3.1 & 3.2 Study Guide Waves, Layers, & Continental Drift SG
The hottest layers are closest to the core.
describes the relationship between Earth's layers?
P-waves
the first waves to reach a seismograph after an earthquake are ____
focus
the initial point in Earth's interior where the energy of an earthquake occurs is the ____
epicenter
the position on Earth's surface directly above the earthquake source is called the ____
s-waves
wave that is stopped or absorbed by the outer core
continental drift
A hypothesis was introduced that proposed a single large landmass broke into smaller landmasses and formed the continents, which drifted to their present locations. What is the name of this hypothesis?
enter the core and are refracted
Acording to the figure, when p-waves encounter the boundary between the mantle and the core, the p-waves most likely:
shadow zones
As a result of seismic waves interacting with the liquid outer core, within what region do seismographs show no record of the earthquake ever having occurred?
tropical plant fossils discovered in Antarctica
Climate evidence that supports continental drift would have been:
seafloor spreading
Continental drift occurs because of ____
gravity
Earth formed in a swirling disk of matter surrounding the sun. As particles in the disk collided and stuck together, they grew larger and some eventually became planets. What force was responsible for the collisions between these particles?
They study the behavior of seismic waves.
How do scientists study the boundary between the crust and the mantle?
All seismic waves refract, changing speed and direction as they travel into new layers of the Earth.
How do seismic waves change when they travel into new layers of the earth?
mantle
Layer responsible for the convection currents that cause the tectonic plates to move.
Surface
Of the 3 seismic waves, the __?__-Waves are the slowest.
currents in the mantle rotate, pulling the crust along with it.
Seafloor spreading occurs because ____
the refraction of P waves through Earth's layers, and S-waves being absorbed by outer core
Seismic stations located within the shadow zone show no seismic activity of P & S waves. This is caused by:
magnetic reversals
Studying the ocean floor, scientists found rocks showing ___
convection currents.
Tectonic plates are moved due to ________________in the upper mantle.
Alfred Wegener
The Continental Drift theory was proposed by ____
magnetic field
The alignment of iron-bearing minerals in rocks when they formed reflects the fact that Earth's ____ has reversed itself several times in its past.
Crust
The least dense layer is the __?__
mountain ranges and fossils
The presence of the same ____ on several continents supports the idea of continental drift.
Planetary Differentiation
The process by which the Earth divided up into layers with different densities is called:
Harry Hess
The seafloor spreading theory was proposed by ____
Pangaea
The supercontinent in the continental drift hypothesis was called ____.
ridges
The youngest rocks in the ocean floor are located at the mid-ocean ____
mid-ocean ridges
There are long mountain belts that divide the sea floor and generate new sea floor as magma rises and erupts onto Earth's surface. What are these mountain belts known as?
Asthenosphere
Which layer of Earth does a tectonic plate ride on top of?
The inner core is solid because of the intense pressure and temperatures
Which layer of the earth is a solid and why?
radioactive decay
Which of the following is a source of heat in Earth's interior?
P waves are fastest and get there first
Which set of waves are probably the primary waves?
continents seem to fit together
evidence for Wegener's theory of continental drift
slow down
primary (P) waves ____ when they hit the liquid outer core
changes in seismic waves
scientists discovered changes in Earth's interior by studying ____
stop
secondary (S) waves ____ when they hit the liquid outer core
The crust is less dense than the mantle.
statement that best describes the difference between the crust and the mantle?