# Investigation of Earthquake-Induced Pipe Damage in Liquefiable Soils
## 4 Evaluation of Pipeline Damage Caused by Earthquake in the Iskenderun Region
### Discussion of Results with Numerical Analysis of 3115 Station Data for Study Area 1  
The drinking water pipelines along the coastline in the Sarnseki zone in Study Area 1 suffered damage caused by liquefaction, while landslide-induced damage occurred in the spring water transmission pipelines on sloping terrain. The transmission lines of the Azganlik water treatment plant located near the border of the Sarnseki neighborhood were put into use in order to provide sufficient water supply to the region. The \(\O\) 1500 mm water treatment plant transmission line was inspected and no significant damage was detected; only a rerouting process [57,59] was carried out on this line to restore it to operational condition after the earthquake. Figure 13c depicts geophysical measurements conducted in the Sarnseki location and borehole ISK-113. Figure 14 presents the soil profile of borehole ISK-113 and geophysical survey (MASW-131) results. The geophysical survey showed that the shear wave velocity was 140 m/s in the top 4 m below the ground surface. Between depths of 4 m and 10 m, it went up to 210 m/s and then to 290 m/s below a 10 m depth. SPT-N\({}_{30}\) = 6-11 were obtained in this layer. Considering the geophysical survey results and SPT N values, the silty clay (alluvium) unit was classified as liquefiable (Figure 14). The alluvium is underlain by a conglomerate (Terrace Fr.) layer with a low shear wave velocity, which is not liquefiable (Vs = 290 m/s). In areas where coastal reclamation works are being carried out, an artificial fill layer consisting of gravel and boulders was placed on the natural ground surface. The 7 m thick layer of clayey gravel with boulders having a low shear wave velocity as revealed in borehole ISK-113 and geophysical survey MASW 131 represents the man-made fill. In order to evaluate the liquefaction potential of lithological units we applied the standard penetration test (SPT) and used simplified methods for the calculation of the factor of safety (Fs), the cyclical resistance ratio (CRR), and cyclical stress ratio (CSR). These methods were originally developed by [PERSON] and [PERSON] [61], and later updated by [PERSON] et al. [53,54,62], [PERSON] and [PERSON] [62], and [PERSON] et al. [54]. According to these, the variation in the safety factors obtained for the ISK-113 drilling with depth is given in Figure 14b. For local ground class ZE and a probability of exceedance of 10% in 50 years (with a return period of 475 years) along the Iskenderun coast (AFAD, [39]), a short-period design spectral acceleration coefficient of \(\S_{\text{DS}}\) = 0.977 was considered for calculating the safety factor (Table 3). At accelerometer station 3115, the peak ground acceleration (PGA) on the ground surface was measured as 287 cm/s\({}^{2}\). The coordinates of the station are (36.54634 and 36.16459), and it is located at an elevation of 180 m above sea level. Its distance to the epicenter of the Pazarcik earthquake is 113.57 km. The input seismic data () were initiated from a 1 m thick highly weathered rock layer, located at a 40 m depth at the base of the numerical model (Figure 15), referred to as a residual soil layer. At the base of station 3115, the shear wave velocity was measured as Vs30 = 424 m/s.