What type of lava does a stratovolcano have?
The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma.
What type of lava does Hekla have?
andesitic
The total volume of the 1970 Hekla lava is about 0.2 km3. The new Hekla lava is andesitic, containing a little olivine, and in chemical composition and texture similar to the lava produced during the last months of the 1947-48 eruption. The outer structure is typical aa lava.
Do stratovolcanoes erupt lava?
They are formed from viscous, sticky lava that does not flow easily. The lava therefore builds up around the vent forming a volcano with steep sides. Stratovolcanoes are more likely to produce explosive eruptions due to gas building up in the viscous magma.
Do Hawaiian volcanoes produce andesitic lava?
Hawaiian Volcanoes produce andesitic lava. Lava domes form when high viscosity magma with low volatile content cools quickly, forming a hardened dome a few meters to a kilometer or so in height. The higher the viscosity of a magma, the more fluid is its behavior.
What type of rocks do stratovolcanoes produce?
Usually constructed over a period of tens to hundreds of thousands of years, stratovolcanoes may erupt a variety of magma types, including basalt, andesite, dacite, and rhyolite. All but basalt commonly generate highly explosive eruptions.
Is Yellowstone the only supervolcano?
The Yellowstone Caldera, sometimes referred to as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States….
Yellowstone Caldera | |
---|---|
Age of rock | 2,100,000–70,000 years |
Mountain type | Caldera and supervolcano |
Volcanic field | Yellowstone Plateau |
Is Hekla convergent or divergent?
Hekla is located on the mid-ocean ridge, a diverging plate boundary.
Is Hekla volcano active?
Mount Hekla is located in the highly active volcanic zone along the south shore and is the most active volcano in Iceland with more than 20 eruptions since 874. The volcano is part of a volcanic ridge, 40 km (25 mi) long. The most active part of this ridge is a fissure about 5.5 km (3.4 mi) long named Heklugja.
What happens when stratovolcanoes erupt?
The stratovolcano’s eruptions of more-viscous lava are the explosive ones, ejecting volcanic rock (old lava) and fresh lava violently to produce both airborne pyroclastics, or tephra, and sweeping slides of fragments downslope.
What causes stratovolcanoes to erupt?
Explosive eruptions occur at stratovolcanoes due to the high gas concentration in the magma. As the magma rises, the gases release, causing the pressure beneath the volcano to increase. Once this pressure becomes large enough, an explosive eruption occurs.
What kind of lava is Hawaii made of?
olivine basalt
The commonest lava of all the Hawaiian volcanoes is the type known as olivine basalt. Its most abundant constituent is the light-colored mineral labradorite, which is a variety of plagioclase feldspar (see vocabulary page 60) containing more lime than soda. It generally comprises nearly half of the crystallized rock.
What is Hawaiian lava called?
Pahoehoe
Pahoehoe (pronounced “pah-hoy-hoy”) and aa (pronounced “ah-ah”) are the two main types of Hawaiian lava flows, and these two Hawaiian names, introduced into the scientific literature in the late 19th century, are now used by volcanologists worldwide to describe similar lava-flow types.
https://www.youtube.com/watch?v=KwGReC3_2C0