Hibok-Hibok has erupted four times in modern history. The first recorded eruption occurred in 1827 and a similar activity followed in 1862. Volcanic activity is currently monitored through solar-powered autonomous stations operated by the Hibok-Hibok Volcano Observatory under the
Philippine Institute of Volcanology and Seismology.
1871 to 1875 On February 16, 1871,
earthquakes and
subterranean rumblings began to be felt on the island, which increased in severity until April 30 when a
volcanic fissure opened up 400 yards southwest of the village of Catarman, on the northwest flank of Hibok-hibok Volcano. From the opening, lava was continuously ejected and poured into the sea for four years, destroying the town. At the same time, the vent built a cone now known as
Mt. Vulcan. In 1875, the
Challenger expedition visited the area, and described the mountain as a dome, about in height, without any crater, but still smoking and incandescent at the top. The portion of the town containing a cemetery has subsided into the sea and is now marked with a huge white cross off the coast. The settlement was relocated to where the present Catarman town center is now located. The remains of old Catarman, including the ruins of the ancient Spanish church, convent and a bell tower, are now called Gui-ob.
1897 to 1902 In 1897, Mt. Hibok-Hibok emitted white sulfurous steam that damaged villages on the island.
Solfataric activity continued up to 1902. In 1901, the volcano disappeared.
1948 to 1951 From 1948 to 1951, Mt. Hibok-Hibok constantly rumbled and smoked. There were also
landslides and earthquakes followed by dome building and
nuee ardente. The
Peléan eruption in 1948 from the Kanangkaan crater caused little damage and loss of life. The eruption of 1949, originating from Itum crater caused 79 deaths due to landslides. On the morning of December 4, 1951, the volcano erupted again. This time, however, it unleashed boiling lava, poisonous gases, and landslides enough to destroy nearly of land particularly in
Mambajao. All in all, over 3,000 people were killed. Before the eruption of Mt. Hibok-Hibok in 1951, the population of Camiguin had reached 69,000. After the eruption, the population was reduced to about 34,000 due to massive emigration. Volcanologists observed an eruption pattern during the 1948–1952 eruptions (a cycle of four phases) beginning with a short period of emission of steam from the crater and avalanches of volcanic materials, followed by explosions or steam blast with emission of heavy clouds of steam, ash and other fragmentary volcanic materials with a strong possibility of the development of pyroclastic flows. The third phase involves eruption of incandescent materials, emission of ash and steam in large amounts, formation of flows and occasional minor crater outbursts, and finally a decrease in steam and other ejecta from the crater. ==Monitoring==