Table of Contents
What makes a volcano erupt more violently?
A volcano’s explosiveness depends on the composition of the magma (molten rock) and how readily gas can escape from it. As magma rises and pressure is released, gas bubbles (mainly of water vapor and carbon dioxide) form and expand rapidly, causing explosions.
Which type of magma is more likely to have more dissolved gases?
The amount of gas in a magma is also related to the chemical composition of the magma. Rhyolitic magmas usually have higher gas contents than basaltic magmas.
Are most volcanic eruptions violent?
Effusive eruptions consist of a gentle and steady flow of lava on the surface, while explosive eruptions are violent phenomena that can eject hot materials up to several kilometres into the atmosphere. …
What type of volcanic eruption which is very violent due to the contact between water and magma?
Mauna Loa Volcano, Hawaii, 1950. Kilauea Volcano, Hawaii, 1959. “Phreatic” (or steam-blast) eruptions are driven by explosive expanding steam resulting from cold ground or surface water coming into contact with hot rock or magma.
What volcano has the most violent eruptions?
The most violent eruption registered in history was that in the La Garita Caldera in the United States. It occurred 2.1 million years ago and formed a 35 x 75 km crater, drastically changing the climate on Earth.
Which volcanic eruption is the most violent eruption?
Mt Tambora, Indonesia, 1815 (VEI 7) Tambora is the deadliest eruption in recent human history, claiming the lives of up to 120,000 people. On 10 April 1815, Tambora erupted sending volcanic ash 40km into the sky.
Which magma composition causes the most violent volcanic eruptions Why?
Explosive eruptions are favored by high gas content & high viscosity magmas (andesitic to rhyolitic magmas). The explosive bursting of bubbles fragments the magma into clots of liquid that cool as they fall through the air. These solid particles become pyroclasts or volcanic ash.
What kind of eruption does a volcano have?
Many eruptions are relatively quiescent and are characterized by the calm, nonviolent extrusion of lava flowson the earth’s surface. Other eruptions, however, are highly explosive and are characterized by the violent ejection of fragmented volcanic debris, called tephra,which can extend tens of kilometers into the atmosphere above the volcano.
How does the magma of a volcano work?
The magma types vary from mafic magmas, which have relatively low silica and high Fe and Mg contents, to felsic magmas, which have relatively high silica and low Fe and Mg contents. Mafic magma will cool and crystallize to produce the volcanic rock basalt, whereas felsic magma will crystallize to produce daciteand rhyolite.
How does the amount of dissolved gases in magma affect its viscosity?
The amount of dissolved gasesin the magma can also affect it’s viscosity, but in a more ambiguous way than temperature and silica content. When gases begin to escape (exsolve) from the magma, the effect of gas bubbles on the bulk viscosity is variable.
How does gas get out of a volcano?
The dissolved gases can escape only when the vapor pressureof the magma is greater than the confining pressureof the surrounding rocks. The vapor pressure is largely dependent on the amount of dissolved gases and the temperature of the magma. Gas escape through vertical vesicle cylinders