Volcanoes can be eerie and mysterious, which is why people are so in awe of them. We never really know what might be brewing below the surface, and despite their apparent inactivity, some dormant volcanoes could awaken with little warning, potentially causing catastrophic damage.
1. Mount Fuji, Japan
Beneath its serene, snow-capped peak lies a potentially explosive threat. Though dormant since its last eruption in 1707, scientists warn that Mount Fuji remains an active volcano, with pressure steadily building beneath the surface. Japan’s Meteorological Agency continuously monitors seismic activity in the region, as even minor tremors could signal the beginning of a new eruption.
2. Mount Shasta, California
In Northern California, beneath its majestic slopes lies a potentially dangerous force. According to the Smithsonian Institution, Mount Shasta’s last significant eruption occurred in 1250. Scientists still classify it as a dormant but active volcano, meaning it could awaken with little warning. The region experiences frequent seismic activity; studies suggest that magma is still beneath the surface.
3. Mount Kilimanjaro, Tanzania
Composed of three volcanic cones—Kibo, Mawenzi, and Shira—only Kibo remains dormant, with signs of past activity like fumaroles near its crater. Though Kilimanjaro has not erupted in thousands of years, seismic studies suggest that magma still lingers beneath the surface.
4. Mount Vesuvius, Italy
Naples, Italy, has one of the most infamous volcanoes in history. It is best known for its catastrophic eruption in 79 AD, which buried Pompeii and Herculaneum. Despite its current dormancy, Vesuvius remains one of the most closely monitored volcanoes in the world due to its potential for sudden and explosive activity. The volcano last erupted in 1944; scientists believe pressure is steadily building beneath its surface. With over three million people living in its shadow, an eruption could have devastating consequences.
5. Mount Hood, Oregon
With its last significant eruption in the 19th century, geological studies reveal ongoing seismic activity and heat flow beneath the surface, indicating Mount Hood is far from dormant. The U.S. Geological Survey closely monitors the volcano for signs of unrest, as an eruption could trigger deadly lahars, landslides, and ashfall that would impact nearby communities and vital water supplies. With the city of Portland located just 50 miles away, the potential risks of an eruption make Mount Hood one of the most closely watched volcanoes in the Pacific Northwest.
6. Kilauea, Hawaii
Kīlauea, located on Hawaii’s Big Island, is one of the most active volcanoes in the world. Still, it also experiences periods of dormancy that can lull observers into a false sense of security. Despite its relatively quiet periods, Kīlauea remains a ticking time bomb, with magma constantly shifting beneath its surface. Its most recent significant eruption in 2018 reshaped the island’s landscape, destroying homes and infrastructure with relentless lava flows. Scientists closely monitor Kīlauea for seismic activity and ground deformation.
7. Mount St. Helens, Washington State
This dormant volcano is infamous for its catastrophic 1980 eruption that reshaped the landscape and served as a stark reminder of the power of nature. Although it has remained relatively quiet in recent years, Mount St. Helens is still considered an active volcano with the potential to erupt anytime. Since its last major eruption, scientists have observed periodic seismic activity, dome-building eruptions, and gas emissions, indicating that magma continues to accumulate beneath the surface.
8. Mount Merapi, Indonesia
Mount Merapi, located on the densely populated island of Java, Indonesia, is one of the world’s most active and dangerous volcanoes. Though it experiences frequent minor eruptions, its potential for a significant explosive event keeps scientists and residents on high alert. Known for its deadly pyroclastic flows—fast-moving clouds of hot gas and volcanic material—Mount Merapi’s eruptions have historically claimed thousands of lives and devastated nearby villages. Despite its dormancy, ongoing seismic activity and gas emissions suggest that pressure is steadily building beneath the surface.
9. Mount Ruapehu, New Zealand
As an active stratovolcano, Ruapehu has a history of periodic eruptions, with the most recent significant activity occurring in the early 2000s. The volcano is home to Crater Lake, a boiling, acidic body of water that is a key indicator of volcanic activity. Scientists closely monitor changes in temperature, gas emissions, and seismic activity, as sudden eruptions could trigger deadly lahars—mudflows that can race down the mountain’s slopes, endangering local communities and infrastructure.
10. Tungurahua, Ecuador
While it has been erupting intermittently since the late 1990s, the volcano is still dormant in its more peaceful periods, and experts are vigilant about its potential for sudden, violent eruptions. Tungurahua’s eruptions often produce ash plumes, pyroclastic flows, and lava domes, posing serious risks to nearby towns and the thousands of people living in its shadow. Tungurahua remains a volatile and closely monitored volcano, with scientists watching for signs of increased activity that could lead to another explosive event, the last being in 2016.
11. Taal Volcano, Philippines
Situated on the island of Luzon, Taal has erupted more than 30 times in recorded history, with its most recent eruption in January 2020 sending ash plumes up to 15 kilometers high and displacing hundreds of thousands of people. Despite its frequent activity, Taal is often considered a “dormant” volcano between eruptions, as it can remain quiet for long periods. However, beneath its seemingly calm surface, the threat of sudden eruptions remains ever-present, as evidenced by its explosive past. The volcano sits within a lake, adding to the complexity of potential hazards, including deadly volcanic tsunamis.
12. Erta Ale, Ethiopia
Known for its persistent lava lake, Erta Ale is an active shield volcano that has been erupting for decades, though it has experienced periods of relative dormancy. Its continuous lava lake is one of the few in the world, and while it often shows signs of quiet activity, seismic events and sudden changes in lava behaviour can signal a significant eruption. The volcano’s remote location in one of the planet’s hottest and most inhospitable regions makes it difficult to monitor closely. However, scientists are still wary of its potential to unleash devastating lava flows and ash clouds.
