Indigenous history

Mount Isarog has been the ancestral territory of the indigenous Isarog Agta people for thousands of years prior to the arrival of the Spanish. They were among the first inhabitants in the entire Philippines and are of Negrito origin. They are a group of Aeta people with a distinct language and heritage unique from others.^{[citation needed]}

Legal history

It was made a public land through the Proclamation No. 157 on March 28, 2015. Towns around it is classified as timberland forest with an area of 13,433 hectares (33,190 acres). ^{[citation needed]}

On August 17, 1935, General Frank Murphy established the Mt. Isarog Forest Reserve which reduced the size of the area to 10,112. But it was revoked by President Manuel L. Quezon when he signed Proclamation No. 293 titled "Establishment of Mt. Isarog as a National Park."^[11]

The Earth Summit of 1992 prompted the creation of the National Integrated Protected Area Programme. A five-year (1995-2001)^[12][13] intervention plan was enacted.^[14] On June 20, 2002, by virtue of Proclamation No. 214 signed by President Gloria Macapagal-Arroyo, Mt. Isarog became a protected area under the natural park.^[15]

Eruption history

Pyroclastic flows originating from lava dome collapses have occurred during the Holocene, one of which has a calibrated radiocarbon date of about 3,500 BCE. In 2020, a group of geologists from Partido State University discovered that Isarog also erupted around 4,300 years ago after a charcoal overlain by thick block-and-ash flow deposits was found.^[16][17] 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. Currently, Isarog vent displays gas seepages, warm springs, and steaming vents.^[18]

Seismic history

On 8 November 1915, frequent earthquakes were felt on and around Isarog volcano, with some occasional noises. Landslides occurred on the slopes of Isarog volcano. The seismic swarm repeated itself 2 or 3 times at long intervals until 10 January 1916. The volcano was thickly wooded, even inside of the crater, and nobody observed any fumaroles.^[8][7]

Isarog Agta Tribe

The Isarog Agta people live within the circumference of Mount Isarog, though only 5 of them still know their indigenous language. They are one of the original Negrito settlers in the entire Philippines. They belong to the Aeta people classification, but have distinct language and belief systems unique to their own culture and heritage.

In 2010, UNESCO released its 3rd world volume of Endangered Languages in the World, where 3 critically endangered languages were in the Philippines. One of these languages in the Isarog Agta language which has an estimated speaker of 5 people in the year 2000. The language was classified as Critically Endangered, meaning the youngest speakers are grandparents and older, and they speak the language partially and infrequently and hardly pass the language to their children and grandchildren anymore. If the remaining 150 people do not pass their native language to the next generation of Isarog Agta people, their indigenous language will be extinct within a period of 1 to 2 decades.

Endemic

Isarog Shrew rat (Rhynchomys isarogensis) was first discovered in 1988 in Mount Isarog. Although it has no direct economic value, its presence in Mount Isarog is a barometer of wealth and management of its natural resources. It is now listed as endangered in the Red Data Book of the International Union for Conservation of Nature.^[19]

Mount Isarog is included as a protected area, home to endemic rodents (Archboldomys luzonensis, Chrotomys gonzalesi and Rhynchomys isarogensis), other endemic mammals, and 15 bird species endemic to Luzon.

Isarog Cloud Frog was first described by scientists in 1997. In total, scientists have identified one and possibly three new frog species, 8 species of snakes, and 19 species of lizards.

Mount Isarog also has the rare Mount Isarog Forest Skink (Sphenomorphus knollmanae) that is endemic.^[19]