Earthquakes
What causes an earthquake?
Earthquakes are caused when two tectonic plates bump into each other.
Where is the Mid-Atlantic Ridge located?
Down the center of the Atlantic Ocean.
What did Alfred Wegener first notice which made him think of the idea of continental drift?
Wegener noticed that the shape of the continents would fit together like puzzle pieces. This led him to think that the continents must have all been together and touching at one time.
Where are most volcanoes located?
Near the edge of a tectonic plate
What happens when two pieces of continental crust collide?
Where are most earthquakes on Earth located?
Most earthquakes are located around the edge of the Pacific Plate, also known as "The Ring of Fire."
They also occur at the edges of other tectonic plates.
How is new oceanic crust created?
The seafloor spreads apart at the edge of the tectonic plate and magma bubbles up into the crack, creating new crustal rock.
How does fossil evidence support the idea of Plate Tectonics?
Fossils of the same species have been found on continents which are very far apart. The organisms could not have arrived by swimming, wind, or drifting. This means that at one time, the two continents must have been touching and have since moved.
Where are most volcanoes located?
At the edges of Tectonic Plates
Where does the energy come from to make an earthquake happen?
Earthquakes are the result of moving tectonic plates. The plates move because of convection currents, which are powered by heat from the core.
Describe how earthquakes are related to uplift of a mountain.
When tectonic plates squeeze together, one jolts over the other and moves higher. Over millions of earthquakes and millions of years, these tiny movements create a huge mountain.
What causes seafloor spreading?
Convection currents in the mantle push upward on plates and make them move apart at the "cracks."
How do mountain ranges on different continents support the theory of plate tectonics?
When analyzing mountain ranges on different continents, geologists noticed that they had the same types of rock in the same layering pattern. This could only have happened if the mountains formed on the same land mass, then separated over time.
How are volcanoes related to tectonic plates?
Near the edges of continents, the continental plate is moving over the oceanic plate. When the oceanic plate is pushed down, it melts, the magma travels upward, and a volcano forms.
Describe the energy source and motion that makes Earth's plates move on the mantle.
Radioactive decay in the inner core sends heat outward to the mantle. Inside the mantle, melted rock is heated, expands, then rises upward toward the crust. When this rock hits the crust, it moves sideways, dragging the plate along and cooling down. After it cools, it becomes more dense and sinks back down toward the core.