Geology: Earthquakes and Plate Tectonics

Study Notes

The Richter Scale measures earthquake magnitude, with larger numbers indicating stronger earthquakes.
Each whole number increase on the Richter scale represents a tenfold increase in ground shaking and a 32-fold increase in energy released.
Earthquakes are often caused by plates sliding past each other at transform boundaries, such as the San Andreas Fault in California.
Seismic waves are vibrations that travel outward from the focus, the point where an earthquake's energy is released.
The epicenter is the point on Earth's surface directly above the focus.

Plate tectonics is the theory explaining the movement of Earth's lithospheric plates.
The lithosphere is composed of the crust and upper mantle, and floats on the partially molten asthenosphere.
Plate boundaries are where plate interactions occur, leading to various geological features.

Divergent boundaries occur when plates move apart, allowing magma to rise and form new crust. This process is responsible for mid-ocean ridges, rift valleys, and volcanic activity.
Convergent boundaries occur when plates collide, resulting in subduction, where one plate sinks beneath another. This process leads to volcanoes, earthquakes, and mountain ranges.
Transform boundaries occur when plates slide past each other, causing earthquakes and faults.

Seafloor spreading is the process by which new oceanic crust is created at mid-ocean ridges and spreads away from the ridge.
Basalt, a type of igneous rock, is formed as magma rises and cools along mid-ocean ridges.

Convection currents in the Earth's mantle are driven by uneven heating, creating a cycle of hot, less dense material rising and cooler, denser material sinking.
These convection currents are responsible for the movement of tectonic plates.