Liquefaction potential map of Manila

• Main Author: Dungca, Jonathan R.
• Format: text
• Language: English
• Published: Animo Repository 1997
• Subjects: Soil liquefaction; Soil mechanics; Shear strength of soils; Civil Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/1855
• Institution: De La Salle University

A liquefaction potential map of the Manila Area is developed by combining the liquefaction susceptibility to liquefaction opportunity. Liquefaction susceptibility describes the resistance of soils to seismic loading and is determined using Seed's empirical relation between the standard penetration resistance and the cyclic stress ratio required to cause liquefaction. Liquefaction opportunity, on the other hand, refers to the intensity of ground shaking which can be determined from seismic hazard studies based on the historical earthquake events that hit the Manila Area. The information on liquefaction susceptibility and opportunity are combined using a probabilistic model accounting for uncertainty in the SPT blow count value and Seed's liquefaction susceptibility model. Results are presented as a map showing zones of different levels of risk. To compute for the probability of liquefaction on other sites within the Manila area, an equation was introduced based from the ratio of the normalized index of soil resistance to the probability of liquefaction. Over 200 boring logs from the City of Manila were examined showing the soil variability in the area. With the liquefaction potential hazard map, the city government can identify liquefaction potential areas and formulate city ordinances, code changes, or disaster mitigation requirements in the development of the said areas. Public and private property owners in the said areas will also be guided in the planning and development of infrastructures. The results indicate that the areas with the highest risk is identified in the vicinities of Binondo, Quiapo, Sta. Cruz, San Miguel, parts of Sampaloc, parts of Tondo, areas along the south bank of the Pasig River. The western part of Ermita extending southwards to the western part Malate are also under the high risk zone of liquefaction. The areas of Intramuros, eastern part of Ermita and Malate, and the parts of Paco have the moderate risk. Zones delineated with the lowest risk of liquefaction cover parts of