Iliwerung volcano forms a prominent south-facing peninsula on Lembata (Lomblen) Island and lies 80 km east of Flores. Its craters and lava domes have been built along N-S and NW-SE trend. In historical time both vents from the summit and submarine vents on the SE flank have been active.
Iliwerung volcano was constructed on the southern rim of the Lerek caldera. The present-day summit lava dome was built during an eruption in 1870. In 1948 the Iligripe lava dome grew on the eastern flank at 120 m altitude. In 1973-74, 3 temporary new islands were formed, when submarine eruptions began on the lower SE flank at a vent named Hobal.