GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 A promising method to estimate the rupture directivity effect but also the related source properties is based on the calculation of second seismic moments (Meng et al. 2020). The method has been successfully applied to small and moderate earthquakes (magnitude range 3.5 - 5.2) in Southern California, yielding stable results for 28 out of 41 events (Meng et al. 2020). In this study we estimate the rupture process and the source parameters of moderate events occurred during the 2016 - 2017 seismic sequence in central Italy, which is an excellent laboratory for normal fault earthquakes, particularly in the magnitude range of 3.4 and 6.5 (Colavitti et al. 2022). First, we applied the method based on the calculation of the second seismic moments using synthetic apparent source time functions calculated from a geometric source model obtained from a real event. We then applied both this methods (Fig 2) and conventional eGf deconvolution (Calderoni et al. 2015; 2017) separately to resolve the directivity of a moderate magnitude earthquake that occurred in central Italy in 2016 using data from RAN (Costa et al. 2022) and RSN network. Limitations and advantages are then discussed. References Abercrombie, Rachel E., Piero Poli, and Stephen Bannister. 2017. “Earthquake Directivity, Orientation, and Stress Drop Within the Subducting Plate at the Hikurangi Margin, New Zealand.” Journal of Geophysical Research: Solid Earth 122(12):10,176-10,188. doi: 10.1002/2017JB014935. Boatwright, J. 2007. The Persistence of Directivity in Small Earthquakes. Bulletin of the Seismological Society of Americ: 97 (6): 1850–1861. doi: 10.1785/0120050228 Calderoni, G., A. Rovelli, Y. Ben-Zion, and R. Di Giovambattista. 2015. “Along-Strike Rupture Directivity of Earthquakes of the 2009 L’Aquila, Central Italy, Seismic Sequence.” Geophysical Journal International 203(1):399–415. doi: 10.1093/gji/ggv275. Calderoni, Giovanna, Antonio Rovelli, and Rita Di Giovambattista. 2017. “Rupture Directivity of the Strongest 2016–2017 Central Italy Earthquakes.” Journal of Geophysical Research: Solid Earth 122(11):9118–31. doi: 10.1002/2017JB014118. Chen, Po, Thomas H. Jordan, and Li Zhao. 2010. “Resolving Fault Plane Ambiguity for Small Earthquakes.” Geophysical Journal International 181(1):493–501. doi: 10.1111/j.1365-246X.2010.04515.x. Colavitti, Leonardo, Giovanni Lanzano, Sara Sgobba, Francesca Pacor, and Franti š ek Gallovi č . 2022. “Empirical Evidence of Frequency-Dependent Directivity Effects From Small-To-Moderate Normal Fault Earthquakes in Central Italy.” Journal of Geophysical Research: Solid Earth 127(6). doi: 10.1029/2021JB023498. Costa, Giovanni, Piero Brondi, Laura Cataldi, Stefano Cirilli, Arianna Cuius, Deniz Ertuncay, Piero Falconer, Luisa Filippi, Simone Francesco Fornasari, Veronica Pazzi, and Philippe Turpaud. 2022. “Near-Real-Time Strong Motion Acquisition at National Scale and Automatic Analysis.” Sensors