Different Types of Volcano

Volcanoes are majestic landscapes that can wreck havoc when it erupts. Did you know that there six(6) different types of volcanoes? Here are the first three major types of volcanoes.

1. Shield Volcanoes

• very broad and gently sloping volcanoes; like a shield of a warrior.

• They generally have balsaltic lava: a type of lava that have very low amounts of silica, making if flow in great distances over the wide surface of the volcano.

• The slope of shield volcanoes is usually more than 10 degrees at its summit and 2 degrees at its base.

• Famous examples are Mauna Loa and Mt. Kilauea in Hawaii.

Mauna Loa in Hawaii (https://www.youtube.com/watch?v=i-3IrJYq2Ko)

2. Cinder Cone Volcanoes

• The steepest types of volcano, with slopes of 30 to 40 degrees

• The volcanoes vent ejects high gas-content lava into the air and gets broken into smaller fragments that solidify and fall as cinders around the vent to form a steep cone.

• Cinder cone volcanoes have bowl-shaped craters

• Famous cinder cone volcanoes include Mt. Paricutin in Mexico that grew in the middle of a corn field in 1943.

Mt. Paricutin in Mexico (http://www.lakepatzcuaro.org/PostCard6.html)

3. Composite Volcanoes (a.k.a. Stratovolcanoes)

• These volcanoes have the most symmetrical cone shapes of all types of volcanoes.

• They are built of alternating layers of lava and pyroclastic materials, thus the name “strata” meaning “layers”

• Its slope is up to 30 degrees at the summit and 5 degrees at the base.

• these volcanoes are formed by very viscous lava that can plug its throat. This plug in the throat of composite volcanoes can cause pressure to build up in the magma chamber, causing it to erupt in an explosive manner.

• Mt. Mayon in Albay and Mt. Pinatubo in Tarlac are some famous examples of active composite volcanoes in the Philippines. Other famous examples are Mt. St. Helens in the United States of America and Mt. Fuji in Japan.

Mt. Mayon in Albay (http://volcano.oregonstate.edu/mayon)

Mt. Fuji in Japan (https://japanbyjapan.com/discover/mount-fuji-5)

Mt. ST. Helens before it eruption in May 18, 1980 (https://volcanoes.usgs.gov/observatories/cvo/Historical/LewisClark/Info/summary_mount_st_helens.shtml)

Other Types of Volcanoes

1. Volcanic Domes

(Photo credit: USGS. 1984 USGS picture of the growing Mount St. Helens Lava dome. )

• Also known as lava domes, commonly occur within the craters or on the sides of large stratovolcanoes formed after a major eruption.

• Volcanic domes are rounded, steep-sided mounds built by lava too viscous to flow any great distance, like toothpaste out of a tube. This viscous lava piles over and around its volcanic vent

• Examples of lava domes include Mono Dome in California and Santiaguito Dome in Guatemala. After Mount St. Helens in the state of Washington erupted in May 1980, a lava dome began to form in its crater. Currently, the dome rises more than 900 feet (275 meters) above the crater floor.

2. Caldera

• A caldera is formed after a volcano erupts very violently. When almost emptying the content of its magma chamber after the eruption, the roof of the magma chamber becomes hallow and left unsupported, causing it to collapse on its own weight, forming a large , usually circular, steep-walled basin.

• Our Taal Volcano is an example of a caldera, with Tagaytay as a former part of its cone.

3. Lava Plateau

Columbian Plateau (https://www.britannica.com/science/lava-plateau

• In some eruptions, lava pours forth through fissures or long, narrow cracks in the ground instead of through a central vent in a volcano. This thin lava tends to spread out rapidly and widely, flooding the surrounding landscape. Repeated outpourings of lava eventually build up to create flat lava plains called lava plateaus

• Lava plateaus are also known as flood basalts, after the dark, dense volcanic rock called basalt that floods across the surface of the land. Although erupted in thin sheets, the lava flows accumulate to form deposits thousands of feet thick.