The viscosity and gas content of a magma determines how it erupts. Low viscosity and low gas content generally lead to quiescent eruptions. What are the two primary factors that determine the manner in which magma erupts?
Pyroclastic flows primarily contain pumice, vesicular pyroclastic material, and _______. Magma tends to rise toward Earth's surface principally because __________.
Resistance to flow. Magma has a higher viscosity if it has a lower temperature, is rich in silica, and contains very few dissolved gases. Define viscosity.
The eruption was so large that the magma chamber under Crater Lake partially emptied, causing the volcano to become unstable and collapse. In addition to rock deposits, what evidence do we have that the eruption that preceded the formation of Crater Lake was very large? The volcano is still active, and a new volcanic peak has formed.
geo quiz 6QuestionAnswerWhich type of basaltic lava flow has a fairly smooth, unfragmented, ropy surface?pahoehoe________ is a major dissolved volatile constituent in both magmas and volcanic gases.WaterVolcanic bombs originate ________.as erupted magma blobs that partly congeal before falling to the ground65 more rows
Pahoehoe lava flows are fed almost… … world by their Hawaiian names: pahoehoe, a more fluid flow with a smooth to ropy surface; and aa (or a'a), a more viscous flow whose surface is covered by thick, jumbled piles of loose, sharp blocks. Both types have the same chemical composition; the difference seems to be in the…
Pahoehoe, ropy lava that forms as non-viscous lava, flows gently, forming a skin that gels and then wrinkles because of ongoing flow of the lava below the surface (Figure 4.19b, and “lava flow video”).
Such a surface is called ropy pahoehoe. In addition to these ropy surfaces, solidified basalt flows can also display shelly to slabby surfaces. Shelly pahoehoe contains a billowy flow top with a frothy vesicular surface skin, only a few centimeters thick, overlying large cavities, generally 5-30 centimeters thick.
Pahoehoe"Pahoehoe" is a Hawaiian word used to describe a lava flow with a smooth, ropy surface. Pahoehoe flows advance slowly, with small amounts of lava squeezing out of a cooler crust. Pahoehoe flows can exhibit all kinds of different shapes as they form and cool. These are sometimes called "lava sculpture."
Definition of ropy lava : lava marked with wrinkles resembling rope : pahoehoe.
Rhyolitic lavas are viscous and tend to form thick blocky lava flows or steep-sided piles of lava called lava domes. Rhyolite magmas tend to erupt explosively, commonly also producing abundant ash and pumice.
Lavas, particularly basaltic ones, come in two primary types: pahoehoe (pronounced 'paw-hoey-hoey") and aa (pronounced "ah-ah"). Both names, like a number of volcanological terms, are of Hawaiian origin. A third type, pillow lava, forms during submarine eruptions.
Lava erupting on the deep sea floor has a form most like pahoehoe flows. Threetypes of lava flows are common on the sea floor: pillow lava, lobate lava, andsheet lava.
This is a large piece of a type of basaltic lava flow known by the Hawaiian word "pāhoehoe" (pronounced "pah-hoy-hoy"). Basalt is the most common type of volcanic rock. A pāhoehoe flow is distinguished by its smooth, hummocky, or ropy surface, and is a result of gas-poor magma.
Pahoehoe is lava that in solidified form is characterized by a smooth, billowy, or ropy surface, while aa is lava that has a rough, jagged, spiny, and generally clinkery surface. In thick aa flows, the rubbly surface of loose clinkers and blocks hides a massive, relatively dense interior.
Smooth Lava: Pahoehoe Pahoehoe lava flows are formed from eruptions that are not very violent, but that slowly extrude lava. This tells us something about what the lava flow is made of and how easily it flowed over the surface.