When volcanoes erupt they do so in different ways. There are some factors that cause eruptions to have different characteristics and consequences. In this case, we are going to focus on the type of strombolian eruption. The La Palma volcano has a strombolian eruption. What do means this?
In this article we are going to tell you everything you need to know about the Strombolian eruption, its characteristics, origin and consequences.
Table of Contents
What is a strombolian eruption
A Strombolian eruption an explosive volcanic eruption that alternates between intense and calm activity. It is a typical eruption of volcanoes in the Canary Islands, such as the volcano on the island of La Palma, which takes its name from the Stromboli volcano on the small Aeolian islands near Sicily, Italy.
The explosions of Strombolian eruptions are produced by the accumulation of gases released by the magma itself as it ascends. Strombolian volcanoes spew gas, ash, lava, and volcanic bombs with such force that they shoot volcanic plumes several kilometers high.
The magma temperature in these eruptions is usually around a thousand degrees Celsius.
Types of explosive eruptions
Our starting point is that volcanoes are a complex natural process that begins deep inside the Earth, where magma forms in the mantle, continues to rise through the crust, and is expelled outward. Magma is a mixture of molten rock, gases, and liquids that arises within the Earth. When the magma reaches the surface, its name becomes lava. Not all magma is the same, and therefore, the lava from volcanoes is not the same.
Volcanic eruptions have varying degrees of eruption. In fact, volcanologists use a scale called the Volcanic Explosivity Index (VIE) to measure the strength of a volcano. There are octaves in this scale.
In all explosive eruptions, gases and pyroclastics are violently ejected into the atmosphere, but within this category, some are more violent than others. Strombolians are the least destructive of the explosive eruptions when we consider that they can produce catastrophic explosions, such as that of the Krakatoa volcano in 1883, which devastated the Indonesian archipelago of the same name.
Other explosive eruptions are:
- Vulcan: this material is more viscous than a Strombolian eruption, so more pressure builds up in the magma chamber as the magma rises.
- Peleana: composed of more viscous material than Strombolian eruptions, characterized by bright ash avalanches or pyroclastic flows and formation of lava domes and pumice cones.
- Plinian: They are highly explosive, with very violent manifestations, expulsion of large volumes of volcanic gases, debris and ash from magma with an acid composition. The volcanic gases it spews out are highly toxic and the lava is rich in silicates. It received its name in honor of Pliny the Elder, who died in AD 79. C. when Mount Vesuvius erupted and buried Pompeii. It was the first such eruption described and was carried out by Pliny the Elder's nephew Pliny the Younger.
Strombolian Rash Risks
There are different types of volcanic eruptions, depending on the explosiveness of the volcano and the lava flow.
The characteristic of the Strombolian volcano is that the eruption is sporadic, generally not very violent, and the lava does not erupt continuously. Volcanoes release pyroclastic material (a hot mixture of gas, ash, and rock fragments) from cracks in the Earth's surface. Its duration can vary from a few weeks to several months.
Strombolian volcanoes typically reach heights of up to 1.000 meters and spew more than 10.000 cubic meters of material. In addition to strombolians, experts distinguish five other types of eruptions. The least risky volcanic activity is the Hawaiian volcano, which has very little pyroclastic material, hardly any explosions, and the lava is quite fluid. The second is vulcanian, spewing large clouds of pyroclastic material and large amounts of volcanic ash.
The Plinian eruption, on the other hand, is one of the most spectacular (and terrifying), with very violent explosions, a lot of ash and abundant sticky lava. Magma can collapse mountain tops and create craters. On the other hand, those Peleano-type lavas solidified rapidly, forming a plug in the crater. Finally, hydrovolcanic eruptions occur due to the interaction of magma and water.
A single explosion typically ejects pyroclastic volumes ranging from 0,01 to 50 cubic meters. at variable discharge speeds ranging from 104 to 106 kg/s. When eruptive activity is prolonged, the thicker material in the proximal region often forms cinder cones that can reach heights of several hundred meters. Lava spatter, bomb deposits and blocks can often be seen in close proximity to pipes and ash deposits in intermediate distance areas.
Due to transient changes in eruption patterns and variability in volcanic ash dispersal, the proximal and distal members of Cascade deposits may also show a pronounced bedrock, with interbeds of volcanic ash and rock, while the nascent components show gas bubbles and changes in crystallinity.
Short-lived Strombolian eruptions fed by basaltic magma, such as the one observed at Llaima volcano in May 1994, spew fine volcanic ash to form pyroclastic formations consisting of black ash and angular morphologies, glass, plagioclase crystals, olivine, and oxides of iron and titanium.
As an example of a Stromboli eruption that continued to form cinder cones over time, an iconic and well-documented case in South America is the 1988-89 Christmas eruption. There are scientists who extensively studied the evolution of the eruptive cycle and the characteristics of the ejected material, the latter corresponding to: 1) volcanic ash composed mainly of irregular scoria with a low proportion of crystals; 2) subspherical to irregular 3) Bombas and even metric, expand close (<2km) to the duct, with fusiform, flattened subspherical, braided, and irregular and flattened morphologies; 4) There are very few accidental and accessory character blocks.
I hope that with this information you can learn more about the Strombolian eruption and its characteristics.