Exam 2 Flashcards
Oceanic crust is composed mainly of
Basalt
Which of the following concepts was developed earliest?
Continental drift
The - includes Earth’s crust and the uppermost strong and rigid part of the mantle.
Lithosphere
The Mid Oceanic Ridge is elevated above the surrounding sea floor because
It is made of the newest, hottest, lowest density lithosphere
Tectonic plates typically move at rates of
1-16 cm per year
Where two lithosphere plates of different densities converge, the denser one sinks into the mantle beneath the other in a process called -.
Subduction
At a transform boundary
Two plates slide horizontally past each other
Which of the following is a divergent plate boundary?
The Mid Atlantic Ridge
The mantle lithosphere system circulates in great - cells.
Convection
The Hawaiian islands are
Generated by a hot spot
A rock that has deformed - under stress keeps its new shape
Plastically
According to the theory of isostasy
The lithosphere is in floating equilibrium on the asthenosphere
P and S wave
Travel through the Geosphere as body waves
The geographic location of an earthquake on Earths surface is the -.
Epicenter
S (shear) waves
Move only through solids
Ground vibrations are measured by
Seismograph
The - scale measures the total amount of energy released during an earthquake, based on the amount of movement and the fault surface area
Moment magnitude
Which of the following statements about earthquakes is true?
Earthquakes occur at all types of plate boundaries
To measure the distance from a recording station to an epicenter
Compare the time interval between the arrival of P and S waves with a time-travel curve
The San Andreas fault zone is an example of
Earthquake zone at a transform plate boundary
Geologists learned that the outer core is liquid because - do not travel through the outer core.
S waves
Where is the Earths magnetic field generated
Outer core
Which causes generation of magma?
Decreasing pressure
The volcanoes along the subduction zones encircling the Pacific Ocean basin are called the
Ring of Fire
Dated rocks and zircon crystals suggest that the earliest continents had formed by
About 4.2 billion years ago
Magma with a high silica content has a greater tendency to - in the crust, compared with magma with a lower silica content
Solidify
A stratovolcano
Forms by repeated lava flows and pyro clastic eruptions over a long time
A pluton with an outcrop area of more than 100 swayed km is called a
Batholiths
The most catastrophic volcano explosions occur when - reaches the earths surface
Granitic magma
A caldera is
A circular depression formed as the roof of a magma chamber collapses during an eruption
31 the addition of CO2 into the atmosphere by volcanic eruptions
Can lead to global warming
A cool rock near the Earths surface is more likely to - than a similar rock that is hot and under great pressure.
Deform plastically
A fold in a rock indicates that
The rock has deformed in a plastic manner
A sycline
Is the portion of a fold that arches downward
A reverse fault occurs as a result of
Crustal shortening
The term - refers to the process of mountain building
Orogeny
Where two oceanic plates converge, one sinks beneath the other and dives into the mantle forming
An island arc
A subduction complex
Is formed from slices of rock and sediment scraped off the ocean floor during subduction
The Andes mountains were formed by convergence of a plate carrying - crust at its margin with a plate carrying - crust.
Oceanic, continental
The Himalayas were formed
By convergence of the Indian plate and the Eurasian plate
