Indonesia's Mount Ibu erupts, spews massive ash tower 5-14-2024 Mount Ibu (Indonesian: Gunung Ibu) is a stratovolcano at the north-west coast of Halmahera island, Indonesia. The summit is truncated and contains nested craters. The inner crater is 1 km (0.62 mi) wide and 400 m (1,312 ft) deep, while the outer is 1.2 km (0.75 mi) wide. A large parasitic cone is at the north-east of the summit and a smaller one at the south-west. The latter feeds a lava flow down the west flank. A group of maars are on the western and northern side of the volcano