Search results
Results from the WOW.Com Content Network
Hydrothermal circulation in the oceans is the passage of the water through mid-oceanic ridge systems.. The term includes both the circulation of the well-known, high-temperature vent waters near the ridge crests, and the much-lower-temperature, diffuse flow of water through sediments and buried basalts further from the ridge crests. [3]
A prime example is the Sakurajima eruption in 1914 (approximately 1.5 km 3 in volume), which caused the magma chamber to sink 60 cm. 58 people were killed in the eruption. [4] For this amount of magma to erupt, it would take approximately 130 years for the chamber to refill as according to Dr James Hickey and his co-authors.
A scheme of a phreatic eruption: 1: water-vapor cloud, 2: magma conduit, 3: layers of lava and ash, 4: stratum, 5: water table, 6: explosion, 7: magma chamber Phreatic eruption at the summit of Mount St. Helens, Washington, in the spring of 1980
Like all Hawaiian volcanoes, Mauna Loa was created as the Pacific tectonic plate moved over the Hawaii hotspot in the Earth's underlying mantle. [10] The Hawaii island volcanoes are the most recent evidence of this process that, over 70 million years, has created the 3,700 mi (6,000 km)-long Hawaiian–Emperor seamount chain. [11]
The last and the most trivial cause for magma eruption is an injection of fresh magma from lower parts of the crust into the issued magma chamber, which increases the content of the liquid phase, and consequently, the pressure inside the chamber, which is concurrently released as a flux of lava onto the earth surface.
The volcano is fed by a magma chamber under the mountain, which in turn derives from the tectonic divergence of the Mid-Atlantic Ridge. It is part of a chain of volcanoes stretching across Iceland. Its nearest active neighbours are Katla, to the northeast, and Eldfell, on Heimaey, to the southwest. [12]
The process powering Plinian eruptions starts in the magma chamber, where dissolved volatile gases are stored in the magma. The gases vesiculate and accumulate as they rise through the magma conduit. These bubbles agglutinate and once they reach a certain size (about 75% of the total volume of the magma conduit) they explode.
Plutonism is the geologic theory that the igneous rocks forming the Earth originated from intrusive magmatic activity, with a continuing gradual process of weathering and erosion wearing away rocks, which were then deposited on the sea bed, re-formed into layers of sedimentary rock by heat and pressure, and raised again.