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Mount Isarog
Isarog is an active stratovolcano located in the province of Camarines Sur, Philippines, on the island of Luzon. The mountain has active fumaroles and hot springs. It has an elevation of 2,000 m (6,600 ft) above mean sea level.
The broad isthmus between Lagonoy Gulf and San Miguel Bay is occupied by the isolated Isarog volcano.
The volcano has a 2,500 m-wide (8202 ft) crater that is breached to the east along a narrow valley drained by the Rangas River. A major debris avalanche deposit extends northwest to the coast and into San Miguel Bay.
The peak of the mountain marks the point where the borders of six municipalities and one city meet (listed in clockwise direction, starting north): Goa, Tigaon, Ocampo, Pili, Naga City, Tinambac and Calabanga.
Isarog Volcano was where local troops of the Philippine Army and Constabulary units and Bicolano guerrillas hid during the Japanese Occupation. In the 1970s, with the leadership of Romulo Jallores and his brother, they established the New People's Army in the Bicol region at the foot of this mountain.
Isarog Volcano is interpreted to have formed during the Pleistocene, as indicated by K-Ar dating of lava samples from the edifice, which yielded an age of 0.16 ± 0.12 Ma. The magmatic composition of Isarog Volcano is primarily andesitic, with minor dacitic components.
Isarog Volcano has been active since the Late Pleistocene. Around 30,000 years ago, it erupted, producing pyroclastic density currents (PDC). In the Holocene, a major sector collapse of its northwestern flank generated the Tinambac debris avalanche, which extended to San Miguel Bay and formed hummocky terrain across Calabanga, Tinambac, and Goa in Camarines Sur. Following the collapse, the volcano gradually rebuilt its edifice, though later dome growth introduced a new phase of hazards.
Block-and-ash flows originating from lava dome collapses have occurred during the Holocene, one of which has a calibrated radiocarbon date of about 3500 BCE. In 2020, a group of geologists from Partido State University discovered that Isarog also erupted around 2300 BCE after a charcoal overlain by thick block-and-ash flow deposits was found. The charcoal was sent to the United States for radiocarbon dating. This new information about the eruptive history of Isarog was presented at the 2020 Virtual GeoCon, a convention of geologists organized by the Geological Society of the Philippines.
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Mount Isarog
Isarog is an active stratovolcano located in the province of Camarines Sur, Philippines, on the island of Luzon. The mountain has active fumaroles and hot springs. It has an elevation of 2,000 m (6,600 ft) above mean sea level.
The broad isthmus between Lagonoy Gulf and San Miguel Bay is occupied by the isolated Isarog volcano.
The volcano has a 2,500 m-wide (8202 ft) crater that is breached to the east along a narrow valley drained by the Rangas River. A major debris avalanche deposit extends northwest to the coast and into San Miguel Bay.
The peak of the mountain marks the point where the borders of six municipalities and one city meet (listed in clockwise direction, starting north): Goa, Tigaon, Ocampo, Pili, Naga City, Tinambac and Calabanga.
Isarog Volcano was where local troops of the Philippine Army and Constabulary units and Bicolano guerrillas hid during the Japanese Occupation. In the 1970s, with the leadership of Romulo Jallores and his brother, they established the New People's Army in the Bicol region at the foot of this mountain.
Isarog Volcano is interpreted to have formed during the Pleistocene, as indicated by K-Ar dating of lava samples from the edifice, which yielded an age of 0.16 ± 0.12 Ma. The magmatic composition of Isarog Volcano is primarily andesitic, with minor dacitic components.
Isarog Volcano has been active since the Late Pleistocene. Around 30,000 years ago, it erupted, producing pyroclastic density currents (PDC). In the Holocene, a major sector collapse of its northwestern flank generated the Tinambac debris avalanche, which extended to San Miguel Bay and formed hummocky terrain across Calabanga, Tinambac, and Goa in Camarines Sur. Following the collapse, the volcano gradually rebuilt its edifice, though later dome growth introduced a new phase of hazards.
Block-and-ash flows originating from lava dome collapses have occurred during the Holocene, one of which has a calibrated radiocarbon date of about 3500 BCE. In 2020, a group of geologists from Partido State University discovered that Isarog also erupted around 2300 BCE after a charcoal overlain by thick block-and-ash flow deposits was found. The charcoal was sent to the United States for radiocarbon dating. This new information about the eruptive history of Isarog was presented at the 2020 Virtual GeoCon, a convention of geologists organized by the Geological Society of the Philippines.