Tectonics EQ1 (1.1) Flashcards
what is a convergent plate boundary ?
where the plates are moving towards each other and one crust is forced down underneath the other plate. This can form volcanoes , deep ocean ridges and fold mountains.
what is a divergent plate boundary ?
where the plates are moving away form each other which forms a new crust. This can form mid Atlantic ridges at sea and rift valleys on land.
what is a conservative plate boundary ?
where the two plates slide past each other and crust is neither created nor destroyed.
what is a collision boundary ?
where two plates meet and they are both the same density causing both to push up creating high fold mountains.
what causes the plates to move ?
Radioactive decay of isotopes generate heat radiating outwards from the inner core. This causes convection currents which move the plates by convectional drag.
what theory did Wegener come up with ?
continental drift which is the theory that all the continents where once one big land mass called pangea.The discovery of sea floor spreading and fossils of the sane species found in different continents helped solidify his theory.
what is the difference between interplate and intraplate ?
interplate happens on a plate boundary
intraplate happens on interior of a plate
what is a hotspot ?
an area in the middle of a plate with a lot of volcanoes created by plumes of magma under the plate
what are the 3 types of lava ?
- basaltic-hottest type and formed by melting of the mantle minerals. gentle eruptions
- andesitic-formed by oceanic plates plates melting and mixing with seawater. erupts violently
- rhyolitic-coolest lava and is formed by the melting lithosphere mantle. located in super volcanoes
what are the 2 types of volcanoes ?
composite volcanoes -steep sided -andesitic lava - violent eruptions shield volcanoes -basaltic lava -not as violent eruptions -frequent eruptions
what are the 3 things in the progression of vulnerability in a natural hazard ?
root causes, dynamic pressure and unsafe conditions
what are the 4 types of shock waves ?
- primary(P) waves- push through crust
- secondary(S) waves- slower then p waves only move up and down
- rayleigh waves- move through surface crust in a rolling motion
- love waves- fastest wave that move through crust and moves side to side
how are tsunamis created ?
by undersea earthquakes, volcanic eruptions or landslides that cause water column displacement.
what is liquefaction ?
when loosely packed grains of soil have spaces filled with water and during an earthquake the shaking increases the space between the grains meaning the water comes up
What is a Beniof zone ?
The area of seismicity corresponding with a plate being thrust down in a subduction zone. This generates magma which can erupt with explosive force.
