On November 27, 2023, the UP Resilience Institute was invited to attend the Expert Group Meeting on Asia-Pacific’s Sinking Cities. This meeting was organized by UNESCAP and UN-Habitat. The meeting was about the dangers of land subsidence on major cities, which results in them sinking. The objective of the Expert Group Meeting is to provide a better understanding of land subsidence and to provide solutions and share best practices.
UPRI Executive Director Mahar Lagmay presenting a talk titled “InSAR Assessment of Land Subsidence in Major Philippine Cities” during the Expert Group Meeting on Asia-Pacific’s Sinking Cities
The Executive Director of UPRI, Dr. Mahar Lagmay, was invited to give a presentation on the experiences of Manila in regards to land subsidence. It revealed that Manila has indeed experienced sinking into the ground, with the an average rate of 5.5cm change per year between 2003 and 2009. It was emphasized that areas of interest include Greater Manila, Metro Cebu, Metro Davao, Legazpi City, and iloIlo city, with Greater Manila experiencing the worst subsidence rate at 10cm a year. Excessive groundwater extraction is given as one of the leading causes of subsidence in Manila. Technical capacity needed for the city include monitoring ground deformation through the use of GPS, InSAR, and field data. The capacity to monitor groundwater extraction is also needed which would entail monitoring wells and reporting discharge from deep well users.
UPRI Executive Director Mahar Lagmay showing figures on Metro Manila’s land subsidence during the Expert Group Meeting on Asia-Pacific’s Sinking Cities