SCIENCE: LESSON 3 THE DYNAMIC EARTH Flashcards
Is a mountain that opens downward to a reservoir of molten rock called magma bellow the surface of Earth. It is controlled by the geological processes that formed them and act on them even after they have formed.
Volcano
How many are volcanoes on Earth which have the potential to become active as they have already erupted within the past 10,000 years.
1,500 volcanoes
About how many percent _% of the world’s volcanoes are located near the boundaries of tectonic plates, while the remaining _% are thought to be associated with mantle plumes and hot spots.
95% and 5%
Hotspots and mantle plumes were first observed in what year?
1960’s
Who is the Canadian geophysicist and one of the founders of the plate tectonics. And he also found an interesting pattern- the island became progressively younger to the southeast.
John Tuzo Wilson
What does John Tuzo Wilson state in his theory? This theory also gave support to Plate Tectonics Theory.
His theory states that volcanic chains, like Hawaiian Islands, result from the slow movement of a tectonic plate across a fixed hotspot.
Who’s the American geophysicist that developed Wilson’s theory in 1971?
William Jason Morgan
What does William Jason Morgan propose?
Morgan explained hotspots when he proposed for the existence of roughly cylindrical convective upwelling in Earth’s mantle.
It is the areas or columns where heat or rocks in the mantle rise toward Earth’s surface. They are thought to spread out laterally at the base of a continent that allowed an increase in pressure that stretches the crust resulting in uplift, fracture, or rift.
Mantle plumes
_ are locations on Earth’s surface that have experienced active volcanic activities for a long period of time.
Hotspots
Total number of most active hotspots in the world?
40 to 50
Examples of active hotspots at present
Galapagos, Hawaii, Iceland, Reunion and Yellowstone
It occurs when matter such as magma circulates within the Earth. It is caused by the change in temperature, density and pull of gravity.
Convection
It is a natural phenomenon that is characterized by a sudden, violent shifting of massive plates underneath the Earth’s surface.
Earthquakes
The point within Earth along the geological faults where the earthquake originates is called the?
Hypocenter (focus)
