Earth's Layers
This is the solid part of Earth including rocks, minerals, and landforms.
The Geosphere
This ancient supercontinent existed about 225 million years ago before it broke apart.
Pangaea
On March 11, 2011, this country was struck by a 9.0 magnitude earthquake that triggered a massive tsunami and caused a nuclear power plant meltdown
Japan
When magma reaches Earth's surface, it is called this
Lava
This type of rock forms when sediment layers are compacted and cemented together over time. It often contains fossils.
Sedimentary rock
Scientists use these vibrations, sent through the planet by earthquakes, to learn what is inside Earth.
Seismic Waves
At this type of boundary, plates move APART and new crust forms through seafloor spreading.
A divergent boundary
About 80% of all earthquakes happen in this zone surrounding the Pacific Ocean.
Ring of Fire
Most volcanoes form at plate boundaries where this melted rock can break through the crust.
Magma
This type of rock is formed when existing rock is changed by heat and pressure but is NOT melted. Marble is an example.
Metamorphic Rock
This is the only liquid layer inside Earth. It is made of iron and nickel.
Outer Core
This is the process where oceanic crust sinks under a continental plate and melts back into magma.
Subduction
This is the place where an earthquake starts underground.
The focus
this chain of volcanic islands can be found in the Pacific Ocean
Hawaiian islands
These types of rocks cools quickly at the surface forming tiny crystals or no crystals
Extrusive Igneous Rocks
Tectonic plates float on top of this hot, semi-liquid zone in the upper mantle.
The asthenosphere
This is the name for the border between two tectonic plates where most of Earth's major geological events — volcanoes, earthquakes, and mountain-building — occur.
Plate Boundary
This instrument records seismic waves and draws a zigzag line called a seismogram.
A seismograph
This broad, gently sloping volcano is built from fluid lava that flows easily over large distances.
Shield Volcano
This type of igneous rock cools slowly underground, forming large crystals. Granite is an example.
Intrusive igneous rock
This type of crust is thinner (~7 km), younger, and denser than the crust found under the continents.
Oceanic crust
This is the name for the underwater mountain range that forms when magma fills the space between two diverging plates on the ocean floor.
Mid-Ocean Ridge
On the Richter scale, each increase of 1 means the earthquake is how many times stronger
10 times stronger
There are about this many active volcanoes on Earth
1900
About this many people live within the danger range of an active volcano
350,000
(350 million)