What is a pahoehoe flow?
What is a pahoehoe flow?
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.”
Is pahoehoe fast moving?
Pahoehoe lava is smooth and can have a ropy, billowy appearance. It’s low in viscosity, the measure of fluid thickness, and generally moves slowly.
What are the differences between pahoehoe and aa?
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.
What are the characteristics of pahoehoe lava flows?
Pahoehoe lava flows are characterized by smooth, gently undulating, or broadly hummocky surfaces. The liquid lava flowing beneath a thin, still-plastic crust drags and wrinkles it into tapestry-like folds and rolls resembling twisted rope.
How is pahoehoe formed?
Pahoehoe forms when lava flows more slowly. Under these circumstances, a well-developed skin can form which inhibits heat loss. When a tear in the skin does form, it is readily healed. Both magma discharge rate and the steepness of the slope over which the lava flows affect the flow rate.
Is pahoehoe faster than aa?
Pahoehoe lava flow is usually at least 10 times slower than typical aa lava flow5. Higher effusion rate results in lava flow being shattered which is how the rubbly and clinkery aa lava surface forms.
Which is faster pahoehoe or aa?
What is the difference between Pahoehoe and AA? Pahoehoe lava cools slowly while AA lava cools quickly. AA lava moves fast whereas Pahoehoe moves slowly. In the case of AA lava flow, gases have escaped from the upper surface creating clinkers and jagged outer structure.
What are the differences between pahoehoe and aa what kind of eruption produces these types of lava?
The pahoehoe flow has a comparatively smooth or “ropy” surface. The surface of the aa flow consists of free chunks of very angular pieces of lava. This difference in form reflects flow dynamics. Aa forms when lava flows rapidly.
How does Pahoehoe lava form?
How fast does Pahoehoe lava flow?
Pahoehoe flows are associated with low-effusion rate eruptions and are emplaced at low volumetric flow rates (2-5 cubic meters per second) and slow flow front velocities (1-10 m/hour) [See the A’a page for a velocity comparison chart]. Pahoehoe flows can be just as long as ‘a’a flows.
Does pahoehoe have high viscosity?
What type of lava flows the fastest?
PAHOEHOE – has a shiny, smooth, glassy surface. It tends to be more fluid (lower viscosity), hence flows more quickly and produces thinner flows (typically 1-3 m).
Which lava type flows the fastest?
How are pahoehoe rocks formed?
Pahoehoe forms where cooling basaltic lava will spread out as it erupts from the volcano. A thin elastic skin will congeal on the surface of the lava.
How does pahoehoe lava form?
How fast does pahoehoe lava flow?