Earthquakes Flashcards
Earthquakes:
are the vibrations in the ground that result from the movement along breaks in Earth’s lithosphere.
Fault:
is a fracture in the lithosphere where one block of rock moves toward, away from, or past another.
Stress:
the force exerted when an object person on, against, or pulls away from another object
Seismic Waves:
the energy waves that travel as the vibrations caused by earthquakes
Focus
the point underground where rocks first begin to move.
Epicenter
the point on Earth surface directly above the focus
Primary Waves:
fastest wave, first to reach any location after earthquake. Particles of material are pushed together and pulled apart.
Secondary Wave
travel half as fast, second wave to reach a location. Particles are shaken up, down, side to side, These waves can not travel through liquids
Surface Waves
Travel the slowest, Cause greatest ground movement and damage
Seismograph
a device that constantly records movement of the ground.
Magnitude
amount of energy released by an earthquake
What seismic wave causes the most damage?
Surface
In triangulation, seismologists use ___ seismometers
3
Strike Slip Fault:
Transform boundary, two blocks of rocks slide past each other
Reverse Fault:
Convergent boundary, rocks go upward
Normal Fault:
Divergent boundary, rocks go down
Most earthquakes occur:
Along plate boundaries
The total energy released by an earthquake is best measured by the ___ scale:
Modified Mercalli scale
What have scientists learned more about by studying earthquakes?
Composition and structure of Earth’s interior
The magnitude of an Earthquake is measured by the __ scale
Richter Scale
Primary waves __ when they hit the liquid outer core
Slow down
Secondary waves __ when they hit the liquid outer core
Stop
Earthquake risk is based on land’s:
History
The damage done by an earthquake is measured by the ___ scale
Modified Mercalli
