Search results
Results From The WOW.Com Content Network
Effusive eruption differs from explosive eruption, wherein magma is violently fragmented and rapidly expelled from a volcano. Effusive eruptions are most common in basaltic magmas, but they also occur in intermediate and felsic magmas. These eruptions form lava flows and lava domes, each of which vary in shape, length, and width. [2]
These eruptions are quiet because of the low viscosity of the lava and the small amount of trapped gases. The resulting sheet lava flows may be extruded from linear fissures or rifts or gigantic volcanic eruptions through multiple vents characteristic of the prehistoric era which produced giant flood basalts .
The terms lava stone and lava rock are more used by marketers than geologists, who would likely say "volcanic rock" (because lava is a molten liquid and rock is solid). "Lava stone" may describe anything from a friable silicic pumice to solid mafic flow basalt, and is sometimes used to describe rocks that were never lava, but look as if they ...
Diagram of the Yellowstone Caldera. The Lava Creek eruption of the Yellowstone Caldera, which occurred 640,000 years ago, [37] ejected approximately 1,000 cubic kilometres (240 cu mi) of rock, dust and volcanic ash into the atmosphere. [3] It was Yellowstone's third and most recent caldera-forming eruption.
Some of the eruptive structures formed during volcanic activity (counterclockwise): a Plinian eruption column, Hawaiian pahoehoe flows, and a lava arc from a Strombolian eruption. Several types of volcanic eruptions—during which material is expelled from a volcanic vent or fissure—have been distinguished by volcanologists.
And Mauna Loa, the world's largest active volcano, "put on a weeks-long show at the end of last year as it erupted for the first time in four decades, with lava fountains 60 meters high that sent ...
Later, but not precisely dated, eruptions from the Lassen volcanic area have formed over 30 smaller steep-sided, mound-shaped accumulations of volcanic rock, called lava domes. [4] Crescent Crater, which at first glance appears as a parasite on Lassen's northeast flank, has been more heavily glaciated and thus is older. [31]
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 ...