Francisco Macabulos retreated to Mount Arayat along with his men to avoid capture by the Spanish authorities in Tarlac, which used to be under the control of his forces. Several engagements would occur here afterwards until his surrender on January 15, 1898. World War II On Mount Arayat, Colonel Thorpe, an American guerrilla officer, was captured by Japanese forces on December 10, 1942. Mount Arayat would then be used as a hiding place for communist Filipino guerrillas called the Hukbalahap afterwards. Geography Mount Arayat stands in the middle of the flat Central Luzon Plain, consisting of rice paddies and a typical elevation of about 15 to 35 metres MSL. The mountain is topped by a circular volcanic crater about in diameter, much of which has collapsed on the western and part of the northern rim due to erosion. This has resulted in a breached crater which opens in a west-northwest direction. This area is the apparent source of a major debris-avalanche deposit that forms hummocky terrain beyond the west and northwest sides of the volcano. The summit stands on the northeast side of the breached crater, known as North Peak, while the Pinnacle Peak is located on the southeast crater rim. Post-collapse activity formed an andesitic lava dome known as White Rock in the collapse amphitheater. Eruptions There are no cultural records of historical eruptions. However, weak steaming is currently present in some of the heavily eroded vents on the North Western side of the summit. The ancient eruptions were said to have caused the formation of a Lava Dome on the Western Slopes of the mountain known as White Rock which makes a nice tourist destination and is usually a field trip destination for students of Pampanga State Agricultural University. The Arayat amphitheatre is said to have been caused by the summit's collapse on the western side but a much deeper crater is present on the eastern side, it was said that the mountain was once a volcanic island, until eruptions covered the surrounding area with soil, eruptions were said to be the possible cause of a theorized re-route of Pampanga River which is said to have once passed on the western side rather than eastern side where it currently moves. Geology Rock types are basalt and andesite. The only rocks reported to have been dated are 0.53 and 0.65 million-year-old basalts. These predate the crater collapse and formation