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The word lava comes from Italian and is probably derived from the Latin word labes, which means a fall or slide. [2] [3] An early use of the word in connection with extrusion of magma from below the surface is found in a short account of the 1737 eruption of Vesuvius, written by Francesco Serao, who described "a flow of fiery lava" as an analogy to the flow of water and mud down the flanks of ...
Flow banding is a geological term to describe bands or layers that can sometimes be seen in rock that formed from magma (molten rock). [ 1 ] Flow banding is caused by friction of the viscous magma that is in contact with a solid rock interface, usually the wall rock to an intrusive chamber or, if the magma is erupted, the surface of the Earth ...
Effusive basalt lava flows cool to either of two forms, ʻaʻā or pāhoehoe. [8] This type of lava flow builds shield volcanoes, which are, for example, numerous in Hawaii, [9] and is how the island was and currently is being formed.
A'a lava moves in a peculiar way—the front of the flow steepens due to pressure from behind until it breaks off, after which the general mass behind it moves forward. Pahoehoe lava can sometimes become A'a lava due to increasing viscosity or increasing rate of shear, but A'a lava never turns into pahoehoe flow. [11]
A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few metres wide and may be many kilometres long. Fissure vents can cause large flood basalts which run first in lava channels and later in lava ...
The thickness of a basalt lava, particularly on a low slope, may be much greater than the thickness of the moving lava flow at any one time, because basalt lavas may "inflate" by supply of lava beneath a solidified crust. [31] Most basalt lavas are of ʻAʻā or pāhoehoe types, rather than block lavas.
This causes enormous lava flows, accounting for 80% of Venus' surface area. Many of the mountains are large shield volcanoes that range in size from 150–400 km (95–250 mi) in diameter and 2–4 km (1.2–2.5 mi) high. More than 80 of these large shield volcanoes have summit calderas averaging 60 km (37 mi) across. [39]
A lava tube, or pyroduct, [1] is a natural conduit formed by flowing lava from a volcanic vent that moves beneath the hardened surface of a lava flow. If lava in the tube empties, it will leave a cave. Scientists have discovered fossils in lava tubes near Medina in northwestern Saudi Arabia, [2] encouraging the belief that both humans and ...