Iwaki (ēwä`kē), city (1990 pop. 355,812), Fukushima prefecture, NE Honshu, Japan, on the Pacific Ocean. Once a major coal-mining center, Iwaki now relies on other products such as chemicals, petrochemicals, electronics, and lumber. The extensive present-day city was formed in 1966 from the merger of five cities and nine other municipalities. A number of museums and an aquarium are there. Coastal areas of Iwaki were devastated by the tsunami that followed the 2011 NE Honshu earthquake.