Earthquakes are sudden, violent shaking of the ground caused by the release of energy in the Earth’s crust. The energy released creates seismic waves that travel through the Earth and can be detected with instruments. Earthquakes can cause destruction in the form of buildings collapsing and landslides occurring.
Epicenter: the point on the Earth’s surface directly above the origin or focus of an earthquake Focus: where the earthquake originates Fault Line: a fracture or crack in the Earth’s crust ----Plate boundaries are always faults, but not all faults are plate boundaries. Richter Scale: a 1-10 scale to measure the size of an earthquake.
Some important vocabulary:
Earthquakes can cause the ground to liquify, when loose, wet soil acts like a liquid during shaking. Tsunamis are large waves caused by underwater earthquakes. Earthquakes can cause landslides, when an earthquake shakes the ground so much that the land can suddenly move downhill.
Did you know?
Brain break: Draw a dog that has sunglasses on. You have 20 seconds!!!!!
What is the primary cause of earthquakes?
- Volcanic eruptions
- Meteorite impacts
- Tectonic plate movement
Which scale is used to measure the magnitude of an earthquake?
- Saffir-Simpson Scale
- Beaufort Scale
- Richter Scale
What is the point on Earth's surface directly above where an earthquake originates called?
- Seismic Zone
- Quake Zone
Which type of boundary is associated with subduction?
- Divergent boundary
- Transform boundary
- Convergent boundary
Which country experiences more earthquakes than any other country in the world?
A seismograph is a device that measures and records earthquakes. It records the strength and direction of seismic waves as they pass through the Earth’s crust. Seismographs help scientists understand the causes and effects of earthquakes.
What is a Seismograph?
When an earthquake happens, it sends two waves outward from the focus. P Waves: fast-moving, smaller waves. They create a "small" rumble. Usually, only seismographs can detect them. S Waves: slow-moving, larger waves. These are the "big" waves that cause ground shaking and damage.
P Waves & S Waves Explained
Scientists can locate an earthquake's epicenter using the distance from seismographs. P Waves always travel at a certain speed. S Waves always travel at a certain speed. By measuring the time between P & S Waves reaching a seismograph, you can calculate how far away the epicenter is. You'll get to do this in a gizmo tomorrow!
Locating an Earthquake's Epicenter
If it's a long time between P & S waves from an earthquake, then the epicenter is...
- Far Away
- Right under you
Brain break: Draw a dog that has sunglasses on. You have more time now :)