Explosive and effusive eruptions

THERE ARE TWO PREDOMINANT TYPES OF VOLCANIC ERUPTIONS: Effusive eruptions when magma rises through the surface and flows out of the volcano as a viscous liquid called lava. Explosive eruptions when magma is torn apart as it rises and reaches the surface in pieces known as pyroclasts.

The explosive eruptions Explosive eruptions are violent emissions of fragmented magma caused by the actions of gases contained in it and also by the effect of the vaporization of the water (that has external origin), which comes into contact with the magma.

The effusive eruption An eruption dominated by the outpouring of the lava onto the ground is often defined as an effusive eruption.

Lava flows generated by effusive eruptions change its shape, thickness, length and width depending on the type of lava erupted. a

The Precautions The fall of volcanic ash represents a health risk. Prolonged exposure can be dangerous and, for this reason, we should take some precautions to reduce problems.

1. Outdoors, wear a mask and glasses to protect against dust 2. In case of eye contact avoid rub; wash them with water 3. Stay indoors with the closed windows 4. Pets should be kept at home 5. Drive with particular caution 6. Don’t eat fruit and vegetables covered with ash without accurate washing

People exposed to falling ash or living in the dusty environment after an ash fall can suffer different problems. Respiratory problems such as nose and throat irritation, coughing, bronchitis-like illness and discomfort while breathing. The emission of Radon is also important. It is considered as a significant air contaminant. According to a report made by the EPA (Environmental Protection Agency) radon causes lung cancer.

Dry volcanic ash can stick to a moist human eye and the tiny ash particles quickly cause eye irritation. This problem is most severe among people who wear contact lenses; but there are also some skin irritations reported by people in ashfall areas.

Depending on where the volcano is located, the effects will be felt globally or at least by a whole hemisphere.

The explosive eruptions’ damages Large areas can be devastated by • pyroclastic flow deposits • volcanic gases, above all sulphur gases being particularly important. This gas is converted into sulphuric acid aerosols in the stratosphere and layers of aerosol can cover the global atmosphere within a few weeks to months or also it can cover the atmosphere for several years. One of the most important effects is the temporary reductions in light levels.

The effusive eruptions’ damages Effusive eruptions rarely kill anyone because they move slowly. People can usually be evacuated during an effusive eruption. Usually, the most dangerous problem is the destruction of roads and buildings.

The mount Aetna Mount Aetna is one of the most active volcanoes in the world. -Volcanic activity first took place at Aetna about 500,000 years ago, with eruptions occurring beneath the sea off the ancient coastline of Sicily. -From about 35,000 to 15,000 years ago, Aetna experienced some highly explosive eruptions, generating large pyroclastic flows, which left extensive ignimbrite deposits. -Aetna's most destructive eruption started on 11 March 1669. -F

-The first eruptions are to be found in the basalt columns of Acitrezza and Sant’Anastasia and pillows in Acicastello. A second series of eruptions, this time type alkali-basalt, is held between 200 and 100 thousand years ago, giving shape to the so-called Monte Calanna, the main prehistoric volcanic cones.

-The eruption of Etna in 1669, which is considered the most devastating period of history, it destroyed and buried dozens of villages coming down to the sea at the western districts of Catania.

unt Vesuvius is a stratovolcano in the Gulf of Naples, Italy, The mount vesuvius Mount Vesuvius is a stratovolcano in the Gulf of Naples, Italy, about 9 km east of Naples and a short distance from the shore. -Vesuvius is a distinctive "humpbacked" mountain, consisting of a large cone(Gran Cono) partially encircled by the steep rim of a summit caldera. -Vesuvius was formed as a result of the collision of two tectonic plates, the African and the Eurasian. unt Vesuvius is a stratovolcano in the Gulf of Naples, Italy, about 9 km east of Naples and a short distance from the shore. -Vesuvius is a distinctive "humpbacked" mountain, consisting of a large cone(Gran Cono) partially encircled by the steep rim of a summit caldera. -Vesuvius was formed as a result of the collision of two tectonic plates, the African and the Eurasian. Mount Vesuvius is a stratovolcano in the Gulf of Naples, Italy, about 9 km east of Naples and a short distance from the shore. -Vesuvius is a distinctive "humpbacked" mountain, consisting of a large cone(Gran Cono) partially encircled by the steep rim of a summit caldera. Vesuvio -Vesuvius was formed as a result of the collision of two tectonic plates, the African and the Eurasian.

The eruption of Vesuvius in 79 A.D. is the major -In 1631, different earthquakes occurred. They caused numerous bulges of the ground, which consequently provoked many eruptions, such as its last one in 1944, demonstrating the real activity of Vesuvius and denying his quiescence. The eruption of Vesuvius in 79 A.D. is the major eruption of Mount Vesuvius occurred in historical times. The eruption, which has radically altered the morphology of the volcano, caused the destruction of the cities of Herculaneum, Pompeii and Stabiae

Marta Barbagallo Federica Crisafulli Giulia Gallo Laura Patanè