Plate Tectonics and Boundaries

• Earth's outermost layer is called the crust.
• Tectonic plates are large segments of Earth's crust that move slowly over time.
• The three types of plate boundaries are convergent, divergent, and transform.

Plate Boundaries

• At divergent boundaries, plates move apart, resulting in the creation of new land or crust, such as at mid-ocean ridges.
• When an ocean plate and a land plate converge, the ocean plate subducts beneath the land plate, leading to the formation of volcanoes and mountains.
• At transform boundaries, plates slide past each other, which results in earthquakes.

Plate Movement

• Convection currents, driven by heat within the Earth, cause tectonic plates to move.
• Tectonic plates float on the asthenosphere, a soft layer in the Earth's mantle.
• Subduction is the process where one plate slides beneath another.

Natural Disasters and Features

• Plate boundaries are often sites of earthquakes, volcanoes, and tsunamis.
• The Ring of Fire, located around the Pacific Ocean, is characterized by high volcanic and seismic activity.
• Hotspots are locations where magma rises to the surface, forming volcanoes independent of plate boundaries.
• The Himalayas were formed by the collision of two land plates.
• The San Andreas Fault is an example of a transform plate boundary.

Additional Facts

• Evidence supporting the movement of tectonic plates includes the puzzle-like fit of continents and the presence of identical fossils on different continents.
• Sea-floor spreading is when new crust is generated beneath the ocean at divergent plate boundaries.
• Tectonic plates shape the Earth's surface by forming mountains, valleys, causing earthquakes, and creating volcanoes.
• Millions of years ago, the Earth's continents were joined in a supercontinent called Pangaea.
• Studying plate tectonics helps in understanding natural disasters and Earth's long-term geological changes.