GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 Local Magnitude estimation for 10 years of Italian seismicity (2009-2018) based on new peak-to-peak amplitudes calculation on digital waveforms, and CLASS catalogue probabilistic locations R. Di Stefano, B. Castello, L. Chiaraluce, M. Michele, D. Latorre Istituto Nazionale di Geofisica e Vulcanologia, INGV Introduction The Italian National Seismic Network (RSN) progressively moved to Local Magnitude (M L ) as the predominant scale for the earthquakes monitoring system between 2005 and 2008, when RSN evolved to mostly 3-component sensors. Nevertheless, different methods of peak-to-peak maximum elongation measurement and M L event calculations have been used. This produced inhomogeneity of the M L data within earthquakes catalogs. In the present work, we applied a signal maximum Wood-Anderson amplitude measurement to digital waveforms from all the earthquakes in the CLASS catalog (Catalog of Absolute nonlinear 3D earthquakes Locations) of the Italian seismicity, for the period 2009-2018, creating a set of about 9Mln consistent amplitude values and related channel's M L for 270k events. To massively perform these tasks, automatic procedures are needed and thus we newly developed two separate python codes, PyAmp and PyML, designed on purpose: ● to apply an adaptive band-pass filter to the waveforms, based on the results of a signal to noise analysis ● to convert the signal to Wood-Anderson (WA) ● to define the maximum peak-to-peak elongation search window ● to find the maximum peak-to-peak elongation with two different methods ( lmag and swing ) ● to apply two different attenuation laws for channel M L  calculation, on all the three components (Z component is elaborated for possible back-in-time regression)