Plate tectonics

2. hot molten or semifluid rock erupted from a volcano or fissure that has reached the surface outside of the Earth's crust
6. a sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth's crust or volcanic action.
8. when there is a sudden outbreak from a volcano
10. plates slide past each other in opposite directions, or in the same direction but at different speeds
11. This plate boundary is formed when oceanic and continental plates move together. The oceanic plate is forced under the lighter continental plate. Friction causes melting of the oceanic plate and may trigger earthquakes.
12. when two continental plates collide. Neither plate is forced under the other, and so both are forced up and form fold mountains

1. molten rock stored in the Earth's crust
3. explains the features and movement of Earth's surface in the present and the past
4. a type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris, and water.
5. a long high sea wave caused by an earthquake
7. This plate boundary is formed when plates move apart. Volcanoes are formed as magma wells up to fill the gap, and eventually new crust is formed
9. a type of excavation or depression in the ground that is generally deeper than it is wide, and narrow compared with its length.