What did South Korea say caused the explosions heard near Ganghwa Island?

South Korea’s Joint Chiefs of Staff said the continuous explosion sounds appeared linked to North Korea’s reinforcement of coastal security facilities on the northern side of the Han River estuary.

Where were the explosions heard and what North Korean activities were reported nearby?

The sounds were heard from North Korean coastal areas north of the Han River estuary near the Ganghwa front. NHK reported that North Korea was conducting demolition and border fortification work in a border area near Ganghwa Island.

Why is Ganghwa Island considered a sensitive border area?

Ganghwa Island is just northwest of Incheon along the Han River estuary and lies close to the Military Demarcation Line. It is also an area where North Korean mines are often washed ashore into South Korea after heavy rains.

Explosions heard across border island likely tied to N. Korea's coastal reinforcement: S. Korean military

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Summary

Explosion sounds were continuously heard Tuesday from North Korean coastal areas north of the Han River estuary near Ganghwa Island. A South Korean Joint Chiefs of Staff spokesperson said the sounds appeared linked to North Korea reinforcing coastal security facilities. South Korea is closely monitoring related movements.

Key Facts

Capt. Jang Do-young, spokesperson for South Korea’s Joint Chiefs of Staff, described the sounds as continuous explosions from the North Korean coastal area north of the Han River estuary’s neutral waters.
North Korea was reportedly conducting demolition and border fortification work near Ganghwa Island, according to Japanese broadcaster NHK.
Ganghwa Island lies just northwest of Incheon along the Han River estuary and is among the South Korean islands closest to the Military Demarcation Line.
Heavy rains often wash North Korean mines ashore onto Ganghwa Island and other areas of South Korean territory.

By Yonhap

Published Oct 13, 2026 2:25 pm KST

A view of a North Korean county seen from Ganghwa Island off South Korea's west coast near the inter-Korean border, July 27, 2020 / Yonhap

Recent explosion sounds heard from the northern side of a western border island appear to be linked to North Korea's ongoing work to reinforce its coastal security facilities, a South Korean military official said Tuesday.

North Korea was seen conducting demolition and border fortification work in a border area near Ganghwa Island off South Korea's west coast, Japanese broadcaster NHK reported the previous day.

The media outlet quoted a Ganghwa resident who described hearing massive "booms" nearby, saying that nothing like this had ever happened in all his years living there.

"Explosion sounds are being continuously heard in the North Korean coastal area north of the neutral waters of the Han River estuary on the Ganghwa front," Capt. Jang Do-young, spokesperson of the South's Joint Chiefs of Staff (JCS), said during a press briefing.

"We judge that the North Korean military is reinforcing its coastal security facilities on the North's side and we are closely monitoring related movements," he added.

Located just northwest of Incheon along the Han River estuary, Ganghwa Island is one of the closest islands to the Military Demarcation Line (MDL) separating the two Koreas.

It is also known as one of the areas where North Korean mines are often washed ashore across the border into South Korean territory following heavy rains.

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