Plate Tectonics Flashcards
The Earth’s lithosphere consists of what layers?
The crust; the upper part of the mantle (rigid mantle).
What are the three (3) various kinds of rocks consisting the crust?
Sedimentary; metamorphic; igneous
What is the average density of the crust? What is the thickness of the crust?
2.8 g/cm^3
5 to 5 km
The crust is thickest in _____ and thinnest along the _____
Mountains; ocean floor
There are two (2) kinds of crust: the thicker but less dense _____; and the thinner but denser _____.
Continental crust; Oceanic crust
According to the plate tectonics model, the entire lithosphere of the Earth is broken into numerous segments called what?
Plates
Geologists consider seven (7) large plates, these are?
North American Plate; South American Plate; Eurasian Plate; African Plate; Indo-Australian Plate; Pacific Plate; and Antarctic Plate.
The movement of plates are described to be slow but constant. Such movement is called? The theory of moving lithospheric plates?
Tectonics. Plate tectonics.
An earthquake releases three (3) types of seismic waves. These are?
Primary (P-waves); Secondary (S-waves); Long surface waves (L-waves)
Among the three (3) seismic waves, which two travel into the Earth’s interior? Which one travels on the surface?
Primary (P-waves) and Secondary (S-waves) travel into the Earth’s interior. Long surface waves (L-waves) travel on the Earth’s surface.
How is the distance of the recording instrument to the earthquake’s focus related to the difference in the arrival times of the first P-wave and the first S-wave?
The farther the distance, the greater the difference in arrival times.
What does the difference in the arrival times tell us and does not tell us?
It estimates the distance of the earthquake’s focus from the seismic recording station. It, however, doesn’t tell us the direction.
This method allows us to determine where the epicenter of the earthquake is located through drawing circles around seismic stations whose radii are scaled to the distance of the station from the earthquake. What method is this? How many seismic recording stations are required?
Triangulation Method. Three (3) seismic recording stations.
Geologic events and deformations—such as earthquakes and formation of mountains, volcanoes and trenches—occur in plate boundaries. These are classified into three (3) distinct types according to the type of movement they exhibit. What are these three (3) types?
Divergent plate boundary; Convergent plate boundary; Transform fault boundary.
This type of plate boundary is exhibited by how plates move apart each other—creating a zone of tension.
Divergent plate boundary.
This type of plate boundary is exhibited by the sliding or grinding of plates past each other. What is this? What fault bounded by the North American and Pacific plates best exemplifies this?
Transform fault boundary. San Andreas fault.
In a convergent plate boundary situation, which one sinks, the continental or the oceanic crust? Why?
The oceanic crust. Owing to it being more dense/denser than the continental crust.
Collision of two plates—an oceanic and a continental—gives rise to the formation of what geological occurrence near the edge of a continental leading plate?
Volcanic arc(s).
This process is described as the bending of the crust towards the mantle.
Subduction process.
As the denser crust sinks toward the mantle, the sunk crust melts—owing to the mantle being hotter—which forms what substance which rises to the crust and causes volcanic activities after addition of volatile material such as water?
Magma.
With a oceanic-continental convergence situation, this important geological feature occurs or is formed? They are the deepest part of the ocean.
Trench, also known as submarine valleys.
Aside other geological features occurring or forming owing to oceanic-continental convergence, this is also a subsequent effect of the continuous grinding of plates against each other which releases huge amounts of energy. What is it?
Earthquakes.
Such geological occurrence which releases energy after continuous plate grinding is classified according to its foci’ varying depths. What are these, according to the depth: 60km deep - _____; 60km to 300km deep - _____; and 300km to 700km deep - _____.
Shallow earthquakes; intermediate earthquakes; deep earthquakes
It is a Japanese term for “harbor wave;” it is a series of ocean waves with very long wavelengths—typically hundreds of kilometers—caused by large-scale disturbances of the ocean or underwater earthquakes.
Tsunami.
