Benham Rise

The landform was presumably named after Admiral Andrew Ellicot Kennedy Benham (1832–1905) by American surveyors who were the probable discoverers of 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.[10]

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 Benham Plateau has similarly displaced the Philippine Fault System to the west.[11] After analyzing older models such as that of Pinet and Stephan (1989), scientists reconsidered their fault models. They thought that it is highly likely that the Benham Plateau is still displacing Central Luzon and the Philippine Fault System to the west, which may have had an impact in causing such a catastrophic earthquake. The 20-second to 50-second wave in the 1990 quake that developed a new east–west sub-fault was so strong that it terminated disastrously at 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. Additional data from international bathymetric surveys and an analysis of international research projects were collected to support the findings.[12]

Map of Luzon and the Benham Rise (labelled under the Philippine official name, "Philippine Rise")

Despite its proximity to the archipelago, the plateau was previously not included in the territory of the Philippines. On April 8, 2009, the Republic of the Philippines lodged a partial territorial waters claim with the United Nations Commission on the Limits of the Continental Shelf in relation to the continental shelf in the region of Benham Rise.[13] It was submitted as part of petition expanding the archipelago's baselines and exclusive economic zone through a law that also included other claims involving disputed territories of the Kalayaan Islands (Spratly Islands) and Scarborough Shoal. According to the government's claim, based on a set of guidelines by the commission on the Limits of the Continental Shelf, the area satisfies the 350-mile constraint line since the outer limits of the continental shelf are located landward of the constraint line, which is located 350 miles from the baselines where the measurement of the breadth of the territorial sea begins.[12]

The Congress of the Philippines enacted the bill of Senator Miriam Defensor Santiago, now known as Republic Act No. 9522, or the Archipelagic Baselines Law, which is the basis of the claim. According to the document the region is bounded by the Philippine Basin on the north and east, and by Luzon on the west and south. It asserted that, according to scientific data based on seismic, magnetic, other geological features, the Benham Rise is an extension of the Philippines' continental shelf. In summary, the baselines, the basis used for delineating the maritime territorial and jurisdictional zones (including the continental shelf), conform with the requirements of the UN Convention of the Law of the Sea (UNCLOS).[12] The claim is only a partial claim since the law that allows the Philippines to expand its territorial boundaries also includes islands in the South China Sea.

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, the first claim of the Philippines approved by an international body since the colonial era.[7][14][15][16]

After Chinese survey ships were spotted in the region in 2017, Philippine president Rodrigo Duterte suggested that the plateau be renamed to emphasize the Philippine's sovereignty over the area. Soon after, the Department of Foreign Affairs announced plans to come up with a new name.[17] In May 2017, the Philippine government officially adopted the name "Philippine Rise" for the feature[9] and designated the area as a "protected food supply exclusive zone" and prohibited mining and oil exploration in the Benham Plateau, angering China in the process. China maintained that the Philippines has no sovereign rights or sovereignty over the Benham Rise despite a UN-backed international ruling in 2012 that says otherwise.[18]

In January 2018, Filipino Congressman Gary Alejano revealed that the Department of Foreign Affairs had approved the Chinese Institute of Oceanology of the Chinese Academy of Sciences together with the Marine Science Institute of the University of the Philippines to perform a scientific survey of the Rise.[19]

In February, Duterte's agriculture secretary told media that Duterte has now ordered the halting of all foreign researches in the Philippines Rise, however, the research being conducted by the Chinese Academy of Sciences was already finished two days before the halt order.[20]

On February 12, 2018, the International Hydrographic Organization approved the names proposed by China for five features in the Benham Rise after China submitted to the organization its research findings on the area. The names given by China were all in Chinese, namely, Jinghao Seamount (some 70 nautical miles east of Cagayan), Tianbao Seamount (some 70 nautical miles east of Cagayan), Haidonquing Seamount (east at 190 nautical miles), Cuiqiao Hill, and Jujiu Seamount, the last two form the central peaks of the Benham Rise undersea geological province. The Chinese naming of the features met public protests in the Philippines.[21][22] The Presidential Palace announced that it objects and it shall not recognize the Chinese names of the features and it will appeal for its rejection in the International Hydrographic Organization. The Philippine government also said that their embassy in Beijing will coordinate with the Chinese regarding the issue.[23][24] A day later, the Palace announced that they intend to give Philippine names on the features of the Philippine Rise.[25] However, a few hours later, the presidential palace clarified that it has 'no problem' with the Chinese names in the Philippine Rise.[26]

On February 16, the Philippine government announced that they have sent military personnel into Cagayan Valley to guard the Rise.[27] Two days later, it was revealed that China intends to name a total of 142 features.[28] On February 26, the Department of Foreign Affairs stated during a Senate investigation that China actually surveyed the Rise in 2017 without any Philippine-issued permit, citing the lack of capability to detect illegal entry.[29]

The world's largest caldera with a diameter of 150 kilometers was recently discovered by Jenny Anne Baretto, a Filipina marine geophysicist. It was named after Apolaki, the mythical Filipino god of the sun and war.[30][31]