GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 1.1 58 Possible bias on earthquake locations and focal mechanisms due to the usage of the 1D velocity model (Lorenzo et al ., 2017) were investigated to assess the robustness of the results. Concluding, the Gargano Promontory seismicity result generated by a deep compressive stress regime with SHmax oriented NW-SE. Furthermore, the seismicity pattern analysis highlighted that 1) the entire involvement of the crust up to a depth of 40 km, 2) a kinematic heterogeneity in and around the Mattinata Fault shear zone due to preexisting multidirectional fractures (Fig. 2A and B) and 3) the presence of a low-angle seismogenic surface trending SW-NE and dipping SE-NW. References de Lorenzo, S., Michele, M., Emolo, A., and Tallarico, A.; 2017: A 1D P-wave velocity model of the Gargano promontory (southeastern Italy) . J. Seismol. 21, 909–919. doi: 10.1007/s10950-017-9643-7. Hardebeck, J.L., and Shearer, P.M.; 2002: A new method for determining first-motion focal mechanisms. Bull. Seismol. Soc. Am. 92, 2264–2276. doi: 10.1785/0120010200. Snoke, J.A., Munsey, J.W., Teague, A.C., and Bollinger, G.A.; 1984: A program for focal mechanism determi- nation by combined use of polarity and SV-P amplitude ratio data . Earthquake Notes 55, 1–15. Corresponding author: simona.miccolis@uniba.it Fig. 2