Types of volcanoes, When ash,
gas, and magma burst from below the surface of the Earth, geological formations
known as volcanoes are created. Their size, form, style of eruption, and the
kind of magma they spew are used to categorise them into several kinds. It is
essential to comprehend the many kinds of volcanoes in order to evaluate their
risks, forecast eruptions, and comprehend the dynamic processes of Earth. The
different kinds of volcanoes are explained in detail below:
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| different types of volcanoes |
1. Shield Volcanoes:
With their wide, gently sloping
slopes, shield volcanoes are named after the shields of warriors. Basaltic lava
flows that cover vast regions in thin layers are the main material from which
they are constructed. Long-distance flowing lava that solidifies after
hardening is produced by these usually non-explosive eruptions. Hotspots and
divergent plate borders, like those in Iceland and the Hawaiian Islands, are
frequent locations for shield volcanoes.
2. Stratovolcanoes (Composite
Volcanoes):
Tall, steep-sided cones called
stratovolcanoes are made of layers of volcanic ash, pyroclastic deposits, and
hardened lava flows that alternate. They show both effusive and explosive
eruption types and are linked to intermediate to felsic magma compositions.
Stratovolcanoes are characterised by their violent eruptions that produce
pyroclastic flows, ash clouds, and lahars. They frequently have a central vent
or crater at the summit. Notable instances are Mount Fuji in Japan and Mount
St. Helens in the United States.
3. Cinder Cone Volcanoes:
Cones with steep sides that are
formed from ejected volcanic pieces called cinders or scoria are called cinder
cone volcanoes. In the course of violent eruptions, these pieces gather around
a single vent to form a conical shape. Ash clouds and fire fountains are common
features of cinder cone eruptions, which are usually brief in duration. Cinder
cones can still be dangerous to neighbouring towns even though they are smaller
than other types of volcanoes. Examples are the United States' Sunset Crater and
Mexico's Paricutin.
4. Lava Domes (Volcanic Domes):
Mounds or steep-sided masses of
congealed lava that form around a volcanic vent are called lava domes. They
originate from the eruption of extremely viscous magma to the surface, which
blocks the effective discharge of gas and causes lava to build up close to the
vent. Lava domes can expand over time through multiple eruptions and are
frequently connected to stratovolcanoes. Lava dome eruptions can nevertheless
be dangerous because they can result in pyroclastic flows and dome collapses,
even though they are usually slow and non-explosive. A prime example is the
lava dome formed by Mount St. Helens following its 1980 eruption.
5. Calderas:
Large, basin-shaped depressions
known as calderas are created when the earth collapses after a volcanic
eruption. They may be linked to several forms of volcanic activity, such as
shield volcanoes, stratovolcanoes, and massive volcanic complexes. Their diameters
can vary from a few kilometres to tens of kilometres. Calderas can be created
by either a single, catastrophic eruption or by the ground gradually sinking
over time. Santorini Caldera in Greece and Yellowstone Caldera in the United
States are two examples of calderas.
6. Submarine Volcanoes:
Underwater volcanic vents and
structures, which frequently originate along mid-ocean ridges or hotspot paths,
are known as submarine volcanoes. Seamounts, undersea cones, and hydrothermal
vents are just a few of the shapes they can take. The creation of oceanic crust
and the worldwide cycle of elements and nutrients are both significantly
influenced by submarine volcanoes. They also have ties to distinct habitats
that are home to a variety of marine species. Axial Seamount in the Pacific and
the Gakkel Ridge in the Arctic are two instances of underwater volcanoes.
7. Supervolcanoes:
With a volcanic explosivity index
(VEI) of eight or greater, supervolcanoes are massive volcanic systems that are
capable of erupting in an extraordinarily enormous and explosive manner. The
massive amounts of gas, pyroclastic debris, and volcanic ash that are released
into the atmosphere during these eruptions have the potential to affect the
climate and environment worldwide. Vast magma chambers under the Earth's
surface and enormous calderas are features of supervolcanoes. Examples are the
Taupo Volcano in New Zealand, the Lake Toba Caldera in Indonesia, and the
Yellowstone Caldera in the United States.
8. Fissure Eruptions:
Fissure eruptions do not happen
at a single central vent, but rather along elongated fractures or fissures in
the Earth's crust. Lava fountains, lava flows, and volcanic gases that erupt
along the fissure are the features that most often link them to basaltic magma.
As demonstrated by the Deccan Traps in India and the Columbia River Basalt
Group in the northwest of the United States, fissure eruptions can produce vast
lava fields and lava plateaus.
9. Cryptodomes:
Lava is extruded beneath the
Earth's surface, creating volcanic structures known as cryptodomes that cause
the rocks above to be uplifted and distorted. Although cryptodomes may not
break the surface, they can nonetheless pose a serious risk to geological
stability and produce major ground deformation and volcanic unrest, in contrast
to lava domes, which are visible at the surface. Frequently occurring before
volcanic eruptions, cryptodomes are linked to the seepage of viscous magma into
shallow crustal reservoirs. As an illustration, consider the cryptodomes that
were seen during Mount St. Helens' 1980 eruption.
10. Maars:
Maars are broad, shallow craters
created by violent phreatomagmatic eruptions that happen when magma comes into
contact with surface or groundwater. A crater full of water and volcanic ash is
formed by the steam explosions produced by these eruptions, which also shatter
the nearby rocks. Maars are usually found in rift zones and volcanic
fields—volcanic areas with copious amounts of groundwater. The Zuni-Bandera
Volcanic Field in New Mexico, USA, and the Laacher See Maar in Germany are two
examples of maars.
Assessing volcanic hazards,
keeping an eye on volcanic activity, and reducing threats to infrastructure and
human populations all depend on an understanding of the wide variety of volcano
types. Understanding the behaviour of volcanoes is essential for public safety
and catastrophe planning, as they can display many levels of activity, ranging
from dormant to active to eruptive. We can better understand volcanic dangers
and reduce their negative effects on the environment and society by conducting
ongoing study on volcanic processes and monitoring methods.
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