8.E.5B.2 Construct explanations of how forces inside Earth result in earthquakes and volcanoes.

Convection currents in the mantle result in the movement of lithospheric plates. The motion and interactions of the plates can create patterns in the location of volcanoes and earthquakes that result along the plate boundaries. The resulting activity that happens along the plate boundaries depends on the type of plate boundary being created (divergent, convergent, and transform) and the forces associated with those boundaries (compression, tension, and shearing).

Lithospheric Plate Motion and Seismic Activity Earthquakes occur along plate boundaries where tectonic forces result in the formation of faults and the buildup of pressure. When this built up pressure is released, an earthquake results along this fault line. Earthquakes can also occur along faults Scientists can specifically identify the type of boundary and fault that occurs along the edges of the plates by examining plate boundary maps. Scientists can also use seismic data to understand the ways in which the plates are moving and the relationship between seismic activity and lithospheric plate motion

Lithospheric Plate Motion and Volcanic Activity There is scientific data supporting abundant volcanism occurrences at divergent and convergent plate boundaries and a lack of volcanism associated with transform plate boundaries. Volcanic activity at divergent plate boundaries occurs as the plates pull apart which allows magma to fill the rift zone between the separating plates. Volcanic activity at convergent plate boundaries occurs as the two plates converge on one another. The leading edge of the subducted plate melts and rises through the overlying crust resulting in the formation of a volcanic chain of mountains. The most volcanically active belt on Earth is known as the Ring of Fire, a region of volcanic activity that happens at subduction zones surrounding the Pacific Ocean. Volcanic eruptions are constructive in that they add new rock to existing land and form new islands. Volcanic eruptions can be destructive when an eruption is explosive and changes the landscape of and around the volcano. Magma that reaches Earth’s surface is known as lava.

The specific types of volcanism that happens at divergent and convergent plate boundaries are called spreading center volcanism and subduction zone volcanism Intraplate volcanism is another term to describe the presence of volcanic activity over hot spots Specific surface features created from lithospheric plate motion include the Mid- Atlantic Ridge, Mariana trench, and the Aleutian trench