1 SCALING OF EARTHQUAKE SOURCE PARAMETERS IN CORINTH RIFT (GREECE) FROM SPECTRAL ANALYSIS: INFLUENCE OF ATTENUATION AND SITE EFFECTS Emanuela MATRULLO 1 , Claudio SATRIANO 2 , Anais IBOURICHENE 3 , Hélène LYON- CAEN 4 , Pascal BERNARD 5 , Anne DESCHAMPS 6 The issue of earthquake source scaling continues to draw considerable debate within the seismological community: observation supporting and refuting that systematic differences between the source processes of small and large earthquakes are still discussed. This motivates the study of how source parameters, such as seismic moment and corner frequency scale over a wide range of magnitudes. In source studies, removing the attenuation term is fundamental in order to study self- similarity of the source spectrum; this can be done by inverting for the theoretical Q, using empirical Green’s functions (EGFs) or multiple EGFs to remove path and site effects, measuring spectral parameters from the coda, or using κ r to correct for high-frequency attenuation (e.g., Abercrombie, 1995; Mayeda and Walter, 1996; Hough, 1999; Oth et al., 2011; Lancieri et al., 2012; Ktenidou et al., 2014). On the other hand the estimation of the heterogeneous distribution of seismic attenuation from the dispersion of amplitude with frequency is important for the characterization of rock and fluid properties, e.g., saturation, porosity, permeability, and viscosity, because attenuation is more sensitive than velocity to some of these properties. It is also very important for seismic hazard assessment. The installation of high-resolution digital seismic networks in the last decades has led to a large development of methodologies allowing investigating the proprieties of earthquake source parameters at very small scales. These outcomes will enable a clearer understanding of the earthquakes process similarity over a broad magnitude range and to have detailed information about swarm activity (earthquakes source dimension and interaction). The Corinth rift is in a rapidly asymmetric opening structure (6 to 16 mm/yr from east to west). Its southern coast is bordered by a series of large normal faults and the seismic activity is important. The area is one of the best-instrumented fault systems in Europe: since year 2000, dense array monitoring (seismology, GPS, strain-meters) has produced an exceptional dataset. Today a dense seismic network that consists of 21 recording stations (9 equipped with broadband seismometers and 12 with short period ones) monitors the western part of the rift. The average distance between stations is about 5 km and the minimum local magnitude threshold for the event detection and location is about 1. The overall seismological data set consists of about 100,000 events (2000-2013), and covers seven orders of magnitude of seismic moment Mo (10 10 – 10 17 Nm). Figure 1 shows as example of a selection of 7377 automatically located earthquakes (133191 traces) that occurred in 2010 and 2011 with at least 6 P-wave and 2 S-arrival time picking, max 1 Post-Doc Laboratoire de Géologie, CNRS, Ecole Normale Superieure, Paris (France) matrullo@geologie.ens.fr 2 Research fellow, Institut de Physique du Globe de Paris, Paris (France) satriano@ipgp.fr 3 Master student Laboratoire de Géologie, École Normale Superieure, Paris (France) aibourichene@live.fr 4 Senior scientist, CNRS, Laboratoire de Géologie, École Normale Superieure, Paris (France) Helene.Lyon- Caen@ens.fr 5 Senior scientist, Istitut de Physique du Globe de Paris, Paris (France) bernard@ipgp.fr 6 Senior scientist, Géoazur, Université de Nice Sophia Antipolis/CNRS, Sophia Antipolis, France, deschamps@geoazur.unice.fr