GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 2.2 423 1-D model in which parameters are constant within each layer. In the latter case, the depth h of the seismic discontinuity is immediately derived from the free-surface resonance equation h=V/ (4f 0 ), where V is the seismic wave velocity of the upper layer and f 0 is the resonance frequency which appears as a peak in the H/V curve. Another important parameter is the vulnerability index (Kg) which can be determined using the empirical relation Kg=(A f0 ) 2 /f 0 , in which A f0 is the amplitude at the fundamental frequency, which determines the damage level due to local site effects (Nakamura, 1996). It may be considered for predicting the potential for soil liquefaction. This value, in fact, is clearly site-specific and value might be useful in demarcating weak regions, which are susceptible to liquefaction (Huang and Tseng, 2002; Beroya et al. , 2009). Tab. 1 - HVSR stations: Coordinates, peaks frequency and vulnerability index. NAME COORDINATE RESONANCE FREQUENCY VULNERABILITY INDEX STATION 1 E 72.5747455 17.74 0.48 N 3.0442160 STATION 2 E 72.5749796 18.07 0.47 N 3.0442796 STATION 3 E 72.5751135 17.42 0.27 N 3.0438757 STATION 4 E 72.5746621 19.84 0.28 N 3.0437169 STATION 5 E 72.5744101 21.32 0.18 N 3.0437184 STATION 6 E 72.5741537 24 0.13 N 3.0436779 STATION 7 E 72.5736108 14.68 0.13 N 3.0435533 STATION 8 E 72.5735079 21.95 0.18 N 3.0435640 STATION 9 E 72.5739085 22.23 0.22 N 3.0437146 STATION 10 E 72.5737335 23.95 0.23 N 3.0437007 STATION 11 E 72.5743638 19.48 0.29 N 3.0440285 STATION 12 E 72.5745511 11.98 0.54 N 3.0440540 STATION 13 E 72.5757599 2.27 6.83 N 3.0448697 STATION 15 E 72.5758687 1.73 5.91 N 3.0447355 STATION 16 E 72.5757227 8.4 4.80 N 3.0446317 STATION 17 E 72.5755179 11.31 3.15 N 3.0443865 STATION 18 E 72.5753558 2.66 11.04 N 3.0445186 STATION 19 E 72.5752942 1.54 26.68 N 3.0440625 STATION 20 E 72.965673 9.07 1.23 N 3.0803232