UP Geologists Report Subsidence Rates in Select PH Metropolitan Cities

Extreme damage running along the length of a road in Marilao, Bulacan is visible. (Photo credit: Sulapas et. al., 2024)


Wazzup Pilipinas!?


Excessive groundwater extraction, rapid urbanization, tectonic motion, and the natural compaction of sediments contribute to land subsidence worldwide. This issue is worsened by rising sea levels due to climate change, leading to frequent and severe flooding especially during high tides or typhoons, as well as local contexts of hazard management regulations.

Jolly Joyce Sulapas, Audrei Anne Ybañez, and Dr. Alfredo Mahar Francisco Lagmay of the University of the Philippines – Diliman College of Science (UPD-CS), along with Kayla Milcah Marasigan and Julian Marie Bernice Grageda of the UP Resilience Institute Nationwide Operational Assessment of Hazards (UPRI-NOAH) analyzed land subsidence in major Philippine cities from 2014 to 2020.

Their land subsidence analysis showed that Bulacan, which is located in Greater Manila, has the highest sinking rate at 109 millimeters (mm) per year. This was also the first study to examine land subsidence in other cities, with rates of 11 mm per year in Metro Cebu, 38 mm per year in Metro Davao, 9 mm per year in Metro Iloilo, and 29 mm per year in Legazpi City. “The high population density of cities makes the information more relevant to the public, as its impact on people is greater,” Sulapas said. “Cities are also more vulnerable to land subsidence because the subsurface strata, or the rocks beneath the cities, are relatively younger.”

These sinking areas are mostly found in industrial and commercial zones, where large and expansive man-made structures intensify subsidence. Monitoring these areas is crucial, as subsidence increases flood risks, damages buildings and infrastructure, and causes economic losses. This hazard also increases the vulnerability of residents in coastal communities to high tides and storm surges aggravated by climate change.

“It seems like industrial complexes require a lot of water to keep their operations running. The same can be said for residential areas,” Sulapas noted.



A reconnaissance fieldwork near the trace of the West Valley Fault showing cracks on the road with vertical displacements of 5-7 cm and an aperture of 12 cm (Photo credit: Sulapas et. al., 2024)

The study recommends sustainable groundwater use and improved water management practices. Sulapas mentioned that previous studies on land subsidence were recognized by the National Water Resources Board (NWRB). “The Board then identified zones where groundwater usage would be restricted,” she said.

“My co-authors were part of a previous study on subsidence in Metro Manila and surrounding provinces. This was during the year 2010,” Sulapas added. “So more than a decade later, what we wanted to do is to update the deformation data. In the case of the Greater Manila area, what happened after more than a decade?”

Moving forward, the team of researchers plans to incorporate additional data, such as groundwater extraction in the major Philippine metropolitan cities covered in their study, and correlate it with existing information. They also intend to continuously update their data to include the years 2021 to the present, collaborating with other researchers interested in contributing to the study over the next decade and beyond.

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, which publishes original papers that apply earth observation data to the inventory and management of natural resources and the environment.

Coral Triangle Nations Unite to Combat Marine Crisis, Set Bold 2025 Conservation Goals

Wazzup Pilipinas!?

The Coral Triangle spans 6 million square kilometers, hosting 76% of all known coral species, now threatened by overfishing, pollution, and climate change.

The region provides over 20% of the world’s seafood and strives to protect 30% of its marine areas by 2030, aligning with global conservation goals.
Six Coral Triangle countries including Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands, and Timor-Leste set bold 2025 conservation goals to address escalating threats to marine ecosystems, global food security and the livelihoods of over 130 million coastal residents since the population is growing.

Leaders from six Coral Triangle nations gathered in Dili this week, reaffirming their commitment to safeguarding the world's most biodiverse marine region. The 19th Senior Officials’ Meeting of the Coral Triangle Initiative on Coral Reefs, Fisheries, and Food Security (CTI-CFF) concluded with ambitious conservation targets for 2025, designed to address overfishing, climate change, and pollution that endanger marine ecosystems and threaten the livelihoods of 130 million coastal residents.

The Coral Triangle spans six million square kilometers across Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands and Timor-Leste, and harbors 76% of all known coral species, earning its reputation as the "Amazon of the Seas." It supplies over 20% of the world’s seafood and supports economies across Asia-Pacific. But the ecological powerhouse faces mounting pressures, with climate-induced coral bleaching, habitat destruction, and illegal, unreported, and unregulated (IUU) fishing threatening its delicate balance.

“This region is the beating heart of marine biodiversity and a cornerstone of global food security,” said H.E. Celestino da Cunha Barreto, Chair of the Committee of Senior Officials, Timor-Leste’s Director General of Aquaculture, Fisheries, and Aquatic Resources. “Our oceans sustain millions of livelihoods, but this is a shared global responsibility. We call on the international community to join us in protecting these vital resources.”

Delegates reviewed national and regional achievements under the Regional Plan of Action 2.0 (2021–2030) and finalized an ambitious agenda for 2025. This includes advancing collaboration through large scale area management, ensuring effective protection of ecologically important habitats, and reducing human impact on the marine ecosystem. All aim to maintain the livelihood for present and future.

Key 2025 priorities include advancing seascape collaboration in Sulu-Sulawesi, Bismarck-Solomon, and Lesser Sunda Seascapes, focusing on migratory species and research. CTI-CFF aims to enhance the COASTFISH framework by promoting livelihood studies, innovative fishing gear, sustainable practices, and combating IUU fishing. Partnerships with organizations like ATSEA, EU, SEAFDEC, ASEAN, and WCPFC will be strengthened.

 
The Coral Triangle nations also reaffirmed their leadership in achieving the global 30x30 target, which seeks to protect 30% of the world’s oceans by 2030. “Our commitment to 30x30 reflects not just a regional responsibility but a global imperative,” said Dr. Frank Keith Griffin, Executive Director of the CTI-CFF Regional Secretariat. “The Coral Triangle is a treasure for all humanity, and it demands bold, collaborative action.”

Efforts will also expand and improve the effectiveness of MPAs in the Coral Triangle, support manager networks, and contribute to global Sustainable Development Goal (SDG) 14 Life Below Water. CTI-CFF aims to achieve IUCN Green List Standards for its MPAs with GIZ SOMACORE support while fostering scientific collaboration and strengthened capacity of marine resource managers.

On the sidelines, CTI-CFF inked strategic partnerships with the Coral Triangle Center (CTC), the
WWF Coral Triangle Program and the Universidade Nacional Timor Lorosa’e. These agreements aim to bolster MPA management and the seascape approach, through capacity-building initiatives and regional knowledge exchanges.

Global partners, including GIZ SOMACORE, USAID, Conservation International, IUCN and WCS, reiterated their support for CTI-CFF’s mission. Yet, the Coral Triangle nations underscored the urgent need for broader collaboration, emphasizing the region’s critical role in sustaining global fisheries and biodiversity.

The outcomes of this pivotal meeting set the stage for the CTI-CFF 9th Ministerial Meeting, to be held on December 6, 2024. Ministers from the six Coral Triangle nations will convene to endorse strategic guidelines and further align regional efforts with global marine conservation goals.

Transforming Lives With Innovation: Revolutionizing Housing with Recycled Roof Plates in Indonesia

Seven Clean Seas combats the dangers of asbestos, linked to cancers and respiratory diseases, by replacing hazardous roofs in Batam, Indonesia, with durable, recycled plastic tiles made from 1,700 kg of ocean waste.

Seven Clean Seas, with philanthropic support, has successfully completed two home renovations in Indonesia’s Batam Island, replacing hazardous asbestos roofs with durable roof plates made from recycled plastic. This project not only transforms waste into life-saving infrastructure but also tackles critical public health issues linked to asbestos exposure, a material responsible for over 200,000 deaths annually according to the World Health Organization (WHO) and International Labour Organization (ILO).

The use of asbestos, which causes multiple cancers and chronic respiratory diseases, remains common in developing regions, where awareness and regulations lag behind. In 2024 alone, nearly 56,000 residents in Batam suffered from Acute Respiratory Tract Infections (ARI), highlighting the urgent need for safer housing alternatives. While over 50 WHO member states have banned asbestos, initiatives like this are vital in countries where its use persists. Beyond sustainable construction, it addresses critical gaps in awareness around asbestos hazards and environmental responsibility.

Innovative Housing for Disadvantaged Communities

Crafted from 250 shopping bags, approximately 1.5 kg in weight, each roof plate turns plastic waste into a sustainable housing solution. The completion of two houses - starting with the pilot on August 17, 2024 - has used 1,700 kg of plastic collected from the ocean, and repurposed waste into 1,186 roof tiles. Alongside replacing roofs, Seven Clean Seas invests in improving overall building structures, providing a secure home for families in need.

Empowering Through Education and Engagement

This initiative actively involves local residents, fostering awareness of how plastic waste can be repurposed for functional use. It also introduces the health dangers of asbestos, knowledge that has been critical in banning the material in much of the Western world. The combination of community education and hands-on participation ensures long-term benefits beyond the immediate physical improvements.

A Pathway to Sustainable Growth

Since 2018, Seven Clean Seas has built three ocean plastic recovery projects in some of Southeast Asia’s most polluted locations. To date, the organisation has recovered over 4,500 tons of ocean plastic and investments into innovative recycling and circularity solutions has remained a key focus. Now with the capability to transform ocean plastic into functional housing solutions, the goal of scaling up the positive impact globally is one step closer.

About Seven Clean Seas Pte. Ltd

Seven Clean Seas is an ocean impact organisation on a mission to become the world’s largest preventer of ocean plastics pollution. We are dedicated to tackling ocean plastic pollution through innovative, sustainably-financed solutions. Started in 2018 as a grassroots movement and officially founded in 2019 in Singapore, Seven Clean Seas works to remove plastic waste from the environment while creating social benefits through the provision of fair and direct employment in heavily polluted coastal communities.

This press release has also been published on VRITIMES