BEIJING — News of North Korea's most recent atomic test, which Pyongyang is claiming was its first detonation of a hydrogen bomb, has sparked new fears about the future. But there is a more immediate concern: Neighboring South Korea and China are increasingly worried that the underground nuclear tests could set off the dormant volcano Changbai Mountain (also known as Paektu).

According to Caixin media, China's National Earthquake Center monitored a seismic shock of magnitude 4.9 at 9.30 A.M. on Wednesday, some 80 kilometers southwest of Chongjin city, the known location of North Korea's nuclear test site. The epicenter of the earthquake was confirmed by monitoring centers in several other countries, and North Korea's official television station announced some two hours later, at noon, that the country had just "safely and perfectly" undertaken a successful first hydrogen bomb test. Several sources have shed doubt on whether the explosion was actually an H-bomb.

But Sina News reports that the severity of the earthquake following each North Korean nuclear test is escalating. South Korean experts say the test's impact range can stretch as far as 300 kilometers, and the test site is only 110 kilometers away from Changbai Mountain, which is called Baegdu-san in Korean.

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Lake atop Changbai Mountain — Photo: Bdpmax/GFDL

Some two-thirds of the dormant volcano lies in North Korean territory, with the rest on the Chinese side. It has erupted ten times over the past 1,000 years, with the last eruption occurring in 1903. South Korean experts believe that if the seismic shock created by a bomb test goes over magnitude 6.0, it could cause the volcano to explode.

Research quoted by Sina News suggests that, once the Changbai Mountain erupts, 60% of its destructive energy will rain down on Chinese territory. In 2014, President Xi Jinping signed an agreement with South Korea to carry out research on this very issue during his visit to the country.