tectonics Flashcards
what is a divergent plate boundary
what kind of earthquakes occur
a divergent plate boundary is where plates move apart which means that magma rises and cools forming new crust and forming a mid ocean ridge.
only mostly small shallow earthquakes
what is a convergent plate bondary
what dose it do to volcanoes and earthquakes in the area
plate boundary that push together deforms the collision area. material melts in the mantel
more earthquakes and the formation of active volcanoes
what is a conservative plate boundary?
what results as a result of movment
it is where the plates move along side each other
can resulting the formation of mountains swell as well as quite strong shallow focus earthquakes
give an example of a conservative boundaries
what generally causes earthquakes at these boundaries
San Andres fault
realses of friction
where are divergent boundaries
what is made as they move apart
they are generally oceanic crust under the ocean
what is the most dangerous plate boundary generally and why
convergent
as the plates approach each other one of them subject typically the denser and thinner crust which is the oceanic crust
- this causes friction which when realised causes very powerful earthquakes
what is comon above a subduction zone
- montaian belt
- magmatic activity
- active siesimity
what is a destructive boundary
convergent plate boundary
what forms when 2 continental plates meet
fold montains
what is created at a divergent plate bondaries
-rift volcanoes, generally less explosive and more effusive
what are hotspot volcanoes and how are they formed
they are found in the middle of the plate and are formed by magma plumes threw the plate
where is the majority of volcanic activity
plate boundaries
what is the most common type of natural disaster
what is the least common type of natural disaster
hydrlogical
Geophysical
what makes a natural event count as a disaster
what about a mega disisater
10 pepole dead
?
case study toku 2011
- cuase
-size
-deaths
-economic impact
-response
tohku earthquake 2011
-undersea earthquake at plate junctions measured 9.0 on the magnitude scale
-20,000 people killed 90% by drowning, 100,000 choldren sperated from there famiies 300,000 people in total displaced
-360 billion dollars in damage, 47,700 buildings destroyed, 230,000 vehicles destroyed, goverment debt increased due to an injection of billions of yen to restart the economy
-100,000 japanese self defence force members came to help as well as the red cross and US military personal sent to aid the rescue
-breach of sea wall lead to damaged nuclear power plant and a melt down in 3 reactors
what cuases tunamis
- earthquake(realsea of tention) can cause a subduction of plate or mega thrust of the plate = displacement of water and a wave motion created
- displacment of water through large movement of sediment of metorite in water
what is a disaster
+100 pepepole die in an event
what is a mega diaster
over 2000 deaths
what factors effect vulnerability of a country/ settlement
- location
-education
-investment in adaption measures
-planning for disasters and hazards
Haiti
name 3 ways in which a volcanic activity can be mitigated
-tilt meters can tell when a volcano is bulging and close to erupting
-boar holes tell how different the temperature is as magma rises
- building concrete shelters from volcanic ash and lava bombs
name 3 hazards of volcanic activity
- ash fall can be heavy on roofs which cuases them to collapse, distrups machinarie and flight paths and kills crops
-plyromcaltic flow- flow of tephra and poisonous gases moves down the side of the volcano at almost 700km/h
-lava flows down the side of the mountains and cools
-lahars mixture of water and volcanic material traveling down river valleys at 60km/h
-gas eruptions- water vapouoir and sulfur dioxide can be poisonous high high concentrations
cuase acid rain which cuases damage to buildings and plants and blocks sun energy
case study Indian ocean tsunami
- causes
case study Indian ocean tsunami
-It was caused by a rupture along the fault between the Burma plate mega thrust earthquake magnitude 8.8
- total economic cost 10bliion$
- 230,000 deaths in 14 countries
- world food programme provided food for 1.3 million
-14$ billion sent in foreign aid
-1.3 million ,made homeless
-51,000 boats destroyed
HATI 2010
magnitude 7 focal depth only 13km from port adu prince
200,000 deaths
250,000 homes destroyed
8 billion dollars in damages
medical response crippled by collapse in ifasturcture
58 million sent in forieng aid by ngos in the first day
2010 eujakfolikal eruption
- ash cloud from volcanic eruption melting glacier
-shield volcano
-4.7 billion lost line industry lost 20 million per day
-no deaths - all flights grounded or rerouted in
Europe (around 100,000)
seismic activity and and bulging crustal
features of a shield volcano
- shield volcano
-effusive lava (runny, basaltic)
-not explosive
what is palyomangetisim
-
Pinatubo
- ## Philippines
whay is the benioff zone
area where the plates colide with each otehr
what are p waves
conpression in the crust or mantle
what are s waves
shakes in the crust of mantle
L waves
move along the surface
