GEOLOGY

Detailed explanation-1: -If lava cools slowly and does not move too fast it forms smooth ropy lava called pahoehoe. However, if it cools quickly and moves fast it can tear into clinkery pieces called a’a. Temperature and gases certainly influence whether the lava becomes aa or pahoehoe.

Detailed explanation-2: -Pahoehoe (Pa-Hoy-Hoy) lava flows are very hot, thin and runny. When it cools is has a smooth to ropey texture because of the low silica content which makes it cool quickly. Pahoehoe flows creep along generally at less than 3 feet per minute but some flows have been measured at over 20 miles per hour.

Detailed explanation-3: -Basaltic lava flows move much faster than rhyolitic lava flows. Also, the amount of gas dissolved in the lava can change the flows ability to flow (viscosity). The rate of material that the vent is spewing out. During some eruptions vast amounts of lava are released and so the flows tend to be faster.

Detailed explanation-4: -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].

Detailed explanation-5: -known by the Hawaiian names pahoehoe and aa (or a’a). 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.