Mount Vesuvius: History, Eruptions, and Facts

A Volcanic Powerhouse

For Mount Vesuvius in Italy, the question isn't whether it will erupt, but when. Geologists and volcanologists who study the volcano agree that Vesuvius is overdue for an eruption [source: Fraser]. As a result, the Vesuvius Observatory continuously monitors seismic activity, gas levels, and other indicators to detect the earliest signs of an impending eruption.

The notorious volcano is most famous for its swift destruction of the nearby towns of Pompeii and Herculaneum in A.D. 79. Known as one of the deadliest volcanoes in the world, it is the only active volcano on mainland Europe. Despite this, approximately 700,000 people reside in the 18 towns located in the "red zone" at its base.

The red zone refers to the populated region that would be the first to face the brunt of an eruption. Within this 9-mile (12-kilometer) radius, people are in immediate danger, with little chance of survival if Vesuvius erupts again.

Vesuvius typically erupts andesite, a volcanic rock composed of 53-63% silica. This type of lava produces explosive eruptions, making Vesuvius highly unpredictable and a significant hazard.

Due to the imminent and unpredictable risk, the Italian government has put an evacuation plan in place to clear the red zone 72 hours before a potential eruption. Since 2004, the government has also offered $46,000 (30,000E) to encourage people to relocate out of the zone, though only a few have accepted the offer. Experts also caution that emergency measures should extend to nearby Naples, as an eruption could send hazardous ash and pumice up to 12 miles (20 kilometers) away [source: Fraser].

Mount Vesuvius is classified as a somma-stratovolcano. Stratovolcanoes have steeper slopes and a more conical shape compared to shield volcanoes, formed from thick, sticky lava produced by pyroclastic flows that doesn't spread easily. As a result, lava accumulates around the vent, creating a mountain-like volcano. A somma volcano, also known as a sommian, is a volcanic caldera partially covered by a new central cone.

Where can Mount Vesuvius be found?

Mount Vesuvius is located in the Campania region in Italy, a country in Europe. The volcano stands just to the east of the Bay of Naples, about 9 km (5.6 miles) from the bustling city of Naples. Vesuvius is part of the Campanian volcanic arc, a chain of volcanoes formed by the subduction zone where the African and Eurasian tectonic plates converge.

The History of Mount Vesuvius: Pompeii and Herculaneum

At 1 p.m. on August 24, A.D. 79, the eruption began. Nineteen hours later, the two affluent Roman cities, Pompeii and Herculaneum, were nearly obliterated from history. Early signs of the eruption included a mild earthquake and the draining of underground water sources a few days before the eruption [source: Stewart]. A towering plume of smoke shot up 20 miles (32 kilometers) into the sky, spewing scorching volcanic material.

The sole eyewitness to document the eruption, Pliny the Younger, likened the eruption’s plume to the shape of an umbrella pine tree, a defining characteristic of a plinian eruption. Soon, the city was suffocated by smoke and toxic volcanic gases. While many fled Pompeii, at least 2,000 who remained were either crushed or buried alive under the ash, rocks, and volcanic mud that rained down from the mountain that day.

Among the victims was Pliny the Younger’s uncle, the renowned Roman figure, Pliny the Elder. He was a Roman writer, philosopher, naturalist, and military and naval leader during the early Roman Empire.

On the other side of the mountain, near the Bay of Naples, the seismic storm moved toward Herculaneum. Along with the showers of ash and rocks, a sweltering heatwave of almost 900°F (482°C) swept over the region [source: Lorenzi]. Though many managed to flee the devastation caused by the volcano, 80 bodies were found, seemingly preserved in time, having perished instantly from the extreme thermal shock.

The eruption of A.D. 79 engulfed Herculaneum under 75 feet (22 meters) of ash, while Pompeii was buried under about 9 feet (2.7 meters). Due to the area being uninhabitable for centuries after the eruption, both cities faded from memory until their rediscovery in 1748. The fine dust and rapid rate at which it fell helped preserve much of Pompeii's structures, artifacts, and the countless bodies, all of which remained almost untouched until excavation began.

What archaeologists did not realize until more recently was that the infamous eruption wasn't the first nor the largest from Mount Vesuvius. Around 3,780 years ago, the volcano erupted with far more force, turning vast areas into desert for over 200 years [source: Than]. This eruption, known as the Avellino eruption, took the surrounding population by surprise, and archaeologists uncovered deeply embedded footprints in the area as a result.

The 1631 eruption claimed the lives of 4,000 people and obliterated six villages [source: Woods]. In more recent history, only a minor eruption occurred in 1944, resulting in 26 fatalities. While modern-day geologists can forecast the eruption's intensity, they are unable to pinpoint when it will happen, making Mount Vesuvius a ticking time bomb.

Notable Eruptions Pompeii to Present Day

In the following list, 'VEI' refers to the Volcanic Explosivity Index, which measures the strength of volcanic eruptions. Introduced in 1982 by Christopher G. Newhall of the United States Geological Survey and Stephen Self, the index determines an eruption's explosivity, ranging from 0 for the least explosive to 8, the highest level ever observed.

A timeline of confirmed volcanic eruptions and their associated impact scale.

The most recent eruption occurred in 1944, during World War II. It caused minimal damage and resulted in 26 fatalities. Lava flows were seen spilling over the crater of Mount Vesuvius. What began as minor eruptions escalated over the course of a week and a half, culminating in a powerful explosion. Fortunately, there was enough time for most people to evacuate.

New research suggests that future eruptions of Mount Vesuvius may be far more destructive. The volcano rests atop a vast magma chamber that spans 154 square miles (400 square kilometers) deep beneath the Earth. In comparison, Kilauea is the world’s most active volcano, with 34 eruptions since 1952, but its magma supply is much smaller than that of Vesuvius, which has erupted about 30 times since 79 A.D. Scientists predict that the next eruption will be an incredibly violent plinian explosion, characterized by flying rocks and ash traveling at speeds of nearly 100 miles per hour (160 kph).

The period of calm since 1944 is significantly longer than any in recent history, pointing to a possible change in Vesuvius’s eruption patterns. Some hypotheses suggest that the eruption of 1944 marked the end of an era of heightened volcanic activity. If these theories hold, the next major eruption could happen in a few decades or perhaps as far as several centuries from now. Historically, large eruptions from Mt. Vesuvius, which discharge around 1 cubic kilometer (0.24 cu mi) of volcanic material—such as the catastrophic eruption that buried Pompeii and Herculaneum—usually follow thousands of years of dormancy.

Mt. Vesuvius Today

A popular Italian National Park and Tourist Destination.

On June 5, 1995, the area surrounding Vesuvius was officially designated as a national park. Visitors are welcome to reach the summit of Vesuvius, and park authorities have established a network of trails around the volcano for those wishing to explore its surroundings.

Mount Vesuvius, with its towering stature and rich historical significance, draws tourists from around the world. This legendary volcano, responsible for the catastrophic eruption that buried the ancient cities of Pompeii and Herculaneum, now stands as a powerful symbol of nature's force and the enduring strength of human civilization.

The archaeological remnants of Pompeii and Herculaneum, preserved beneath thick layers of ash and pumice, offer a rare glimpse into the everyday life of ancient Romans. Strolling through these ancient cities feels like a journey back in time, with well-preserved streets, homes, and even artworks. These sites offer a direct link to history, making them a must-see for history buffs, archaeologists, and curious visitors alike.

In addition to its historical significance, the natural beauty surrounding Mount Vesuvius is a major attraction in itself. The mountain offers sweeping views of the Bay of Naples, and its diverse plant and animal life make it a prime destination for nature enthusiasts. The Vesuvius National Park, created to preserve the region's biodiversity, features a variety of hiking trails suitable for both casual walkers and experienced trekkers.

The blend of dramatic history, archaeological treasures, and natural beauty makes Mount Vesuvius a top-tier destination. In 2017, the Vesuvian archaeological sites welcomed a total of 4,023,900 visitors. Each year, millions of tourists, drawn by the stories of ancient eruptions and the allure of stunning views, continue to flock to the region, cementing its status as one of Italy's premier tourist attractions.

What would the outcome be if Mount Vesuvius erupted today?

If Mount Vesuvius were to erupt today, the consequences would be catastrophic. With its destructive potential, the eruption could put over 3 million people at risk and potentially destroy the city of Naples [source: Than].

Italy faces a complex crisis surrounding Mount Vesuvius. On one hand, Vesuvius is an active volcano capable of erupting at any time, with the power to devastate entire cities, much like it did to Pompeii and Herculaneum in A.D. 79. On the other hand, the volcano has become the epicenter of a national issue, with over 700,000 people living illegally on its slopes.

Across Italy, an estimated 6 million people live in illegally constructed homes, a result of years of governmental failure, from sheer incompetence to outright corruption. The rapid urban expansion of Italy in the mid-20th century led developers to quickly build homes that met public demand but often disregarded building codes. The government's typical approach has been to implicitly allow, and sometimes directly support, the circumvention of its own regulations.

This unchecked urban growth has made Vesuvius one of the world's most dangerous volcanoes. Lucia Pappalardo, a volcanologist, senior researcher at the Vesuvius Observatory, and native of Naples, stresses that a catastrophic eruption cannot be predicted, and the only way to safeguard the population is through proactive evacuation—a complicated task due to the region's high population density and lack of sufficient escape routes.

For years, the Italian government has largely ignored these glaring risks. It wasn’t until the 1980s that the government began imposing restrictions on urban growth near Vesuvius, establishing certain areas as 'red zones.' However, these measures were riddled with loopholes, enabling continued construction in these areas in exchange for amnesty payments, leaving people vulnerable and living dangerously close to the volcano until the next eruption strikes.

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