Evidence of Plate Motions
Wegener developed the hypothesis that Earth’s land masses had once been fused together, and then slowly broke apart in a process called:
Continental Drift
What explains how Mount Everest formed?
The mountain formed when two tectonic plates collide at a convergent boundary
The type of stress that pulls on and thins an area of Earth’s crust is called:
Tension
Volcanoes may emerge at long cracks in Earth’s crust at _____________ ridges, on continents near convergent _____________, and at random locations away from plate boundaries called ________________.
Mid-ocean
Boundaries
Hot spots
Also called a stratovolcano, it is made of alternating layers of lave flows and ash falls.
Composite Volcano
Evidence that supported the hypothesis of continental drift included fossils, land features and:
Climate Data
The circular movement of material in the mantle that drive plate movement is called:
Convection
When a plate is compressed, it can create anticlines and synclines that can become:
Mountains and Valleys
What causes volcanoes to form along a mid-ocean ridge?
A mid-ocean ridge forms long, underwater mountain ranges. Some have a rift valley down the center, and lave can pour out of cracks in the rift.
The zipper-like mountain ranges that run across the ocean are called:
Mid-ocean Ridges
Plates move apart from each other at a:
Divergent Boundary
How much more energy is released by an earthquake with a magnitude of 8.0 on the moment magnitude scale than one with a 6.0 magnitude:
64 more times
Why are volcanoes often found along both convergent and divergent plate boundaries?
Both types of boundaries result in molten rock coming to the surface, which can form a volcano. At convergent boundaries, the subduction of one plate under another can cause molten rock to come to the surface. At divergent boundaries, magma comes to the surface from the mantle as plates move apart.
A single number that geologists use to assign to an earthquake based on the earthquake's size.
Magnitude
Explain one of the types of stress that affect Earth's crust:
Need to explain one of the three: Tension - pulls on Earth's crust, stretching the rock to make it thinner, Compression - squeezes rock until it bends or breaks. When compression occurs at a large scale, rock can be folded into mountains or Shearing - occurs when rock is being pushed in two opposite directions, to the point that it bends or breaks.
Earthquakes often occur along __________________ as a result of the buildup of stress.
Plate Boundaries
Describe the roll that stress plays in the production of earthquakes and tsunamis.
At convergent or transform plate boundaries, stress builds up between plate edges made of rock. When a breaking point is reached, the stress is relieved and the built-up energy is released in the form of an earthquake. If the earthquake results in a displacement of water, a tsunami can form
Runny lave oozes from the vent of a broad, gently-sloping shield volcano. What type of eruption is this?
Quiet
A break in the rock of Earth's crust or mantle
Fault
How did the discovery of mid-ocean ridges support the hypothesis of continental drift?
It provided an explanation of how Earth continually generates its crust.
A local official pledges to have a new highway built over a transform boundary. Explain why this may be a bad idea.
Plates move in opposite directions at transform boundaries. Any structure that is built on or near such a boundary could be cut in half, offset, or otherwise damaged when the plates move.
Describe how ocean floor uplift and landslides can cause tsunamis:
Ocean floor uplift occurs when an area of Earth's crust moves upward during an earthquake. When a landslide occurs, a huge mass of rock and dirt comes away from a mountain. If that occurs near the ocean, the rock can go into the ocean. Both of these events can displace a huge amount of water, which may cause the huge waves of a tsunami to form.
You are sailing in the South Pacific Ocean, far from any plate boundary. Looming on the horizon is a dark, broad, rounded island with sparse vegetation. A few thin flows o orange lave drip into the sea. Some smoky vapor unfurls from the center of the island. What kind of volcano is this? Explain.
Most likely it's a shield volcano (or hot spot volcano), based on the shape, size, and slow eruption, and its distance from any plate boundary.
The sinking movement of ocean floor back into the mantle
Subduction