Plate Tectonics, Earthquakes, and Mountains Flashcards
Evidence of support of the continental drift hypothesis
The fit of the continents, paleoclimatic evidence, fossil evidence, rock type, and structural similarities
How old is Pangea?
Around 200 million years old.
When did Alfred Wegener propose his hypothesis?
He proposed it in 1915
Earthquake
Vibrations of the earth produced by a sudden release of energy
Fault
A fracture or zone of fractures in rock along which the two sides have been displaced relative to each other.
Focus
The point within the earth along the fault from which earthquake waves originate
Epicenter
The point on the earth’s surface directly above the focus
What is the Elastic Rebound Hypothesis?
When rocks bend until the strength of the rock is exceeded, then rupture occurs, after that they quickly rebound to an undeformed shape, and the they release energy in waves that radiate outward from the fault
What is seismology?
The study of earthquakes waves
Body waves
waves that travel in all directions from the focus through the body of the earth, there are two types.
Primary waves (p-waves)
a push-pull motion (compression), travel through liquid, solid, and gas. Fastest waves.
Secondary waves (s-waves)
Shake motion, travel only through solids, slower than p-waves
Surface waves (L and R waves)
complex motion, slowest out of all the waves, the waves we feel during earthquakes.
What is a seismograph?
An instrument that records the data collected from the seismic waves of the earthquake.
What is a seismogram?
A written record by the seismograph
How do you locate an epicenter of a earthquake?
Use the Triangulation Method, which is a mathematical method for locating the epicenter of the earthquake using three or more data sets from seismic station.
What are the steps of the Triangulation Method?
First mark the locations of the first p-wave and s-wave, then find the distance (lag-time) between the first p-wave and s-wave to tell you how many minutes the waves are apart, then record the time of the first p-wave and s-wave, finding the difference between the two times, then do that for two other seismic stations. Then find the distance from the seismic stations.
What are some factors that determine destruction?
Some factors are magnitude of an earthquake and the proximity to population.
What are some destruction forms?
The ground shaking, tsunamis, landslides, fires, and liquefaction.
Sheeting
caused by curved joints in large igneous bodies like batholiths
Columnar joints
produced in igneous rocks caused by shrinking as magma cools
Joints
fractures where no displacement occurs
Strike-slip faults
fault planes are nearly vertical, the movement is horizontal (shear)
Thrust faults
low angle reverse fault, and they produce the largest mountains. (compressional)
