What is Lava?

Molten rock erupted to the Earth’s (or other planet’s) surface.

BASALTIC LAVA FLOWS

Why should I care?

Craters of the Moon

Lava Flows Are Mostly Considered An Oddity

75% of Earth’s Crust is LavaMost of it is beneath the oceans

Pāhoehoe and ‘A‘ā

‘A‘ā Lava Flows

Pāhoehoe Flows

Pāhoehoe Sheet Flows

May 1990

Shelly Pahoehoe

Pāhoehoe to ‘A‘ā Transition

WHY THE DIFFERENCE?

Lava Flows consist of a Fluid and Crust

• FLUID ––Viscosity or Stickiness of the Lava– Affected by temperature, water, composition

• CRUST––Shear Strain Rate or Tearing Force– Affected by ground slope and amount of lava