Earthquakes Flashcards
What is a P wave?
Primary. A compressional, push-pull wave, that travels through solids, liquids and gases. Has the greatest velocity of all waves. ~4.8km/sec. Like a slinky
Aftershock
An earthquake that occurs as a consequence of a previous earthquake of larger magnitude.
What is a S wave?
secondary wave that arrives after the P wave. (side to side motion?)
Earthquake
The violent motion of the ground that occurs when rocks being stressed suddenly break along a new or preexisting vault
Elastic bound theory
Theory of fault movement and earthquake generation holding that faults remain locked while staring energy accumulates in the rock formations on both sides temporarily deforming them until a sudden slip along the fault releases the energy.
Epicenter
The geographic point on the earths surface directly above the focus of an earthquake
Fault mechanisms
The type of fault rupture (normal, thrust, or strike-slip) that produced an earthquake; it is determined by the orientation of the fault rupture and the direction of slip
Fault slip
The distance of the displacement between two blocks that occurs during an earthquake when elastic rebound causes the blocks on either side to spring back to their undeformed state
Focus
The point along a fault at which slip initiates an earthquake
Foreshocks
A small earthquake that occurs in the vicinity of but before the main shock
Intensity scale
A scale for estimating the intensity of an earthquakes shaking directly from an events destructive effects
Magnitude scale
Richter.
For estimating the size of an earthquake using the logarithm of the largest ground motion registered by a seismograph
Or the logarithm of the area of the fault rupture (moment magnitude)
Recurrence interval
The average time interval between the occurrence of two raptrues on the same fault that produce earthquakes of approximately equal magnitude.
Seismic hazard
The intensity of shaking and ground disruption in an earthquake that can be expected over the long term at some specified locaiton, expressed in the form of a seismic hazard map.
Seismic risk
The earthquake damage that can be expected over the long term for a specified region, such as a country ro state, usually measured in terms of average dollar loss per year.
