseismic intensity observations generally within 2-3 km from each other. The adopted functional form is linear and relates the logarithm of GMP and macroseismic intensity. The aim of this paper is to present progress of the updated of empirical relationships quoted. State-of-the-art. Previous literature scanning is proposed by Gomez Capera et al . (2007) and Cua et al . (2010). Current relationships for Italy are calibrated using a moderate number of Intensity-GMP pairs for high intensity levels (Faenza and Michelini, 2010; Faenza and Michelini, 2011). In Bilal and Askan (2014) and Tselentis and Danciu (2008), a mean GMP is assigned to each macroseismic intensity level to account for the uneven distribution of GMPs corresponding to a single macroseismic intensity class. In the framework of the 2014 DPC-INGV S2 project, relationships between GMP and macroseismic intensity for Italy were proposed (Gomez Capera et al ., 2015), using ITACA 2.0 (Luzi et al ., 2011) and DBMI11 (Locati et al ., 2011) as the preferred source of data. A dataset was obtained made of 118 pairs of macroseismic intensity-GMP from 53 Italian earthquakes in the time window 1976-2009, with Mw ranging from 3.9 to 6.9 and 3-4≤ I(MCS) ≤8-9. The relationships between macroseismic intensity and logarithm of GMP (PGA, PGV, SA at 0.3, 1.0, and 2.0 s) are linear and the GMP is the only independent variable. Data and methodology. In order to compile the dataset of paired macroseismic intensities and GMPs, we have applied the following criteria: • dataset used in the DPC-INGV S2 project (Gomez Capera et al ., 2015); • macroseismic and GMP updated database (DBMI15, Locati et al ., 2016; ITACA 2.3, Luzi et al ., 2017); • macroseismic intensity data for the 2016 Central Italy earthquakes (Galli et al., 2016; Azzaro et al ., 2016); • each selected strong-motion station in ITACA is linked to the closest macroseismic locality in DBMI using the web tool by Locati et al. (2016); it should be noted that an updated version of this tool is currently being worked on and will take advantage of the ASMI (Rovida et al. , 2017) web services (Locati et al. , 2017) that are providing access to macroseismic data in the latest version of DBMI, and the web services being developed for accessing data in ITACA; • macroseismic intensity observations and GMPs should have an interdistance lower than 6 km and similar geological/topographic conditions; • GMP is defined as the largest of the horizontal components; • GMP units are cm/s 2 for PGA; • to account for the uneven distribution of GMPs corresponding to a single macroseismic intensity, a mean value of GMP is assigned to each macroseismic intensity class.