The serene waters of sky pond, one of the most popular tourist attractions in northeastern Asia, belie the fact that it is nestled inside the crater of one of the region’s most dangerous volcanoes—a peak known as Changbai Mountain to the Chinese and Mount Paektu to Koreans. That 2,744-meter-tall volcano, which straddles the border between China and North Korea, last erupted in 1903 but has displayed signs of awakening in recent years.

The lake is the source of three Asian rivers that, during an eruption, could serve as conduits for lahars—devastating blends of hot ash, mud and water that have the consistency of wet cement. A major eruption could send such flows racing down the volcano’s slopes, threatening hundreds of thousands of people.

The massive earthquake and tsunami that devastated Japan in March spurred regional scientists into action. This past August teams of geologists from China and North and South Korea, in an unusual collaboration, carried out field studies on the peak and planned to hold a workshop this fall on forecasting and preparing for a natural disaster. Tapping into a seismic network installed on the Chinese side of the mountain in 1999 as well as readings from GPS equipment on the volcano’s slopes, researchers have detected a series of shallow earthquakes as well as a gradual rise in the peak since 2002, which investigators believe is being caused by the movement of magma into a chamber below the volcano. The scientists think the magma is coming from deep inside the earth’s mantle, which may make an eruption more likely.

Despite the international collaboration, data sharing to date has been sparse, says Sung-hyo Yun of Pusan National University in South Korea. “So far the work has not been easy,” he notes.

This article was originally published as "Sleeping Giant".