Ragang
Ragang, commonly referred to as Mt. Piapayungan, is a stratovolcano situated in the regions of Lanao del Sur and Cotabato. The local people of Lanao del Sur, Maguindanao, and some parts of North Cotabato also call it the blue mountain. Students from Mindanao State University in Marawi, however, prefer to call the mountain as the “Sleeping Lady” due to its resemblance to the form of a reclining woman when observed from their campus. In the notes of Miguel Saderra Masó concerning the Ragang Volcano and a great earthquake in South Mindanao, the name “Palao Ragang” appears. This term translates to “the mountain where smoke or fire rises,” (Masó, 1917) indicative of historical activity of the volcano of which little was known prior to its eruption in 1916.
Standing at an impressive height of 2,890 meters, Ragang ranks as the fifth(?) highest peak in the Philippines (Lasco, 2016). It has a basal area of 334.6 square kilometers, a basal width of 38 kilometers, and a total volume of 265 square kilometers. Ragang has three summits and a deep crater with a 2-mile-long (3 km) lava flow that originated in the crater and traveled to the southeast (Volcano World, 2025). Its cone has two deep breaches in the north and a large amphitheater facing south. Not much is known about this amphitheater nor of the entire volcano as it is largely unmapped. Ragang Volcano forms part of the Central Mindanao Volcanic arc, which features several young volcanic cones stretching southeast of Lake Lanao (Global Volcanism Program, 2013c).
Eruptions of Ragang
Mt. Ragang is the most active volcano in Mindanao with 8 recorded eruptions and one that is uncertain (GVP, 2024). All eruptions of Ragang have a Volcanic Explosivity Index (VEI) of 2 on a scale from 1 to 8, which mean that its historical eruptions have not been that massive. For comparison, Pinatubo exploded cataclysmically in 1991 with a VEI of 6. The earliest recorded eruption of the blue mountain was in 1756 and was followed by eruptions in 1834, 1840, 1856, 1858, 1871, 1873, and 1916. Its last explosive activity took place in July 1916 and lasted for about 15 days. Volcanic deposits found along the coast of Illana Bay, roughly 50 kilometers east of Ragang, imply that significant and relatively recent eruptions have occurred (Masó, 1917).
After its eruption in 1916 Lieutenant W.F. Donnelly, part of a constabulary patrol, reported ash and vapors that devastated vegetation within a 3.5-kilometer radius. Intrigued by this discovery, Colonel P.E. Traub, the Chief of the District, organized an expedition to investigate the volcano’s activity further. The team noted three peaks surrounding an extinct crater, where an ancient, jagged lava flow extended for approximately 3 kilometers. Newer lava flows and tephra were scattered around the cones and crater, varying in size from boulders and bombs to fine ash. The eruption’s likely source was identified as a highly active fissure measuring about thirty meters in length and five meters wide and deep (Masó, 1917).
Other Names: Piapayungan, Blue Mountain (local), Palao Ragang
Latitude and Longitude: 7.70997 124.53487
Region: Bangsamoro Autonomous Region in Muslim Mindanao (BARMM)
Tectonic Setting: Subduction (Cotabato Trench)
Volcanic Arc/Belt: Cotabato Arc
Volcanic Region/Field: North Mindanao Volcanic Region
Volcano Type: Stratovolcano
Last Known Eruption: July 1916
Morphometry Type: Breached edifice, Massif
Highest Peak (masl): 2640
Coordinates of Highest Peak: 7.70997 124.53487
Prominence (m): –
Basal Area (km2): 334.6
Basal Width (km): 38
Volume (km3): 265
How to cite this page:
UPRI (2025) Ragang: Volcanoes of the Philippines (NOAH Open File Reports). Distributed by the University of the Philippines Resilience Institute, compiled by A.M.F. Lagmay. ISSN 2362 7409.
References:
Commission on Volcanology (COMVOL), 1981. Catalogue of Philippine volcanoes and solfataric areas. Philippine Commission on Volcanology, compiled by B. Yambao and G.A. Andal, 87 p.
Corpuz, E. S. G. (1992). Petrology and geochemistry of the central Mindanao volcanic arc, southern Philippines. Thesis
Corpuz, E. S. G. (1992). Petrology and geochemistry of the central Mindano volanic arc, southern Philippines. Thesis
Global Volcanism Program, 2024. Ragang (321050) in [Database] Volcanoes of the World (v. 5.2.5; 23 Dec 2024). Distributed by Smithsonian Institution, compiled by Venzke, E. https://doi.org/10.5479/si.GVP.VOTW5-2024.5.2
IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth’s Interior.
Lagmay, A. M. A., & Baldago, M. C. B. (2020). A timeline of Mindanao disasters. University of the Philippines Press.
Lasco, G., 2016. The 10 highest mountains in the Philippines (2016 update). URL //http://www.pinoymountaineer.com/2016/01/ the-10-highest-mountains-in-the-philippines-2016-update.html.
Masó, M. S., 1917. Notes concerning the Ragang Volcano and a great earthquake in South Mindanao. Bulletin of the Seismological Society of America, 7, 3, 119–121.
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PHIVOLCS, 2018-. Volcanoes of the Philippines. https://www.phivolcs.dost.gov.ph/index.php/volcano-hazard/volcanoes-of-the-philippines.
PHIVOLCS-LAVA Eruption History. https://wovodat.phivolcs.dost.gov.ph/volcano/erupt-history
Sajona F G, Bellon H, Maury R C, Pubellier M, Cotten J, Rangin C, 1994. Magmatic response to abrupt changes in geodynamic settings: Pliocene-Quaternary calc-alkaline and Nb-enriched lavas from Mindanao, Philippines. Tectonophysics, 237: 47-72.
Sajona F G, Bellon H, Maury R C, Pubellier M, Querbral R D, Cotten J, Bayon F E, Pagado E, Pematian P, 1997. Tertiary and Quaternary magmatism in Mindanao and Leyte (Philippines): geochronology, geochemistry and tectonic setting. J Asian Earth Sci, 15: 121-153.