Plates of the Lithosphere and it's theories part 2 Flashcards
Transform boundaries happens when two plates by shear force slide right past one another, which is why part of California is drifting toward Canada. What is an example of this?
Orchards & fences being offset
Plate movement is initiated by:
convection
What is the mechanism for plate motion?
Convection currents
What are convection currents?
hot magma that rise toward the surface pushing plate apart.
What is Isostasy?
Equilibrium between Earth’s crust & atmosphere such that the lithospheric plates “float”
What two types of volcanoes do we get from the the subduction process caused by convergence and divergence?
Ocean -> Ocean (basaltic (low silica)
Ocean -> Continent (combination silica rich and silica poor.
What are the 3 types of volcanoes?
Active Volcano
Dormant Volcano
Extinct Volcano
What is an active volcano?
a volcano that consistently erupts
What is a dormant volcano?
no evidence of recent eruption
What is an extinct volcano?
a volcano that has moved off of its magma source or the magma source died
What are the 3 factors that determine how violent a volcano’s eruption will be?
Composition, temperature, and dissolved gasses o the magma.
When thinking about properties of magma, what does a volcano high in viscosity mean?
it is pyroplastic or high in silica, highly explosive
What are the 3 volcanic land forms?
Calderas, Composite, and Lahars
What are Calderas?
a magma chamber that erupts and then collapses on itself.
ex. the Cascades in Oregon
What are composite volcanoes?
Most violent and explosive volcano composed of alternating layers of lava and pyroplastic.
ex. Mt, Raynier
Pyroclastic flow is:
composed of hot ash, pumice, rock fragments, and gasses. High in viscosity and can flow very fast.
ex. Pompay
A Lahar is:
viscous mudflow of materials such as pyroclastic debris and water. May be triggered by rapid snow melting or rainfall.
Where is the famous “super volcano” located?
Yellowstone
Indications that a volcano is going to erupt:
Frequent earthquakes, growing bulge due to rising magma chamber, and increased gas emissions.
What is a shield volcano?
occurs in O->O and is the board, gentle sloping of magma lo in silica that is slowly coming to the surface.
What is an example of a shield volcano?
Pahoenoeiha
Where is a very unusual location that a shield volcano has been spotted?
Hint: Think outside the box
Mars
What is an example of a shield volcano located on earth?
Mauna Loa
What happens when a volcano like the ones in the island arc, move off of their hot spot.
the volcano dies and become extinct
What happens when Lithospheric plates move across a hot spot?
an active volcano is produce
