September 29, 2014

Rescue teams searching Japan’s Mount Ontake volcano for missing hikers suspended operations this morning as the volcano continued to shoot gas, ash, and rocks high into the air. The 10,062-foot (3,066-meter) volcano, which is approximately 125 miles (200 kilometers) west of Tokyo, erupted unexpectedly on September 27. At least 36 people died in the eruption, and dozens of others were injured. Some 45 people remain missing. While most of the hundreds of hikers on the volcano on Saturday were able to walk down to safety, others were trapped in a suffocating cloud of volcanic gas and debris rolling down the flanks of the mountain.

Magma (molten rock) forms deep underground and rises toward the surface, left, collecting in a magma chamber. As pressure builds, the chamber breaks open and magma rises through a conduit, right. At openings called vents, the magma erupts as gas, lava, and pyroclasts (rock and ash). Layers of erupted lava and pyroclasts make up the body of a stratovolcano, shown here. (WORLD BOOK illustrations by Jay Bensen)

Television images show Mount Ontake’s upper slopes blanketed in ash, and rescuers report that bodies have been found buried in ash up to 20 inches (50 centimeters) deep. The Japan Meteorological Agency predicts further eruptions and warns that volcanic debris will likely continue to fall in a radius of 2.5 miles (4 kilometers) from the peak. The eruption was preceded by several minor earthquakes, which seismologists did not interpret as harbingers of a major event.

Additional World Book articles:

• Ring of Fire
• Geology 1991 (a Back in Time article)
• The Biggest Eruptions on Earth (a special report)