tectonic plates: gateway 1

Question 1

oceanic-oceanic divergence

Answer 1

• oceanic north American plate diverges from the Eurasian plate to form the MID ATLANTIC RIDGE
• when the oceanic north american plate diverges from the oceanic eurasion plate
  > tensional force is exerted
• as magma rises through the cracks and fissures at the zone of divergence, the cool and solidify to form new sea floor through the process of sea floor spreading
  > a linear ridge is formed which is known as the mid oceanic ridge
  > at various points along the mid oceanic ridge magma may continue to exploit the cracks and fissures along the linear ridge to form submarine volcanoes
• submarine volcanoes may rise above the surface of the water, forming volcanic islands

Question 2

continental-continental plate divergence

Answer 2

• when the continental nubian plate and the continental somalian plate diverges
  > EAST AFRICAN RIFT VALLEY is formed
• when the plates diverge, the continental crust is stretched
  > the tensional force causes fault lines and fractures to form at the plate boundary
  > blocks of land masses will be displaces and subside along the faultlines
  > forming a linear depression
  > the EAST AFRICAN RIFT VALLEY

Question 3

oceanic-oceanic plate convergence

Answer 3

• when the oceanic pacific plate and the oceanic philipenes plate converges
  > MARIANA TRENCH is formed
• when two plates converge, compressional force is being exerted
  > the denser oceanic plate sinks beneath the less dense oceanic plate
• at the point of subduction, linear depression is formed
  > the OCEANIC TRENCH is formed on the seafloor
• part of the subducted plate melts to form magma
  > magma rises through the cracks and fissures to the earth’s surface to form submarine volcanoes
  > due to multiple eruptions, the submarine volcanoes rises above the surface of the water to form volcanic islands

Question 4

continental-continental convergence

Answer 4

• as the indian plate converges with the eurasion plate
  > the HIMALAYAS is formed
• when the two continental plates converge, compressional force is exerted
  > since the two plates are similar in density and are light and buoyant
  > they resist subduction during convergence
  > the edges fold and buckle upwards and sideways to form a series of fold mountains

Question 5

oceanic-continental convergence

Answer 5

• the oceanic australian plate and the continental eurasion plate
  > SUNDA TRENCH

1. when the oceanic plate converges with a continental plate
   > compressional force is exerted
2. the denser oceanic plate subducts beneath the less dense continental plate
3. at the point of subduction, an oceanic trench is formed
4. part of the subducted plate melts to form magma
5. as the magma rises through the cracks and fissures of overlying plate, a volcano is formed
6. the edges of the continental plate folds and buckles upwards and sideways

Question 6

transform plate boundaries

Answer 6

• San Andreas fault between the Pacific plate and the North American plate
• in 1960s, an earthquake occurred in San Francisco at the San Andres fault
  > caused several hundred kilometers of the North American plate to move an average of 2.5 meters, and at one point almost 7 meters in less than one minute