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An eruption column or eruption plume is a cloud of super-heated ash and tephra suspended in gases emitted during an explosive volcanic eruption. The volcanic materials form a vertical column or plume that may rise many kilometers into the air above the vent of the volcano.
A Vulcanian eruption is a type of volcanic eruption characterized by a dense cloud of ash-laden gas exploding from the crater and rising high above the peak. They usually commence with phreatomagmatic eruptions which can be extremely noisy due to the rising magma heating water in the ground. This is usually followed by the explosive clearing of ...
The types of minerals present in volcanic ash are dependent on the chemistry of the magma from which it erupted. Considering that the most abundant elements found in silicate magma are silicon and oxygen, the various types of magma (and therefore ash) produced during volcanic eruptions are most commonly explained in terms of their silica content.
A volcano on the Alaska Peninsula erupted with little advanced warning over the weekend, spewing an ash cloud up to 20,000 feet high.
The longer eruptions begin with production of clouds of volcanic ash, sometimes with pyroclastic surges. The amount of magma ejected can be so large that it depletes the magma chamber below, causing the top of the volcano to collapse, resulting in a caldera. Fine ash and pulverized pumice can be deposited over large areas.
Mount Ruang spewed lava and and ash on April 17, seen from Sitaro, North Sulawesi. It also triggered lightning in the ash cloud -- a common phenomenon in powerful volcano eruptions.
A volcanic eruption is one of the most powerful forces in nature, a seemingly unstoppable phenomenon that can have far-reaching impacts far beyond the area surrounding the volcano itself. When a ...
These eruptions produce rhyolitic lava, tephra, pumice and thick pyroclastic flows that cover vast areas and may produce widespread ash-fall deposits. Examples are Mt. Mazama and Yellowstone. Phreatomagmatic eruptions (hydrovolcanic) are characterized by interaction of rising magma with groundwater.