Earthquakes
Approximately how many earthquakes are strong enough to be felt each year worldwide
75
What is the weaker, hotter zone beneath the lithosphere that allows for motion of earth's rigid outer shell?
Asthenosphere
Underground igneous rock bodies are called
Lava flows
Which of the following is not a factor that determines if a volcano erupts explosively or quietly?
size of volcanic cone
At what type of plate boundary do plates move apart, resulting in the upwelling of material from the mantle to create new seafloor?
divergent
What scale do scientists today most often use to express the magnitude of an earthquake?
Moment magnitude scale
Alfred Wegener is best known for what hypothesis?
Continental Drift
Magma's viscosity is directly related to its
Temperature and chemical composition
Silica content
How does an increase in pressure affect a rock’s melting temperature?
Raises the melting point of rock beneath the surface
What property that is different for P and S waves provides a method for locating the epicenter of an earthquake?
speed
The point at which an earthquake begins is called a(n)
Focus
What is the name of the supercontinent, given by Wegener, that existed before all present day continents?
Pangaea
What is the large depression at the top of some volcanoes called?
Crater
Which type of volcano consists of layers of lava flows and pyroclastic material?
cinder cone
Movements that follow a major earthquake often generate smaller earthquakes called—
aftershocks
What material do scientists believe makes up a large part of the upper mantle
peridotite
Most deep focus earthquakes occur near
Mid ocean ridges
The greatest volume of volcanic activity is produced by:
Shield volcanoes
Which one of the following was not used as support of Wegener’s continental drift hypothesis?
Paleomagnetism
An earthquake in the ocean floor can cause a destructive sea wave called a—
tsunami
In order to find the epicenter of an earthquake, what are the minimum number of stations required
Three
One of the main objection's to Wegener's hypothesis of continental drift was that he was unable to provide an acceptable
mechanism of continental drift
What feature may arise in an intraplate area over a rising plume of hot mantle material?
Hot spot
At what type of plate boundary do plates move apart, resulting in the upwelling of material from the mantle to create new seafloor?
Divergent
The instrument that records earthquakes is called
seismograph