Is pahoehoe lava thick or thin?
Pahoehoe lavas are typically the first to erupt from a vent. They are relatively thin (1-2 m) and very fluid with low viscosities. They advance downslope in a sort of smooth “rolling motion.” The front of the flow usually advances as a thin (< 20 cm) glowing lobe that will chill and crust over after 1-2 meters of flow.
Is pahoehoe lava mafic or felsic?
Mafic lava, which forms much of the oceanic crust, is high in magnesium and iron. Mafic lava is primarily responsible for forming the Hawaiian Islands. Two common forms of mafic lava flow are known by their Hawaiian names: pahoehoe and aa. Pahoehoe lava is billowy lava that is often wrinkled and ropy in appearance.
What is the viscosity of pahoehoe lava?
Minimal viscosities of lava of the ‘a’a lobes ranged from 1.3 × 105 to 3.3 × 107 Pa s (flow rate method), and those of the pahoehoe from to 5 × 103 to 5 × 104 Pa s (shear stress method).
Is pahoehoe lava runny?
The most common subaerial lava flows today are pahoehoe, aa, and blocky lavas. Lava surface is cooling very rapidly.
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).
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.
What are the two types of lava called?
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.
What is highly viscous?
A fluid that is highly viscous has a high resistance (like having more friction) and flows slower than a low-viscosity fluid. To think of viscosity in everyday terms, the easier a fluid moves, the lower the viscosity. Honey would move slower than water, so honey would have a greater viscosity.
Can a human outrun lava?
Could I outrun the lava and make it to safety? Well, technically, yes. Most lava flows — especially those from shield volcanoes, the less explosive type found in Hawaii — are pretty sluggish. As long as the lava doesn’t find its way into a tube- or chute-shaped valley, it will probably move slower than a mile per hour.
Can you outrun basaltic lava flow?
On a flat slope, its basaltic lava moves no faster than 10 kilometers (6.2 miles) per hour. This is slightly faster than walking pace, but it’s a safe bet that you would be able to outrun it.
Can you walk on pahoehoe lava?
Walking is easy on the pahoehoe lavas. On the coastal platform, high fluidity lava traveled over a smooth, flat surface, where it ponded and formed a smooth solidified crust.
Why is it called aa lava?
There are several different kinds of lava, depending on the chemical composition and temperature of the molten rock that erupts from a volcano. The smooth variety is called pahoehoe, and the rougher variety is known as a’a (pronounced ah-ah). A’a is a Hawaiian word meaning “stony with rough lava”.