# Investigation of Fault Effect on Blast-Induced Vibration
## 4 Discussion of the Results Based on Directions  
It may be stated that the analyzed rock mass presents a fairly uniform structure. This means the geology of the blasting sites is similar. The lithology of them is predominantly metamelange. However, regression analysis is undertaken using blast-induced vibration measurements according to two different directions. According to the location of the fault zone, two different directions were chosen for the study area. This factor adds uncertainties to blast vibration propagation. Vibration measurement stations located in the southwest are fallen behind the fault zone, which means there is not a fault zone between the blasting area and the geophone locations, while those in the northwest direction, the fault zone is between the blasting area and the geophone. The main purpose of the estimation models based on directions is to estimate the peak particle velocity value accurately before the blasting operation for ongoing production blasting, taking into account geological changes such as faults. On the basis of the PPV, SDs are often developed which make it possible to estimate the extent of damage to the excavation [30]. When evaluating the relationship between the scaled distance and resultant particle velocity based on directions, field factors are estimated for each direction. In Figure 11, cross-validation graphs are indicated for two different direction approaches in this study. The cross-validation coefficient shown as blue is 0.66 for southwest direction. On the other hand, the coefficient of the northwest direction shown as red is 0.72. Comparing the two regression lines, these two models estimate blast-induced vibration levels with different accuracy. Even though their damping parameters (\(\beta\)) are relatively similar, their field parameters (K) differ significantly. This shows that although there is no change in the general geological units, there is a change in the prediction model coefficients depending on the location of the fault zone. That is, if the measurements are made in one direction by considering the structures that will be affected by blast vibration, the estimation model to be obtained will not reflect the truth for the structures in different directions of the field. Geology and faulting of the area should be revealed by detailed research. According to the models of these two directions, the propagation distances of the blast-induced vibration will be different for the same number of explosives per delay. The graph of changing propagation (attenuation) distances, when evaluated according to different vibration values, is given below (Figure 11). The ground vibration attenuation connected with the fault zone was studied, and it was found that the PPV of ground vibration was increased by 66% at 5 mm/s when it travels in the northwest direction. In Figure 11, it is clearly seen that the estimated particle velocities produced by the northwest direction prediction model have different propagation distances compared to the southwest prediction model. Accordingly, the propagation (attenuation) distance of PPV between 3 and 7 mm/s is 1.5-2 times greater  
Figure 11: Estimated PPV values based on distance according to directional prediction models. than the propagation distance in the southwest direction. At velocities between 7 and 25 mm/s, this difference increases 2-2.5 times. At velocities between 25 and 50 mm/s, the difference in propagation distances becomes 2.5-3 times. For the sake of clarity, the propagation distances for the limit values in USBM using both prediction equations are given in Table 3.  
In Figure 11 and Table 3, it can be seen that the variation of the propagation distance depends on the direction. The propagation distances of the blast vibration velocities change directionally. However, according to the location and characteristics of the discontinuities, these variation rates vary.