Earthquakes: Types and Causes

A sudden release of energy in the Earth's crust, causing seismic waves to propagate through the Earth or along its surface
Caused by movement along faults, volcanic activity, or human activities such as injection of fluids into the ground

Tectonic earthquakes: result from movement along faults, plate boundaries, and plate tectonics
Volcanic earthquakes: caused by movement of magma and gas beneath a volcano
Collapse earthquakes: result from collapse of underground caverns or voids
Human-induced earthquakes: caused by human activities such as injection of fluids, mining, and construction

Magnitude: measure of the size of an earthquake, usually measured on the moment magnitude scale (Mw)
Intensity: measure of the effects of an earthquake at a particular location, usually measured on the Modified Mercalli Intensity Scale (MMI)
Depth: distance from the Earth's surface to the earthquake's epicenter
Epicenter: point on the Earth's surface directly above the earthquake's hypocenter (focus)
Hypocenter: location of the earthquake's focus, where the seismic waves originate

P-waves: primary waves, compressional waves that travel through the Earth's crust and mantle
S-waves: shear waves, waves that travel through the Earth's crust and mantle, but not through the core
Surface waves: waves that travel along the Earth's surface, causing the most damage

Seismometers: instruments that detect and record seismic waves
Seismographs: records of seismic waves, used to determine earthquake characteristics
GPS: Global Positioning System, used to measure ground deformation and movement

Ground shaking: most common hazard, causing damage to buildings and infrastructure
Landslides: triggered by earthquakes, can cause further damage and loss of life
Tsunamis: large ocean waves triggered by earthquakes, can cause widespread damage and loss of life
Liquefaction: process where soil or sediment becomes fluid-like during an earthquake, can cause damage to structures and infrastructure

An earthquake is a sudden release of energy in the Earth's crust, causing seismic waves to propagate through the Earth or along its surface.
Earthquakes can be caused by movement along faults, volcanic activity, or human activities such as injection of fluids into the ground.

Tectonic earthquakes result from movement along faults, plate boundaries, and plate tectonics.
Volcanic earthquakes are caused by movement of magma and gas beneath a volcano.
Collapse earthquakes result from collapse of underground caverns or voids.
Human-induced earthquakes are caused by human activities such as injection of fluids, mining, and construction.

Magnitude is a measure of the size of an earthquake, usually measured on the moment magnitude scale (Mw).
Intensity is a measure of the effects of an earthquake at a particular location, usually measured on the Modified Mercalli Intensity Scale (MMI).
Depth is the distance from the Earth's surface to the earthquake's epicenter.
Epicenter is the point on the Earth's surface directly above the earthquake's hypocenter (focus).
Hypocenter is the location of the earthquake's focus, where the seismic waves originate.

P-waves are primary waves, compressional waves that travel through the Earth's crust and mantle.
S-waves are shear waves, waves that travel through the Earth's crust and mantle, but not through the core.
Surface waves are waves that travel along the Earth's surface, causing the most damage.

Seismometers are instruments that detect and record seismic waves.
Seismographs are records of seismic waves, used to determine earthquake characteristics.
GPS (Global Positioning System) is used to measure ground deformation and movement.

Ground shaking is the most common hazard, causing damage to buildings and infrastructure.
Landslides are triggered by earthquakes, can cause further damage and loss of life.
Tsunamis are large ocean waves triggered by earthquakes, can cause widespread damage and loss of life.
Liquefaction is a process where soil or sediment becomes fluid-like during an earthquake, can cause damage to structures and infrastructure.