Development of seismic fragility curves for buried sewer pipelines and considerations of their applicability: case study on damage estimation of the sewer pipeline network in Lima, Peru

Abstract Seismic damage data for buried sewer pipelines affected by six earthquakes in Japan were analyzed to construct fragility curves considering pipe type, pipe diameter, liquefaction occurrence, and ground conditions. To verify the applicability of these fragility curves to regions outside Japan, they were applied to anticipated interplate mega-earthquake scenarios in Lima, Peru, a region of high seismic risk, to assess the seismic vulnerability of the sewer pipeline network. Under the specific Mw 8.55 earthquake scenario with rupture of the Ba-fault, the estimated length of damaged pipelines reached 94 km in CARABAYLLO and SAN MARTIN DE PORRES, and 86 km in VENTANILLA. Seven districts exhibited high damage ratios, with particularly severe damage exceeding 0.200 km/km in MI PERU, SANTA ROSA, and PUENTE PIEDRA. Considering ten interplate mega-earthquake scenarios, high-risk coastal drainage areas in CALLAO, CHORRILLOS, VILLA EL SALVADOR, and LURIN were identified and would not be detected by a single deterministic scenario. Sensitivity analyses showed that damage estimates are influenced by mesh resolution, representative seismic intensity values, proportionality factors, and microtopographic classifications. These findings highlight the importance of spatial resolution and detailed ground condition modeling when fragility curves are applied for seismic damage assessment of buried sewer pipelines.