7,300 years later: One of Earth’s most explosive volcanoes is quietly reloading - here's where it is and why it matters

Scientists say one of Earth’s most explosive volcanoes is slowly filling again with magma after thousands of years. The volcano is the underwater Kikai volcano located off the coast of Japan. It last erupted about 7,300 years ago in one of the biggest explosions in modern geological history. That eruption blasted out so much material it formed a large shallow crater called a caldera.

Researchers now say a part under this caldera has been slowly refilling with fresh magma for around 3,900 years, as per the report by Daily Mail. This slow refill is raising concern that another giant eruption could happen in the future. People have noticed steam coming from the crater and more than a dozen small earthquakes in recent years.

Magma slowly refilling

Seama Nobukazu from Kobe University said the new magma appears to be in the same reservoir as the old eruption. He added scientists need to understand how huge amounts of magma build up before big eruptions. During the ancient eruption, about 36 cubic miles of rock spread across roughly 1,700 square miles. Hot pyroclastic flows travelled up to 93 miles from the volcano.


That explosion is believed to have wiped out the prehistoric Jomon civilisation in southern Japan. The volcano is still active today, with a lava dome forming in the center for nearly 4,000 years, as stated by Daily Mail. Scientists used airgun arrays to send seismic waves into the Earth and study the underground structure. The data confirmed the size and shape of a hidden magma reservoir that is filling up.

New magma findings

Chemical tests showed the new magma is different from the material released in the last eruption.This suggests the magma under the lava dome is newly injected material. Similar giant calderas include Yellowstone in North America and Toba. These volcanoes often stay quiet for long periods before erupting again. Scientists say they still do not fully understand this “sleep and wake” cycle.

The study was published in Communications Earth & Environment. The current magma reservoir is estimated to lie about 1.5 to 3 miles below the surface, as cited by Daily Mail. This depth is similar to where magma sat before the last giant eruption. Researchers say this magma refill could be an early step toward another major eruption. Another earlier study warned a future eruption could throw debris into the atmosphere and block sunlight. This could create a “volcanic winter” and cooler temperatures.

Tsunami and earthquake risk

It might also trigger tsunamis affecting southern Japan, Taiwan, China, and even the Americas. Yoshiyuki Tatsumi said the chance of such an eruption in 100 years is about 1 percent. He warned deaths could reach about 100 million in the worst-case scenario. The volcano lies within the Ring of Fire, a major earthquake and volcano zone.

About 90 percent of the world’s earthquakes happen in this region. The Ring of Fire contains more than 450 volcanoes around the Pacific Ocean, as noted byDaily Mail. The area is dangerous because tectonic plates slide under each other, causing earthquakes and tsunamis. Scientists are watching closely because the volcano is slowly recharging, and understanding it may help predict future super eruptions.

FAQs

Q1. Where is the Kikai volcano located?

It is an underwater volcano off the coast of Japan that last erupted about 7,300 years ago.

Q2. Why are scientists worried about the volcano now?

Researchers say magma is slowly refilling beneath it, which could lead to a future large eruption.