Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

322 PATA Days 2024 to Falth’s 5 mm predicted at 200 m, the Moss equations predicted displacements of 370 mm at the same distance (7400% larger). Falth et al. (2010) predicted shears on target fractures at distances of 200, 600, 1000, and 1500 m from a hypothetical activated fault dipping 70° and magnitudes of M5.5, 6.2, and 7.5. We calculated the same displacements using the FDHI database and empirical equation of Nurminen. Again, the Nurminen displacement curve for an M5.5 event predicted displacements >200% of Falth’s. For an M6.2 event, a similar ratio was observed. For an M7.5 event, Nurminen’s displacements were 450% to 800% of Falth’s. Fig. 2: Comparison of induced fracture displacements (d) on the FW predicted by Fälth et al. (2015, upper left); for fractures at 200 m distance (solid black), 400 m (dashed black) and 600 m (dotted black). Colored symbols show median values of (d) predicted by Nurminen et al. (2020) for earthquakes of the same magnitude, Davg, and Dmax (”d” values are colored symbols on the 50%-ile line; shapes represent different scenarios, colors correspond to the three distances at lower left). Summary of PFC (Particle Flow Code) displacements versus Empirical Displacements For the case of local area, low-angle faults (like ZFMA2, M5.76, D=0.47 m), empirical fracture displacement values are all larger than the Yoon values. Yoon’s median displacement values at a distance of 1900mwas 1 to 4mm. For the same input variables usingNurminen’s 2020 equation, median (50%-ile) displacements at 1900 m distance were 9.1mm (+13mm/-5.3mm). We also ran two simulations (same magnitude and distances) with the new Moss et al. (2022) equation for distributed displacements during reverse ruptures, which predicts d/Dmax at various distances. Compared to Yoons’s (median?) 5 mm predicted at 1900 m, the Moss equations predicted (95%-ile) displacements of 166 mm at the same distance, roughly three times the Nurminen 95%-ile value. Yoon and Zang (2019) predicted shears on other named Deformation Zones at distances of 600 to 1770 m from a hypothetical M5.5 event on ZFMA3, with D=0.32 m. Their “d” values ranged from 20 to 80 mm (Table 1). Our values from empirical equations ranged from 9 to 14 mm (Nurminen) and 117 to 158 mm (Moss), thus bracketing the Yoon values.