Agrihan (also spelled Agrigan) is a stratovolcano which forms an island in the Northern Mariana Islands in the Pacific Ocean. The entire island is a massive volcano which rises over from the ocean floor, and is the fifth largest in the Marianas volcanic arc. At, its summit is the highest point in Micronesia. The volcano is topped by a large caldera, 1 x 2 km (0.6 x 1.2 mi) in size and about deep. The island was evacuated in 1990 due to the threat of volcanic activity, although in the end no eru… (More on Agrihan)