Slab Pull Flashcards
(12 cards)
What is slab pull and how does it affect tectonic plate movement?
Slab pull occurs when denser oceanic plates are subducted, creating a suction force that helps pull the plate further into the mantle. It is a major force driving plate movement.
Why does the Pacific Plate move faster than most other plates?
It has extensive subduction around its edges, contributing to faster movement due to slab pull.
What role do mantle plumes play in tectonics?
Mantle plumes buoy up the crust, leading to large-scale features like mid-ocean ridges. For example, a plume under West Africa may have formed the Mid-Atlantic Ridge and split continents.
What tectonic process is happening in East Africa?
The African Plate is splitting into the Nubian and Somalian plates, creating intra-plate earthquakes and volcanic activity.
What is a subduction zone?
It’s where two tectonic plates converge and the denser oceanic plate descends beneath a continental plate.
What is a megathrust fault?
A large fault at a subduction zone where locked plates build up stress and can release it suddenly in a mega-thrust earthquake.
What is the elastic-rebound theory?
It describes how stress builds on a locked fault over time, then is released suddenly in an earthquake when the frictional resistance is overcome.
What is a locked fault?
A fault that isn’t slipping because friction exceeds shear stress, storing strain that can be released in a large earthquake.
How was the 2004 Indian Ocean tsunami caused?
By a megathrust earthquake at a locked subduction fault where the Indian Plate was subducting, releasing decades of built-up strain.
What is the Benioff Zone?
A zone of seismicity within a subduction zone where the subducting slab generates intermediate and deep-focus earthquakes.
Why are locked faults significant hazards?
They can hold stress for hundreds of years and release it suddenly in large earthquakes, posing major tectonic risks.
Why is the western edge of the South American Plate called an Andean boundary?
Because it features a classic example of a subduction zone, where the Andes Mountains were formed.
