Hazardous Earth Tectonics Flashcards
What is the Inner Core made out of?
Solid iron and nickel 5,000°C
What is the Outer Core made out of?
Liquid iron and nickel 4,000°C-5,000°C
What is the Lower Mantle made out of?
Solid peridotite 1,600°C-4,000°C
What is the asthenosphere made out of?
partially molten peridotite 900°C-1,600°C
What is the lithosphere - continental crust made out of?
solid granite 0°C-900°C (less dense)
What is the lithosphere - oceanic crust made out of?
solid basalt 0°C-900°C (more dense)
How does the convection affect the Plate Motion?
heat rises from the core and creates convection currents in the mantle and outer core - this movement causes the tectonic plates to move as they float on top of the mantle
What is the transform plate boundary?
2 tectonic plates slide past each other creating a shallow earthquake - San Andreas Fault in Haiti
What is the convergent plate boundary?
plates push together due to the convection currents, oceanic plate is subducted beneath the less dense continental plate - Pacific plate subducts beneath the Eurasian plate
What is the divergent plate boundary?
plates pull apart due to convection currents allowing material to rise, often takes the form of basalt - Iceland
What is a hotspot?
mantle plumes away from plate boundaries are columns of heat which expose weaknesses in the crust creating volcanoes - Hawaii
What is a composite volcano?
steap sides formed by layers of ash and lava, eruptions may be pyroclastic flow rather than lava, when they erupt they are explosive and pose a threat to nearby life and property
What is pyroclastic flow?
superheated mixture of hot steam, ash, rock and dust
What is a shield volcano?
low with gently sloping sides formed from layers of lava, eruptions are typically non-explosive, produce fast flowing lava that can flow for many miles, eruptions tend to be frequent but relatively gentle and less destructive
How big was the Haiti 2020 earthquake?
magnitude: 7.0
shallow focus: 13km on conservative plate boundary