all of tectonics Flashcards
What is response?
what happens after an event: evacuation, immediate assistance and asses damage (by charity, services and insurers)
Where do most earthquakes and volcanoes occur?
near plate boundaries
What is a divergent plate boundary?
cause effusive basaltic eruptions and rare shallow earthquakes
What is an example of a divergent plate boundary?
mid-atlantic ridge - Iceland
What is a convergent plate boundary?
cause violent andesitic eruptions and shallow, deep powerful earthquakes, volcanic cones, ocean trenches and mountains
What is an example of a convergent plate boundary?
Japan - Pacific plate moving NW under Okhotsk plate
What is a conservative plate boundary?
Cause powerful shallow earthquakes and diverted rivers along faults
What is an example of a conservative plate boundary?
San Andreas fault
What are infra-plate earthquakes?
Caused by solid crust cracking over millions of years and primary collision at a plate boundary
What are infra-plate volcanoes?
Caused by hot spots from molten upwelling or from mantle plume under crust
What are convection currents?
Caused by heat radiating outwards from core that occur due to mantle behaving like a viscous liquid
What is slab pull?
When denser oceanic plates are subducted at cold downwellings by gravity
What is ridge push?
When magma rises at constructive margin and pushes the plates apart
What is paleomagnetism?
Movement of plates apart identified by magnetic pattern caused by magnetic field reverse (every 4 million years). Mid-oceanic ridge contains iron that lines itself parallel to magnetic field and ‘sets’ after it cools, permanently marking magnetic field
What is the activity at divergent boundaries?
shallow, low magnitude earthquakes and effusive basaltic eruptions
What is created at divergent boundaries?
Rift valley, volcanic isle and transform faults
What is the activity at convergent boundaries?
shallow to 700km, high magnitude earthquakes (ocean-ocean plates)/ moderate magnitude (ocean-continent), explosive eruptions
What is created at convergent boundaries?
ocean trench, fold mountains (ocean-cont’) or volcanic isle and ocean trench (ocean-ocean)
What is the activity at transform/conservative boundaries?
shallow, moderate magnitude earthquakes with usually no volcanic activity
What is created at transform/conservative boundaries?
ridges and scars on the surface
What is the activity at collision boundaries?
shallow to middle, moderate magnitude earthquakes with usually no volcanic activity
What is created at collision boundaries?
plateaus and fold mountains (Himalayas)