# Investigation of Earthquake-Induced Pipe Damage in Liquefiable Soils
## 4 Evaluation of Pipeline Damage Caused by Earthquake in the Iskenderun Region
In the coastal area, in the Sarneki neighborhood (Work Area 1), broken pipe joints due to liquefaction, a landslide which occurred along the water course near the spring, and rock fragments fallen onto the line caused significant damage, and the repairs were delayed due to difficult access. A total of 27 locations (Figure 12) along the transmission line which suffered damage were accessible and were fixed by welding [57; 59]. A 480 m long section of the pipeline on a cliff was repaired with difficulty by DSI and HATSU [57]. Although not all of the leaks in the landslide zone could be dealt with, water can still be obtained from this pipeline [57]. Figure 11: Ductile pipelines separated from their bells due to liquefaction on Atatürk Boulevard in (a) Yenisehir district; (b) Cay district, (c) Iskenderun City Center [57]. In 2018, a microzoning study was conducted by the Hatay Metropolitan Municipality in Iskenderrun, and the geological setting of the Iskenderun coastline was revealed (Figure 13a) [60]. In the microzonation survey, 400 boreholes were drilled to depths ranging from 6 m to 30 m. Of these, 128 encountered 15 m to 30 m thick alluvium along the coastline. In those boreholes, there is a topsoil layer, 0.50 m thick, underlain by sandy, silty clay, sandy clay gravel, and coarse gravel with large boulders (alluvial unit). In the areas identified as terraces (Trc/yellow areas), conglomerate layers were reached within 0.5 m below the surface. The Okcular Formation (Theo/open pink areas) consists of limestone units. Hatay ophiolites (Kha/green areas) comprise cumulates, diabase, pillow lavas, and volcanic sediments. The area not covered by the microzonation survey is indicated in red (Figure 13a). In this article, the behavior of buried pipelines under seismic effects was investigated using numerical analyses, considering the soil conditions in the areas referred to as Study Area 1 and Study Area 2. Seismic records obtained from stations 3115 and 3116 in Iskenderrun during the Kahramanmaras and Pazarcik earthquakes were utilized for this investigation. In Study Area 1, numerical analyses were conducted for buried steel pipes with diameters of \(\mathcal{O}\) 1500 mm and \(\mathcal{O}\) 2000 mm at burial depths of 1.2D, 1D, 1.2D, and 1.5D using data from accelerometer station 3115 (located on soil) and accelerometer station 3116 (located on rock). The analysis model initially considered a width equal to the thickness of the soil (H) (50 m), and later, in repeated analyses, it was expanded to approximately 3H (120 m) in width. In Study Area 2, the behavior of a steel pipe with a diameter of \(\mathcal{O}\) 1500 mm at a burial depth of 1.2D was investigated. The analysis model had a soil thickness (H) of 30 m and a width of approximately 3H (100 m). The analysis was conducted using data from station 3115 (located on soil). Figure 12: Ductile pipelines separated from their bells due to liquefaction and landslide in Sariseki district [57]. Figure 13: (**a**) Geology of the study areas [43]; (**b**) MASW Vs30 map for Study Area 2, Iskenderun Coastline, with ISK 259 borehole location and Section 1 [60]; (**c**) MASW Vs30 map for Study Area 1/ borehole of ISK-113 with location of MW-131 [60]; (**d**) Study Area 2—geological section of Iskenderun coastline—Section 1 boreholes from the Microzonation Survey Report [60].