Types of forces
This force pulls objects toward the center of the Earth and gives them weight.
What is gravity?
These cracks in the Earth’s crust are where most earthquakes occur.
What are fault lines?
Newton’s law that states “An object will remain at rest or in motion unless acted upon by an external force.”
What is Newton’s First Law?
Flexible supports placed between a building and its foundation to absorb seismic energy.
What are base isolators?
Earthquakes caused by the movement of tectonic plates.
What are tectonic earthquakes?
This force resists motion between two surfaces that are touching. It slows down moving objects like rolling rocks.
What is friction?
the outermost layer of the Earth, where most earthquakes and human activity occur.
What is the crust?
The equation F=ma comes from this law.
What is Newton’s Second Law?
This building material is flexible and absorbs vibrations well, making it useful in earthquake-resistant homes.
What is wood?
This is the force that pushes back equally when one object exerts a force on another, as stated in Newton’s Third Law.
What is the reaction force?
These waves carry energy away from the earthquake’s focus and cause the shaking we feel.
What are seismic waves?
This law states that for every action, there is an equal and opposite reaction.
What is Newton’s Third Law?
These strong but brittle materials can crack or crumble under intense pressure.
What are brick and concrete?
These earthquakes happen when caves or underground mines collapse.
What are collapse earthquakes?
When an object stays still because all the forces acting on it are equal and opposite, it is said to be what forces.
What is Balanced Forces
The instrument scientists use to record and measure earthquake strength and duration.
What is a seismograph?
The force that resists motion between two surfaces in contact.
What is friction?
These strong and slightly flexible materials are often used to reinforce structures.
What are steel and metal?
These earthquakes happen when magma moves beneath the Earth's surface, causing pressure and fracturing rock layers even before an eruption occurs.
What are volcanic earthquakes?
During an earthquake, this type of force acts on buildings as the ground shakes, trying to move structures back and forth.
What is seismic (or shear) force?
The point beneath Earth’s surface where an earthquake begins.
What is the focus (or hypocenter)?
When all forces acting on an object are equal and opposite, the object is said to be in this state.
What is equilibrium?
In construction plans, these must be labeled to show how energy and weight are distributed through a structure.
What are forces, support beams, and connection points?
This type of earthquake is triggered by human activity—such as mining, dam construction, or hydraulic fracturing—rather than natural tectonic movement.
What is an induced earthquake?