Part of the “Ring of Fire,” a zone of frequent earthquakes and volcanic eruptions that partially rings the Pacific Ocean Basin, the island of Java in Indonesia is littered with active volcanoes. In May 2006, vulcanologists warily watched one of the island’s most active volcanoes: Merapi. Merapi had rumbled for weeks without a serious eruption, but in early May, its activity escalated. According to news reports, a plume of rock, ash, and hot gas flowed several kilometers down the volcano’s western slope. At its summit, the volcano built a lava dome, a kind of “cap” on pressurized volcanic material underneath.
The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard the Terra satellite took this picture on May 14, 2006. In this image, clouds have collected at Merapi’s summit, which is a fairly common occurrence. To the east of Merapi is Semeru Volcano, which also showed signs of unrest in May 2006, emitting plumes of volcanic ash.
According to the Sydney Morning Herald, while ordering residents of nearby villages to evacuate the area around Merapi Volcano, authorities warned of a more serious threat than lava flow. This volcano could also produce a gas cloud hot enough to instantly incinerate anyone or anything in its path, they said. The authorities warned that scorching gas, combined with rock fragments and ash, could stream down the side of the volcano at hundreds of kilometers an hour. Nevertheless, some locals refused to leave, some of them citing the need to care for their livestock. Authorities expected neither the nearby town of Magelang nor the provincial capital of Yogyakarta to face imminent danger, although, according to the CNN Website, the United Nations predicted that the volcano might displace as many as 80,000 people.
Both Merapi and Semeru rank among Indonesia’s most active volcanoes. Lying in a densely populated area, Merapi Volcano has periodically decimated cultivated crops on its western and southern flanks, and the upper portion of the volcano is bereft of vegetation due to frequent eruptions. To the east of Merapi, Semeru Volcano is Java’s highest volcano, rising 3,676 meters (over 12,000 feet) above the nearby coastal plains. Both volcanoes have claimed human lives with historical eruptions.
NASA image created by Jesse Allen, Earth Observatory, using data obtained from the Goddard Earth Sciences DAAC.