Plate Tectonics Theory

1. A convergent boundary is one type of plate boundary. In this boundary two or more tectonic plates move towards each other.

1.1. A subduction zone is when one tectonic plate sinks beneath another forming landforms such as volcanoes.

1.2. A trench is an area on the ocean floor where it dips down. These are formed at convergent boundaries.

2. At divergent boundaries two or more plates move away from each other.

2.1. A rift is a break in rock. These form at divergent boundaries when two plates pull away.

2.2. Ridges are raised areas of land formed when two tectonic plates slide down and move away.

3. Plate boundaries are the areas where tectonic plates meet. The three types are convergent, divergent, and transform.

4. Crust is the outer part of the Earth that makes up tectonic plates. There are two types of crust, oceanic and continental.

4.1. Oceanic crust is exactly what it sounds like, crust found in the ocean that is denser.

4.2. Continental crust is crust that is less dense.

5. The final type of boundary is a transform boundary in which plates slide past one another. California is on a transform boundary.

5.1. Faults are cracks in the crust where energy builds up and releases over time. These occur at transform boundaries. California is very well known for the San Andreas Fault.

5.2. Earthquakes are created when the energy at faults is released and the land shifts. California's biggest earthquake registered at at 7.9 on January 9th, 1857. Source- National Geographic

6. Tectonic Plates are moving pieces that make up the Earth's crust. These plates use the lithosphere to move. California is part of the North American plate.

6.1. Lithosphere is the are of the crust and upper mantle. This is created at divergent boundaries.

6.2. When three tectonic plates meet up together it is called a triple junction. There is a triple junction near California between the North American plate, the Pacific plate and the Gorda plate.