A methodology for estimating the probable maximum loss (PML) of a water distribution network due to seismic induced liquefaction: A case in Iloilo City

• Main Author: Jarder, Samantha Louise N.
• Format: text
• Language: English
• Published: Animo Repository 2019
• Subjects: Underground pipelines—Earthquake effects—Philippines—Iloilo City; Hydraulic structures—Earthquake effects—Philippines—Iloilo City; Soil liquefaction—Philippines—Iloilo City; Earthquakes—Philippines; Water-supply—Philippines—Iloilo City; Water utilities—Philippines—Iloilo City; Civil Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/6333; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=13388&context=etd_masteral
• Institution: De La Salle University

Lifeline systems such as pipelines, power lines, and road networks are necessities in urban and suburban communities. They function to maintain the lives of the people. Among these lifeline systems, water pipelines are most crucial since water is necessary for everyday life. Since the Philippines is a seismically active region, these pipelines are exposed to geohazards such as liquefaction and landslides. Numerous studies had been conducted on the impacts of ground shaking to the buried pipelines; however, only a few consider liquefaction. In this paper, the probable maximum loss (PML) of a local water distribution network (WDN) in the Philippines due to earthquake-induced liquefaction is quantified. The peak ground velocities (PGV) 21 - 34 cm/s at the site for level 0 earthquake (50% in 50 years), 48 - 61 cm/s at level 2 (10% in 50 years), and 75 - 90cm/s at level 2 (2% in 50 years) earthquakes, respectively, are quantified using a probabilistic seismic hazard analysis (PSHA). Subsequently, the liquefaction severity index was determined and the results show that the liquefaction severity in the area, ranging from 23.50 - 78.63, 34.58 - 91.30 and 42.86 - 93.18 at Level 0, I and II Earthquake Hazard, respectively. The area is divided into grids (500m x 500m) where the damage spots and damage rate within each grid are estimated using a Poisson distribution. Subsequently, the probable loss was estimated and the PML of the WDN is around Php 78 million if a level 0 earthquake occurs, about Php 389 million for a level I and about Php 478 million for a level II earthquake. This pre-disaster planning through probable loss and PML is helpful to the WDN operator to prepare for seismic countermeasures or risk transfer such as insurance to reduce the loss.