Japan’s scarred and mountainous landscape betrays its highly active volcanic nature.
It sits on the so-called Ring of Fire, and more than 100 of the world’s 1,350 volcanoes are scattered across the country, many of which are active and ready to blow.
Iwo Jima is one of them, a dome created thousands of years ago which has reared its head in recent years.
Perhaps the most notable eruption came last year when so much volcanic ash and rock built up on the shallow seabed that an entirely new island was created.
Now, some scientists are warning that Iwo Jima risks erupting at an even greater rate this year.
Educational channel GeologyHub collated a list of the volcanoes most likely to erupt in 2024 at the beginning of the year, including along the southwest peninsula which went on to happen.
The entire central island of Iwo Jima consists of a massive resurgent dome of a 10km wide caldera. Because its magma chamber constantly refills, the island itself has been lifted around 62 feet since the end of World War 2.
This has occurred at a fairly consistent rate of 20 to 30 centimetres a year, but the last several years have seen a staggering 50 to 150 centimetres of annual uplift.
The movement has set into motion several volcanic eruptions, with Iwo Jima erupting in 2020, 2021, 2022, and 2023, including some underwater events.
In October 2023, perhaps the strongest volcanic eruption occurred along the seabed near Iwo Jima at an unnamed undersea volcano.
It produced such vast amounts of volcanic ash and rock that an entirely new island was created on the water’s surface.
By early November, the island measured around 100 metres in diameter and had reached a height of 20 metres above sea level, according to the Japan Meteorological Agency’s volcanic division. “This very vent may erupt again in 2024,” GeologyHub noted.
An eruption could, however, occur elsewhere on the island, and though it is a highly active region little in the way of constant and active monitoring is thought to be taking place.
This led Professor Albert Zijlstra from the University of Manchester to analyse some of the world’s volcanoes and develop a list of the ten most dangerous such vents in the world.
Writing on the Volcano Café blog in 2015, he identified Iwo Jima as the number one most dangerous volcano.
The whole point of the list was to show understudied and under-monitored volcanoes whose potential eruption would severely affect the surrounding areas, especially those near densely populated settlements.
While few people live on Iwo Jima itself, a large eruption would spark a tsunami that “could devastate southern Japan and coastal China including Shanghai and Hong Kong”.
Volcanologists at the University of Manchester estimate that the tsunami in Japan could be as much as 25 metres high.
An eruption of the similar-sized Kuwae volcano in 1458 caused a tsunami of 30 metres high in northern New Zealand and led to the cultural collapse of Polynesia.
