Benham Rise

About

The Benham Rise, formally designated as Philippine Rise (Filipino: Talampas ng Pilipinas) by the Philippine government, is an extinct volcanic ridge located in the Philippine Sea approximately 250 kilometers (160 mi) east of the northern coastline of Dinapigue, Isabela. The feature has long been known to the people of Catanduanes as Kalipung-awan, which literally means “loneliness from an isolated place”, since the precolonial era. Under the Philippine Sea lie a number of basins including the West Philippine Basin, inside of which is located the Central Basin Fault (CBF). Philippine Rise is located in the CBF and its geologic basement is probably a micro-continent. Several scientific surveys have been made on the feature to study its nature and its impact on tectonic subduction, including one about its effects on the 1990 Luzon earthquake. The Philippines claimed this feature as part of its continental shelf in a claim filed with the United Nations Commission on the Limits of the Continental Shelf on April 8, 2009, and which was approved under the United Nations Convention on the Law of the Sea (UNCLOS) in 2012. The rise is designated as a “protected food supply exclusive zone” by the Philippine government since May 2017. Mining and oil exploration are banned in the area as it is protected. The feature was renamed as "Philippine Rise" by Executive Order No. 25 on May 16, 2017 and by The Philippine Maritime Zones Act on November 8, 2024.

The landform was presumably named after Admiral Andrew Ellicot Kennedy Benham (1832–1905) by American surveyors who probably studied the geological feature. He was a United States Navy officer, who served with both the South Atlantic and West Gulf Blockading Squadrons during the American Civil War.

There has been speculation in the scientific community about the nature of the landform. Following the major July 16, 1990 Luzon earthquake, scientists reconsidered their fault models and decided it likely that Philippine Plateau has similarly displaced the Philippine Fault System to the west. After analyzing older models such as that of Pinet and Stephan (1989), scientists reconsidered their fault models. They thought it highly likely that the Philippine Plateau is still displacing the Central Luzon and the Philippine Fault System to the west, which may have been a factor in such a catastrophic earthquake. The 20- to 50-second wave of the 1990 quake that developed a new east–west sub-fault was so strong that it terminated disastrously in the city of Baguio in Benguet, Cordillera. Several scientific surveys, conducted between 2004 and 2008, collected hydrographic data that determined the morphology of the seabed in the region.

Despite its proximity to the archipelago, the portion of the undersea feature beyond the 200 nautical mile Exclusive Economic Zone was previously not included in charted territory of the country. On April 8, 2009, the Republic of the Philippines lodged a partial submission with the United Nations Commission on the Limits of the Continental Shelf to claim this portion as part of the country's extended continental shelf in relation to the continental shelf in the region of the Philippine Rise. It was submitted following the legislation of Republic Act No 9522 on March 10, 2009, which defined the country's archipelagic baselines. Congress then enacted the bill of Senator Miriam Defensor Santiago, now known as Republic Act No. 9522, or the Archipelagic Baselines Law, as the basis of the claim. It asserted that, according to scientific data based on seismic, magnetic, other geological features, the Philippine Rise is an extension of the Philippines’ continental shelf. The Philippines filed its claim for Benham Rise in 2008 in compliance with the requirements of the United Nations Convention on the Law of the Seas. The UN officially approved the claim in April 2012 under the administration of President Benigno Aquino III. It was the first claim of the Philippines approved by an international body since the colonial era. After Chinese survey ships were spotted in the region in 2017, President Rodrigo Duterte suggested the plateau be renamed to emphasize Philippine sovereignty over the area. Soon after, the Department of Foreign Affairs announced plans for a new name, and in May 2017, the government officially adopted the name “Philippine Rise” for the feature designating the area as a “protected food supply exclusive zone” and banning mining and oil exploration. This angered China, which maintained the Philippines has no sovereign rights or sovereignty over the Philippine Rise, despite the UN-backed 2012 international ruling saying otherwise.

Adapted from Wikipedia (CC BY-SA). Photography via Wikimedia Commons.