Earthquakes Flashcards
the vibration of the Earth produced by the rapid release of energy
Earthquake
energy released from here radiates in all directions
Focus
location of the focus projected on the Earth’s surface, energy released in the form of waves
Epicenter
Rocks on both sides of an existing fault are
deformed by tectonic forces; Rocks bend, thus store elastic energy; Frictional resistance holding the rocks together is overcome when enough energy is stored; Energy breaks the rock, rupture propagates and
sends EQ waves into surrounding rock
Elastic Rebound Theory
instruments that records seismic waves
Seismographs
Body, P-waves, S-waves, surface waves
Types of Waves
move through the interior of the Earth
Body waves
primary waves; compressional waves that travel quickly
through rock.
P-waves
secondary waves; shear waves
S-waves
move across the surface of the Earth; complex motions; cause greatest destruction
Surface waves
Charles Richter, 1935; Accounts for the decrease in wave amplitude with increased distance; Based on the amplitude of the largest seismic wave recorded in Southern California
Richter Scale
estimates the amount of energy INreleased at the source of the earthquake
Magnitude
a measure of the degree of earthquake shaking at a given locale based on the amount of damage
Intensity
The intensity of ground shaking in a given area from a given earthquake is dependent
on three things.
(1) the energy released during the earthquake
(2) the distance from the site to the hypocenter of the earthquake
(3) the type of bedrock (the ground or substrate) in the place where the shaking is felt.
Intensity(and Magnitude)
95% of earthquakes occur on a plate boundary
Plate Boundaries
