Eruptions of Mount Oyama progressively covered the volcano's slopes with more and more ash over the last half of 2000. This pair of images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) shows the volcano on July 17, 2000 (left) and September 3, 2000 (right). The false-color images combine infrared, red, and green light as red, blue, and green colors, respectively. Ash is dark gray, vegetation appears red, and water is blue-gray. In the image from September 3, steam is being vented from the volcano's caldera.
The volcano has again been venting steam, ash, and large amounts of sulfur dioxide (an estimated 20 to 50 kilotons per day) in February 2001. (See this previous SeaWiFS image of Miyakajima.) Scientists believe most of the emitted sulfur dioxide is from degassing magma within the volcano.
The 8-km-wide (5-mile) island is actually a low-angle stratovolcano rising some 818 meters (2,686 feet) up out of the Pacific Ocean, about 240 km (150 miles) south of Okinawa and 320 km (200 miles) east of Taiwan. Many now refer to the island as Miyakejima, and the volcano's summit as Mount Oyama.
Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team