GEOLOGY

Detailed explanation-1: -Molten lava flows are relatively high-viscosity liquids, and most of them advance slowly (a few metres per minute to less than a metre per day).

Detailed explanation-2: -Fluid basalt flows can extend tens of kilometers from an erupting vent. The leading edges of basalt flows can travel as fast as 10 km/h (6 mph) on steep slopes but they typically advance less than 1 km/h (0.27 m/s or about 1 ft/s) on gentle slopes.

Detailed explanation-3: -Pahoehoe forms when lava flows more slowly.

Detailed explanation-4: -If lava cools slowly and does not move too fast it forms smooth ropy lava called pahoehoe.

Detailed explanation-5: -Lava has been clocked within a channel at nearly 35 mi/hr or 15 m/s during the1984 Mauna Loa eruption and similarly in channels during the first years of Pu‘u ‘O‘o. Within the current tube system, lava speeds have been measured up to 23 mi/hr, or 10 m/s.