Section 4 Flashcards
What is the definition of sonar?
a system for the detection of objects under water and for measuring the water’s depth by emitting sound pulses and detecting or measuring their return after being reflected.
What is the definition of mid-ocean ridge?
a long, seismically active submarine ridge system situated in the middle of an ocean basin and marking the site of the upwelling of magma associated with seafloor spreading. An example is the Mid-Atlantic Ridge.
What is the definition of sea-floor spreading?
the formation of new areas of oceanic crust, which occurs through the upwelling of magma at midocean ridges and its subsequent outward movement on either side.
What is the definition of deep-ocean trench?
Oceanic crust is formed at an oceanic ridge, while the lithosphere is subducted back into the asthenosphere at trenches. The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor.
What is the definition of subduction?
the sideways and downward movement of the edge of a plate of the earth’s crust into the mantle beneath another plate.
