Scientists at the University of the Philippines (UP) have reported that the gradual sinking of the ground, known as land subsidence, threatens not only Metro Manila but also other cities.
Jolly Joyce Sulapas, Audrei Anne Ybañez, and Dr. Alfredo Mahar Francisco Lagmay of the UP Diliman College of Science, along with Kayla Milcah Marasigan and Julian Marie Bernice Grageda of the UP Resilience Institute Nationwide Operational Assessment of Hazards, analyzed land subsidence in major Philippine cities from 2014 to 2020.
Their land subsidence analysis found that Bulacan in Greater Manila has the highest sinking rate at 109 millimeters per year.
“The high population density of cities makes the information more relevant to the public, as its impact on people is greater…Cities are also more vulnerable to land subsidence because the subsurface strata, or the rocks beneath the cities, are relatively younger,” Sulapas said.
The scientists reported that these sinking areas are mostly found in industrial and commercial zones since large and expansive manmade structures intensify subsidence.
They said such places must be monitored as subsidence increases flood risks, damages buildings and infrastructure, causes economic losses, and increases the vulnerability of residents in coastal communities to high tides and storm surges aggravated by climate change.
The research titled “Ground subsidence in major Philippine metropolitan cities from 2014 to 2020” was published in the International Journal of Applied Earth Observation and Geoinformation.
It cited excessive groundwater extraction, rapid urbanization, tectonic motion, and the natural compaction of sediments as factors that contribute to land subsidence worldwide. Moreover, rising sea levels due to climate change further worsens the issue.
