Flashcards in Tectonic Hazards Deck (33):
A zone of molten silicates and other minerals
Examples of tectonic plates
Eurasian, Oceanic, North American
The Two types of Crust
Oceanic- dense, thinner, newer
Continental- less dense, thicker, older
Heat currents in the molten magma that move the crust above very slowly
Slightly less pressure
Made of Iron and nickel which is solid despite temperatures of 3700 degrees because of intense pressure there
What is a Conservative plate boundary
A plate margin where two tectonic plates slide past each other
What is a constructive plate boundary?
Tectonic plate margin where rising magma adds new material plate that are diverging or moving apart
What is a destructive plate boundary?
Tectonic plate margin where two plates are converging or coming together and oceanic plate is subducted.
What are destructive plates associated with?
Violent earthquakes and explosive volcanoes
What is an example of a constructive plate margin?
In the Mid Atlantic Ridge where the Eurasian plate is moving away from the North American plate
What is a Subduction zone?
Where the heavier (denser) Oceanic plate is pushed beneath the less dense Eurasian plate.
Features found in a Subduction zone
Fold Mountains, Volcanoes, trenches, earthquakes
What is an example of a destructive plate margin?
Along the West coast of the America and Japan where the Philippines sea plate is pushed under the Eurasian plate.
What occurs at a conservative plate margin?
Earthquakes due to a release of stress energy which releases shock waves.
What is an example of a conservative plate margin?
The San Andreas Fault in California where the Pacific plate is moving north west faster than the North American plate
What do destructive plate margins create?
Earthquakes and volcanoes
What do constructive plate margins create?
What do conservative plate margins create?
What are volcanoes created by?
The intrusion of magma into the earth's crust and by the eruption of that magma onto the earth's surface through a vent
What are active volcanoes?
The constantly erupting volcanoes are active
Give an example of an active volcano
Stromboli on an island near Italy
What are intermittent volcanoes?
They erupt at fairly regular time periods
An example of an intermittent volcano
Mount Etna in Italy
What are in-active volcanoes?
Volcanoes that haven't erupted since the beginning of recorded history meaning they are extinct
What do shied volcanoes extrude?
Huge quantities of basaltic lava that gradually build a wide mountain with a shield-like profile
Example of a shield volcano
Mauna Loa is the biggest shield volcano on earth and rises over 9000m from the ocean floor and forms part of Hawii
What are composite or strato volcanoes?
Tall, steep sided conical mountains composed of lava flows and other materials in layers, these layers (strato) give rise to the name.
An example of composite volcanoes
Mt. Fuji in Japan where the lava is thick and sticky
What are volcanoes made up of?
Several layers of dust, ash, blast material and lava
What is a vent?
An opening through which magma escapes
What are earthquakes?
Vibrations in the earth's crust that creates shaking at the surface