living with tectonic hazards Flashcards
how do tectonic plates move through convection currents
The heat of the core causes the rocks in the mantle to melt to form magma. The magma rises and spreads out beneath the plate. This causes the plates to be dragged along from each other. The hot magma then cools and sinks, pulling the plate along and brings the plates towards each other. This constant rising and sinking of the magma gives rise to convection currents that cause the plates to move
Explain oc oc divergence
As two oceanic pates diverge, the tensional forces will cause fractures to form at the plat boundary such as in the case of the american and eurasian plate. Sea floor spreading occurs when magma that rises at the zone of divergence cools and solidifies. As it cools and solidifies, it forms a ridge of new ocean floor called the mid-oceanic ridge. At various points along the ridge, magma builds up above the ocean to form volcanic islands.
Explain cc cc divergence
When continental plates diverge, the tensional forces will cause the plates such as the african nubian and african somalian plates to move apart. Crust material is stretched, causing fractures to form at the plate boundary in a process known as faulting. The land in between the two continental plate sinks, forming a linear depression known as a rift valley. Pieces of continental crusts towering above the rest is known as block mountains. volcanoes may also be found along rift valleys as magma rises through the fractures
Explain cc convergence
As two continental plates such as the indian and eurasian plates converge, neither of the plates subducts due to similar densities. instead, the compressional forces causes to plates to break, slide along the factures in the crust and fold, forming fold mountains. Layers of rock on the upper part of the crust are compressed together, and they fold upwards or sideways, creating fold mountains like in the himalayas.
Explain oc cc convergence
when an oceanic plate converges with a continental plate, the compressional forces will cause the denser oceanic plate to subduct beneath the less dense continental plate. A subduction zone forms, creating a deep oceanic trench along the plate boundary. The subduction of the oceanic plate causes the solid mantle material to melt and magma is formed. The magma rises through the mantle and crusts to emerge as volcanoes, while folding occurs at the edge of the thick continental crust to form fold mountains.
explain oc oc convergence
at the oceanic-oceanic plate boundary, the compressional forces caause pacific and philippines plate to converge. The denser pacific plate subducts beneath the less dense philippine plate. A deep oceanic trench called the marina trench is formed at the subduction zone. The subduction of the oceanic plate causes the solid mantle material to melt and magma is formed. The magma rises through the crust to emerge as volcanoes. Eventually, volcanic island arcs like the mariana islands are formed.
