Earth's Surface Features

Students apply their knowledge of basic Earth materials and Earth’s structure to figure out how Earth’s surface is constantly changing because it is fragmented into slabs of rock called tectonic plates. The movement of these plates determines where the majority of Earth's landforms, including mountains, valleys, earthquakes, and volcanoes are located.

• Earth’s internal layers interact with one another because Earth’s crust is broken into drifting slabs of solid rock called tectonic plates. 
• The different movements of the tectonic plates change the surface of Earth. 
• There is a cause-and-effect relationship between the interactions of Earth’s tectonic plates and the presence and location of many of Earth’s landforms. 
• Earth’s crust forms the continents and holds the oceans. Continents are part of plates and there are tectonic plates underneath the ocean, even though we cannot see them.
• Tectonic plates move because they are pushed and pulled by the semi-solid magma that makes up Earth’s mantle and flows in currents beneath the crust.
• Surface features, such as mountains, valleys, and volcanoes, are caused by the movement of tectonic plates, and are therefore most common at fault lines (where Earth’s tectonic plates meet)
  
  

• How are tectonic plates, oceans, and continents interacting?
• How does Earth’s structure cause the tectonic plates to move?
• Why do tectonic plates make Earth’s crust look like a jigsaw puzzle?
• How do mountains and valleys form from plate movement?
• How is the movement of a transform plate boundary different from convergent and divergent plate boundaries?
• Why do earthquakes occur at all three types of plate boundaries?
• How does Earth’s structure cause volcanoes to erupt?
• Why do mountains, valleys, earthquakes, and volcanoes often occur in similar locations?
• How could the locations of various landforms and events such as volcanoes and earthquakes on Earth’s surface form a pattern?
  
  

Misconception: Weathering and erosion refer to the same process.

Fact: Weathering and erosion are two different processes that often work closely together (weathering breaks down rocks and erosion transports the sediment).

Misconception: Volcanoes and earthquakes are located randomly around Earth.

Fact: Volcanoes and earthquakes result from the movement of Earth’s tectonic plates, so their locations usually correspond to plate boundaries.

Erosion :  the transport of sediment by wind, water, or gravity

System :  a set of connected, interacting parts that form a more complex whole

Tectonic plates :  drifting slabs of solid rock, called plates, that make up Earth’s surface

Volcano :  a structure formed around a hole in Earth’s crust that releases magma

Weathering :  the breakdown of rock into smaller pieces from exposure to wind, water, changes in temperature, and/or biological forces; there are two kinds: mechanical and chemical

Erupting Volcanoes

People cannot travel to Earth’s interior. The deepest any machine has drilled into the planet is 12 kilometers (7 miles). We can only see diamonds that have been carried from the mantle to Earth’s surface by volcanic eruptions.

Volcanoes are structures formed around a hole in Earth’s crust that releases magma. Magma that reaches the surface during an eruption is called lava. Lava is liquid rock that turns into solid rock as it cools. The magma carries diamonds with it.

Scientists believe that the kinds of volcanoes that brought diamonds to the surface don’t occur anymore. Scientists think this is because Earth used to be much hotter. This resulted in volcanic eruptions that were very explosive. The erupting magma carried the diamonds, which had already formed, from the mantle to Earth’s surface very quickly—traveling 48-64 kilometers (30-40 miles) per hour.

Moving Plates

Volcanoes happen because Earth’s crust is broken into drifting slabs of solid rock called tectonic plates. The plates cause Earth’s surface to look like a jigsaw puzzle. Heat from Earth’s core causes the semi-solid rock of Earth’s mantle to rise and fall like ocean tides. As magma moves beneath the crust, it pushes the tectonic plates toward or away from each other. The places where Earth’s tectonic plates meet are called fault lines.

Plate Boundaries

The different movements of the tectonic plates change the surface of Earth. When two plates move toward one another perpendicular to the fault line, they form a convergent boundary. When two tectonic plates collide at a convergent boundary, the force is very powerful. It can cause the land to be uplifted, forming mountain ranges and volcanoes, as well as earthquakes.

Sometimes two plates move apart from one another perpendicular to the fault line. These plates form a divergent boundary. This movement can create ocean trenches, valleys, earthquakes, and places where magma wells up onto Earth’s surface.

Transform boundaries are formed when two plates slide past each other in parallel, grinding along their sides as they go. This motion can cause earthquakes.

Active Volcanoes

Sometimes, the movement of the tectonic plates causes holes, called vents, to open up in Earth’s crust. The vents allow magma from the mantle to seep through. This is how volcanoes form.

Volcanoes can be active, dormant, or extinct. It depends on how close the crack in Earth’s surface is to an available pool of magma in the mantle, called the magma chamber. An active volcano erupts at least once every 10,000 years. A dormant volcano hasn’t erupted in the past 10,000 years, but is expected to again. An extinct volcano is expected to never erupt again. A volcano can become dormant or extinct if the movement of tectonic plates carries it away from its source of magma.

Landforms Patterns

The majority of landforms on Earth’s surface have formed because of the movement of the tectonic plates. Because of this, mountains, valleys, and volcanoes are common at fault lines. Earthquakes are also common at fault lines. If two plates get stuck together, they build up energy until they can break apart. Earthquakes are the vibrations felt when tectonic plates gather enough energy to move past one another.

Earthquakes occur all over the world at all three kinds of plate boundaries: convergent, divergent, and transform. Volcanoes are most common along divergent and convergent boundaries.

One of the most well-known plate boundaries encircles the Pacific Ocean. It is often called the Ring of Fire because so many earthquakes and volcanic activity occur here. The Ring of Fire has more than 450 active volcanoes.

In this lesson, students figure out the phenomena of volcanic eruptions at plate boundaries by examining the locations of earthquakes and volcanoes on a world map to analyze their distribution patterns relative to Earth’s tectonic plates. Students use the patterns they observe in the earthquake, volcano, and tectonic plate boundaries to map and describe their predictions for why these patterns occurred.