Warm Up 1. What is a convection current? 2. How does convection cause a lithospheric plate to move? Time’s Up!

VOLCANIC BOUNDARIES

Convergent Boundary Plates collide Continental- continental ◦ Create mountains Continental-oceanic ◦ Oceanic sinks ◦ Subduction zone and trench ◦ Remelted, recycled Oceanic-oceanic ◦ One subducts

Convergent Boundaries Subduction ◦ Oceanic subducted ◦ Produces magma Magma rises to form volcano

Explosive Eruptions Rare Destructive Produce clouds of ◦ Debris ◦ Ash ◦ Gas

Pyroclastic Flows Produced in small amounts of time, large amounts of material Lahar = volcanic mud flow Faster than a hurricane Temperatures greater than 700 deg. Celsius Deadly

Divergent Boundaries Rift zone ◦ Filled by magma Mid-ocean ridges ◦ Most volcanic activity ◦ Iceland, island of Surtsey

Nonexplosive Eruptions Most common Produce ◦ Calm lava flows ◦ Huge amounts of lava Shape our world ◦ Islands in the Pacific ◦ Sea floor ◦ NW U.S.