Eruption of Mount Vesuvius in AD 79
Encyclopedia
In the year of AD 79, Mount Vesuvius
erupted in one of the most catastrophic and famous eruptions
of all time. The Roman
vicinities of Pompeii
, Herculaneum
and Stabiae
were affected, and Pompeii and Herculaneum were obliterated. Mount Vesuvius spawned a deadly cloud of stone
s, ash
and fumes to a height of 20.5 miles, spewing
molten rock
and pulverized pumice
at the rate of 1.5 million
tons per second, ultimately releasing a hundred thousand times the thermal energy
released by the Hiroshima bombing
.
Since systematic excavations began in Pompeii in 1860, excavators have uncovered within the city limits the petrified-ash shells of the decomposed bodies of 40 victims. Historians
discovered that the vicinity was obliterated by pyroclastic flow
s. Pliny the Younger
, a Roman administrator and poet
, was the author of an account of the eruption, which was successful in rendering its nature.
authorized an account of the eruption —
An estimated 16,000 citizens in the Roman
vicinities of Pompeii
and Herculaneum
perished due to hydrothermal pyroclastic flow
s at temperature
s up to 700 °C (1292 °F). A precursor, the Avellino eruption
in the Bronze Age
, deposited about 0.32 km3 of white pumice
("the white pumice phase"), while a second, more intense explosion raised a column of 31 km (101,706 ft) depositing 1.25 km3 of grey pumice ("the grey pumice phase"); however, the 79 eruption produced a rain of pumice southward of the cone that built up to depths of 2.8 metres (9.2 ft) at Pompeii.
The eruption of Vesuvius in 79 unfolded in two phases, a Plinian eruption
that lasted eighteen to twenty hours, followed by a pyroclastic flow
or nuée ardente in the second, Peléan phase
that reached as far as Misenum but was concentrated to the west and northwest. Two pyroclastic flows engulfed Pompeii, burning and asphyxiating the stragglers who had remained behind. Oplontis
and Herculaneum
received the brunt of the flows and were buried in fine ash and pyroclastic deposits.
Stratigraphic studies of the eruption were compared to the eruption of the Bronze Age
and allegations of a possible future disaster were put forward. Since the eruption of 1944, Vesuvius has been relatively silent; however, it was theorized that the longer it remains silent, the worse the eruption, especially a danger to the densely populated area around the volcano.
Mount Vesuvius
Mount Vesuvius is a stratovolcano in the Gulf of Naples, Italy, about east of Naples and a short distance from the shore. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently erupting...
erupted in one of the most catastrophic and famous eruptions
Types of volcanic eruptions
During a volcanic eruption, lava, tephra , and various gases are expelled from a volcanic vent or fissure. Several types of volcanic eruptions have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed...
of all time. The Roman
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....
vicinities of Pompeii
Pompeii
The city of Pompeii is a partially buried Roman town-city near modern Naples in the Italian region of Campania, in the territory of the comune of Pompei. Along with Herculaneum, Pompeii was destroyed and completely buried during a long catastrophic eruption of the volcano Mount Vesuvius spanning...
, Herculaneum
Herculaneum
Herculaneum was an ancient Roman town destroyed by volcanic pyroclastic flows in AD 79, located in the territory of the current commune of Ercolano, in the Italian region of Campania in the shadow of Mt...
and Stabiae
Stabiae
Stabiae was an ancient Roman town, located close to the modern town of Castellammare di Stabia approximately 4.5 km southwest of Pompeii. It was positioned on a 50 m high headland overlooking the Gulf of Naples...
were affected, and Pompeii and Herculaneum were obliterated. Mount Vesuvius spawned a deadly cloud of stone
STONe
is a Japanese manga written and illustrated by Sin-Ichi Hiromoto. Kodansha released the two bound volumes of the manga on April 23, 2002 and August 23, 2002, respectively.The manga is licensed for an English-languague released in North America be Tokyopop...
s, ash
Volcanic ash
Volcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...
and fumes to a height of 20.5 miles, spewing
Volcanology
Volcanology is the study of volcanoes, lava, magma, and related geological, geophysical and geochemical phenomena. The term volcanology is derived from the Latin word vulcan. Vulcan was the ancient Roman god of fire....
molten rock
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
and pulverized pumice
Pumice
Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...
at the rate of 1.5 million
Million
One million or one thousand thousand, is the natural number following 999,999 and preceding 1,000,001. The word is derived from the early Italian millione , from mille, "thousand", plus the augmentative suffix -one.In scientific notation, it is written as or just 106...
tons per second, ultimately releasing a hundred thousand times the thermal energy
Thermal energy
Thermal energy is the part of the total internal energy of a thermodynamic system or sample of matter that results in the system's temperature....
released by the Hiroshima bombing
Atomic bombings of Hiroshima and Nagasaki
During the final stages of World War II in 1945, the United States conducted two atomic bombings against the cities of Hiroshima and Nagasaki in Japan, the first on August 6, 1945, and the second on August 9, 1945. These two events are the only use of nuclear weapons in war to date.For six months...
.
Since systematic excavations began in Pompeii in 1860, excavators have uncovered within the city limits the petrified-ash shells of the decomposed bodies of 40 victims. Historians
History
History is the discovery, collection, organization, and presentation of information about past events. History can also mean the period of time after writing was invented. Scholars who write about history are called historians...
discovered that the vicinity was obliterated by pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...
s. Pliny the Younger
Pliny the Younger
Gaius Plinius Caecilius Secundus, born Gaius Caecilius or Gaius Caecilius Cilo , better known as Pliny the Younger, was a lawyer, author, and magistrate of Ancient Rome. Pliny's uncle, Pliny the Elder, helped raise and educate him...
, a Roman administrator and poet
Poet
A poet is a person who writes poetry. A poet's work can be literal, meaning that his work is derived from a specific event, or metaphorical, meaning that his work can take on many meanings and forms. Poets have existed since antiquity, in nearly all languages, and have produced works that vary...
, was the author of an account of the eruption, which was successful in rendering its nature.
Characteristics
Pliny the YoungerPliny the Younger
Gaius Plinius Caecilius Secundus, born Gaius Caecilius or Gaius Caecilius Cilo , better known as Pliny the Younger, was a lawyer, author, and magistrate of Ancient Rome. Pliny's uncle, Pliny the Elder, helped raise and educate him...
authorized an account of the eruption —
Broad sheets of flame were lighting up many parts of VesuviusMount VesuviusMount Vesuvius is a stratovolcano in the Gulf of Naples, Italy, about east of Naples and a short distance from the shore. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently erupting...
; their light and brightness were the more vivid for the darkness of the nightNightNight or nighttime is the period of time when the sun is below the horizon. This occurs after dusk. The opposite of night is day...
... it was daylight now elsewhere in the world, but there the darkness was darker and thicker than any night.
An estimated 16,000 citizens in the Roman
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....
vicinities of Pompeii
Pompeii
The city of Pompeii is a partially buried Roman town-city near modern Naples in the Italian region of Campania, in the territory of the comune of Pompei. Along with Herculaneum, Pompeii was destroyed and completely buried during a long catastrophic eruption of the volcano Mount Vesuvius spanning...
and Herculaneum
Herculaneum
Herculaneum was an ancient Roman town destroyed by volcanic pyroclastic flows in AD 79, located in the territory of the current commune of Ercolano, in the Italian region of Campania in the shadow of Mt...
perished due to hydrothermal pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...
s at temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
s up to 700 °C (1292 °F). A precursor, the Avellino eruption
Avellino eruption
The Avellino eruption of Mount Vesuvius refers to a Plinian-type eruption that occurred in the 2nd millennium BC and is estimated to have had a VEI of 6...
in the Bronze Age
Bronze Age
The Bronze Age is a period characterized by the use of copper and its alloy bronze as the chief hard materials in the manufacture of some implements and weapons. Chronologically, it stands between the Stone Age and Iron Age...
, deposited about 0.32 km3 of white pumice
Pumice
Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...
("the white pumice phase"), while a second, more intense explosion raised a column of 31 km (101,706 ft) depositing 1.25 km3 of grey pumice ("the grey pumice phase"); however, the 79 eruption produced a rain of pumice southward of the cone that built up to depths of 2.8 metres (9.2 ft) at Pompeii.
Stratigraphic studies
Plinian eruption
Plinian eruptions, also known as 'Vesuvian eruptions', are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in AD 79 ....
that lasted eighteen to twenty hours, followed by a pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...
or nuée ardente in the second, Peléan phase
Pelean eruption
Peléan eruptions are a type of volcanic eruption. They can occur when viscous magma, typically of rhyolitic or andesitic type, is involved, and share some similarities with Vulcanian eruptions. The most important characteristics of a Peléan eruption is the presence of a glowing avalanche of hot...
that reached as far as Misenum but was concentrated to the west and northwest. Two pyroclastic flows engulfed Pompeii, burning and asphyxiating the stragglers who had remained behind. Oplontis
Oplontis
Oplontis was a town near Pompeii, in the Roman Empire. On August 24, AD 79, the eruption of Mount Vesuvius buried it under a deep layer of ash. It is today the location of the Villa Poppaea, the villa of the wife of Emperor Nero, which was excavated in the mid-20th century and is open to the...
and Herculaneum
Herculaneum
Herculaneum was an ancient Roman town destroyed by volcanic pyroclastic flows in AD 79, located in the territory of the current commune of Ercolano, in the Italian region of Campania in the shadow of Mt...
received the brunt of the flows and were buried in fine ash and pyroclastic deposits.
Stratigraphic studies of the eruption were compared to the eruption of the Bronze Age
Avellino eruption
The Avellino eruption of Mount Vesuvius refers to a Plinian-type eruption that occurred in the 2nd millennium BC and is estimated to have had a VEI of 6...
and allegations of a possible future disaster were put forward. Since the eruption of 1944, Vesuvius has been relatively silent; however, it was theorized that the longer it remains silent, the worse the eruption, especially a danger to the densely populated area around the volcano.