GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.3 ______ ___ GNGTS 2023 Fig 1. A) CFS map for seismicity in Southern California, SCEDC catalog, 1985 − 2021, M L ≥ 1.0. Seismicity occurs, on average, at slightly positive CFS values. (B) Correlation ρ between CFS and seismicity in the Ridgecrest District, California, between 1985 and 2021. The scatter plot is realized by considering earthquakes happened at latitude 35.2° − 36.4° N, longitude 117.0° − 118.2° W and -2 − 20 km deep, ML ≥ 1.0. A preseismic phase featured by an increase of the correlation is detected before the Ridgecrest seismic sequence, mainshock 6/7/2019, M w 7.1. The red line is a weighted smoothing spline. Two horizontal colour bars above the scatterplot show nested “seismic cycles” whose phases are highlighted by different colours (green for the post-seismic phase, the interseismic one is in yellow and the coseismic phase is in red). (C) Histogram of energy nucleated by earthquakes with M L ≥ 1.0 (blue bars) and plot of the number of recorded seismic events (red line) After Zaccagnino et al., 2022a.