TEMPO.CO, Jakarta - A TikTok post [archive] claims that underwater volcanoes in the United States (US) and Japan will erupt simultaneously, triggering a major disaster.
The content, which circulated on June 27, 2026, stated that the underwater volcano in the US is 600 kilometers wide, while in Japan it is 557 kilometers wide. "Japan will soon be destroyed, there is a 557-kilometer-wide volcano under the Japanese sea ready to erupt," the post read.
As of June 30, 2026, the content had been reshared 690 times and liked by 3,552 TikTok users. However, is it true that underwater volcanoes in the US and Japan will erupt simultaneously?
FACT CHECK
Tempo's Fact Check team verified the claim by interviewing volcanologists, tracking the source of the photo, and examining official reports from volcanology authorities in Japan and the United States. They found no scientific evidence or official warnings that underwater volcanoes in the two countries would erupt simultaneously.
Distant Volcanoes Erupting Simultaneously Is Unlikely
Sukir Maryanto, a volcanologist from Brawijaya University, explained that simultaneous volcanic eruptions—especially between underwater volcanoes that are far apart—are extremely unlikely.
"Even neighboring volcanoes are unlikely to influence each other, let alone those that are far apart. Unless the volcanoes are connected in the same volcanic system," Sukir said when contacted by Tempo on Tuesday, June 30, 2026.
The official website of the United States Geological Survey (USGS), the official portal of the United States government's scientific and mapping agency, also states that there is no definitive evidence that an eruption at one volcano can trigger volcanic activity at another volcano hundreds of kilometers away or on a different continent.
Throughout history, simultaneous eruptions have only occurred at volcanoes or volcanic vents within a 10-kilometer radius, and even then, it is difficult to determine whether one eruption actually triggered another.
Most volcanic activity and earthquakes occur along tectonic plate boundaries, such as the Pacific Ring of Fire. Japan is located in this 40,000-kilometer-long active zone, adjacent to an arc of islands stretching from Tonga, Indonesia, and the Philippines to the west coast of North America and the Andes Mountains.
Currently, Japan has more than 50 active volcanoes that are closely monitored by the Japan Meteorological Agency (JMA). Although some volcanoes are at Level 2 and Level 3 alert levels, the JMA maintains that activity is normal and has not issued warnings of a major eruption that could devastate Japan. Life there continues to proceed as normal.
Using a Photo of the Anak Krakatau Eruption
The photo used in the post does not capture the eruption in the US or Japan, but rather the 2018 eruption of Anak Krakatau in the Sunda Strait, Indonesia.
According to a VOA report, the photo, taken by Reuters photographer Muhammad Adimaja, was taken on December 28, 2018, from the Indonesian Navy Patrol Vessel KRI Torani 860, as Mount Anak Krakatau was spewing hot ash.
Regarding the claim of a 557-kilometer-wide underwater volcano in Japan, Tempo found no scientific documents or official reports confirming this data.
On the other hand, the USGS, through its Volcano Hazards Program, continues to monitor 170 potentially active volcanoes in the US in real time. Currently, only Mount Great Sitkin is on Alert status, while Mount Kilauea, Shishaldin, and Kupreanof are on Warning status. The USGS has not issued any warnings regarding the potential for a simultaneous eruption with the Japanese volcano.
CONCLUSION
Tempo's verification concludes that the claim that underwater volcanoes in the US and Japan will erupt simultaneously in 2026, wiping out Japan is false.
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