The different types of volcanoes are geological structures that amaze the population because they are usually impressive on the earth’s crust, in addition, in several countries they are a reason for tourist attraction and various sports such as hiking and climbing.
For this reason we consider it necessary to explain the different types of volcanoes, their formation and examples.
Types of volcanoes according to their activity
Active volcanoes
They are those volcanoes that have erupted in the last 10,000 years. However, at any time they can enter into eruptive activity with or without internal or external manifestations, such as seismic activity and expulsion of material.
Most of the time, the volcano remains at rest while it is active, that is, the processes of eruptive activity also include the rest times of the volcano and can last from one hour to years.
Despite the monitoring of these volcanoes, no reliable method has yet been found to predict volcanic eruptions.
Examples
- Cotopaxi volcano in Ecuador
- Eyjafjallajökull, is a stratovolcano, located in Iceland with an elevation of 1666 meters.
- Mount Vesuvius, is located in Italy 9 km east of Naples, has a height of 1281 meters above sea level.
- Sakurajima, is a stratovolcano that is located in Japan in the Kagoshima Bay and has an altitude of 1117 meters.
- Mount Merapi, stratovolcano located in Indonesia and has an elevation of 2910 meters.
Dormant volcanoes
These volcanoes have not had any eruptive event or frequent volcanic activity for a long time. However, some maintain certain signs of activity and it is observed by the presence of hot springs.
Fumaroles and volcanoes with long periods of inactivity between eruptions are also included in this type. It cannot be ruled out that these volcanoes did not erupt, as they can go from a state of inactivity to activity without prior notice.
examples
- Mount Fuji, is located on the island of Honshu, Japan with an elevation of 3776 meters.
- Xitle volcano, located in Mexico City, with an altitude of 3100 meters above sea level.
- Diamond Head or Diamond Head, located in Hawaii with an altitude of 232 meters.
Extinct volcanoes
They are those that have a low possibility of presenting volcanic activity. Its last eruption is considered to have been more than 25,000 years ago.
These do not have a supply of magma in their magma chamber because they were moved away from their source either by the movement of the tectonic plates, which gradually caused their inactivity. These cases occur in volcanoes of hot spots or hotspots.
However, the possibility that they did not erupt should not be ruled out, in case they do, it can cause catastrophic disasters, even more than that of an active volcano. They are uncertain volcanoes, it is difficult to determine their behavior, because there is no record of their signs.
examples
- Mojana Volcanic Complex – Fuya Fuya, 4279 masl, located north of Ecuador, between the provinces of Pichincha and Imbabura.
- Chalupas volcano, 4878 masl, located in the province of Napo, Ecuador.
- Pan de Azúcar volcano, 3482 masl, located 20 km ENE of Baeza, Ecuador.
Types of volcanoes by their shape
Shield volcano
They are volcanoes that have a height less than their diameter, their shape is the result of the low viscosity of the magma of basaltic composition and the successive accumulation of very fluid lavas. So they have a slight slope, considerable height and a rounded profile. There is little presence of pyroclasts.
The eruptions of this type of volcanoes have a low explosiveness, present Hawaiian-type effusive eruptions, do not constitute a danger to humans, good monitoring allows the population to be evacuated on time and correctly.
Examples:
- Mauna Kea volcano, has an altitude of 4207.3 meters above sea level, located on the Island of Hawaii.
- Kilauea volcano, has an altitude of 1247 meters above sea level and is located on the Island of Hawaii.
- Sierra Negra volcano, has 1124 meters above sea level, located south of Isabel Island, Galapagos archipelago, Ecuador.
- Fernandina Volcano, is 1476 meters above sea level, located in the Galapagos Islands, Ecuador.
Caldera type volcano
This volcano presents a sunken or depression shape, due to the internal collapse of the volcano.
There are two ways for its formation, the first is the result of a large violent eruption generated by the obstruction of the chimney that destroys the building, forming a caldera and the second occurs due to the decrease in pressure in the magma chamber when it is partially empty, which generates the collapse of the building.
Volcanic caldera
Craters are conduits that expel magma, they are shaped like depressions that do not exceed several hundred meters in depth and diameter, unlike calderas that have a much larger extension than craters, ranging from kilometers to 60 kilometers or more.
They are located at the top of the volcano, have steep walls and circular structures associated with the central areas of the volcanic edifice.
These are associated with large pyroclastic eruptions that erupt enormous amounts of magmas and because the volcano is not capable of draining such an amount, it causes a depression in the upper part of the volcano, forming the caldera.
These cases occur when the magma chamber is partially emptied, it is not so deep and it is a few kilometers below the surface of the earth, which causes the roof of the magma chamber to collapse.
Examples:
- Aniakchak volcano, approximately 10 km in diameter, is located in the Aleutian Range in Alaska, USA.
- Mount Mazama, is covered by Crater Lake, located in the state of Oregon, USA.
- Caldera of the La Cumbre volcano, has a height of 1476 meters, is located in the Fernandina Islands in the Galapagos Islands, Ecuador.
- Yellowstone, with an altitude of 3142 meters above sea level, the caldera measures approximately 55 x 72 km, is located northwest of Wyoming, in the United States.
Strato volcano or composite volcanoes
They are high-altitude volcanoes, conical in shape and with a central crater, the result of periods of explosive activity, forming by layers of materials one on top of the other throughout their evolution, successive layers of hardened lava, pyroclastic deposits and ash emitted by a main vent., gradually forming its cone in each eruption.
Composite cones are formed by relatively viscous flowing lavas of andesitic composition, they can eject viscous lavas for extended periods as well as shift and release pyroclastic materials.
They present an almost symmetrical, steep profile and periodic and explosive eruptive events. The lavas that flow from its interior are highly viscous and cool before they travel long distances.
In these eruptions, pyroclastic flows also known as burning cloud or incandescent avalanche occur, they are composed of hot gases and floating particles, they move down the slope at speeds of approximately 200 km/h.
The pyroclastic flows transport rock fragments and due to the rebound in the expanding hot gases, they can be deposited at more than 100 km. The magmatic source is acidic in composition with a high silica content, with the presence of andesite, rhyolite and dacite rocks.
These volcanoes generally originate in subduction zones, along tectonic plate boundaries either where oceanic crust subducts under continental crust or oceanic crust, forming chains or arcs. Examples of these are the Andes and Iceland.
Examples:
- Mount Vesuvius, has an altitude of 1281 meters, located nine kilometers from the city of Naples.
- Teide, with an altitude of 3718 meters, located on the island Tenerife, Spain.
- El Misti with a height of 5822 meters above sea level, is located near the city of Arequipa, in Peru.
- Ubinas with a height of 5670 meters above sea level, located in the district of Urbinas, in southern Peru.
Volcanic dome
They originate from the slow accumulation of highly viscous lava and therefore have strong circular mound-shaped slopes, they can reach heights of hundreds of meters and they form slowly, growing over months or years.
They are located on the emission ducts of volcanoes, the evolution and dimensions depend on the characteristics of the magma, it increases in size as the internal pressure of the gases increases, this can cause an explosive event of low or high intensity that forms breccias of explosion moving around the crater.
The collapse of the dome in some cases generates pyroclastic flows due to the content of molten rock and gases, which is one of the most latent forms of volcanic eruption.
They can form within a caldera or volcano and also form individually, as the main volcanic structure.
examples
- Las Derrumbadas, rhyolitic volcanic domes, comprised of the Red Collapsed dome with an altitude of 3,480 masl and the Blue Collapsed dome with an altitude of 3,420 masl, are located in the state of Puebla, Mexico.
- The Pululahua complex, is made up of several domes, is located near the middle of the world, in the Province of Pichincha Ecuador.
- Teodoro Wolf and Yerovi domes, located in the Cuicocha lagoon, Ecuador.
Cinder or slag cone
They are small volcanoes, in some cases they exceed more than 300 m in height and have a plate-shaped crater at the top, they are generally formed of pyroclasts, they have a semi-solid lava, composed of ash and viscous lava, the slopes usually have 30 to 40 degrees.
Their activity is not so recurrent, they usually have a single eruption that can last weeks or a few years and these originate from the eruption of a single conduit, the eruptions are explosive with a predominance of pyroclastic and the magma is generally basaltic rich in gas.
After the eruption has occurred, the magma that is in the tube that connects the chimney and the magma chamber solidifies and therefore the volcano becomes inactive.
For cone growth, a surrounding ring of pyroclastic materials composed of lapilli, ash, and coarse materials forms around the crater. If it is composed of fine material, it is called a “tuff ring.”
These types of volcanoes in some cases are found in groups and are usually associated with larger volcanoes.
Example.
- Paricutín with a height of 424 meters, was formed in 1943 about 320 kilometers west of Mexico City, being the youngest of the specimens.
- Koko Head tuff ring, located on Oaku Island, Hawaii.
Summary table of the types of volcanoes
In this article we divide volcanoes according to their shape and according to their activity, the following table summarizes all types of volcanoes.
| Types of volcanoes | Characteristic |
|---|---|
| Active volcanos | They have had at least one volcanic eruption in the last 10,000 years. |
| dormant volcanoes | They have not erupted in the last 10,000 years but they denote some volcanic activity that does not classify them as extinct |
| extinct volcanoes | They are those that have not erupted for more than 25,000 years and do not denote detectable volcanic activity. |
| shield volcano | They are shield-shaped volcanoes and are related to lavas of basic composition |
| caldera type volcano | They are volcanoes that have a very large caldera that is formed by the collapse of the volcano or by the destruction of the volcanic cone in a very explosive eruption. |
| volcanic calderas | They are related to the boiler-type tippers |
| stratovolcano or composite volcano | They are those that appear imposing in the mountain ranges in the form of a cone, they are quite high because they are formed by the continuous accumulation of volcanic materials. they are generally highly explosive. |
| volcanic dome | They are small rounded volcanic structures that form around volcanoes, they can erupt with high explosiveness. |
| cinder or slag cone | They are small volcanoes that are composed of ash and scoria. |