Question

unit 6 day 1 warmup
name
block

1. what is one method scientists use to map the topography of the ocean floor?

a. take pictures with satellites
b. reflecting sound waves off the bottom (sonar)
c. underwater drones
d. visual inspections by divers

1. what is created when two ocean plates move away at a divergent plate boundary?

a. ridge
b. trench
c. volcano
d. subduction zone

1. what is formed when a hot spot in oceanic crust allows magma to reach the surface and erupt?

a. abyssal plain
b. continental slope
c. volcanic islands & seamounts
d. mariana trench

1. what is the part of the continent called that is underwater?

a. continental shelf
b. continental slope
c. abyssal plain
d. oceanic ridge

Explanation:

1. Sonar (reflecting sound waves off the bottom) is a common method for mapping the ocean floor. Satellites take pictures of the ocean surface, underwater drones are not the main method for large - scale mapping, and divers' visual inspections are limited in scope.
2. At a divergent plate boundary where two ocean plates move away, new crust is formed, creating a ridge. A trench is formed at a convergent boundary (subduction zone), a volcano can be formed at a convergent or hot - spot related area, and a subduction zone is a type of convergent boundary.
3. When magma from a hot spot in the oceanic crust reaches the surface and erupts, volcanic islands and seamounts are formed. An abyssal plain is a flat area of the ocean floor, a continental slope is the slope between the continental shelf and the abyssal plain, and the Mariana Trench is a trench (a type of convergent - boundary feature).
4. The part of the continent that is underwater is called the continental shelf. The continental slope is adjacent to the continental shelf (going down to the abyssal plain), the abyssal plain is a deep - ocean flat area, and the oceanic ridge is a divergent - boundary feature.

Answer:

1. B. Reflecting sound waves off the bottom (Sonar)
2. A. Ridge
3. C. Volcanic Islands & Seamounts
4. A. Continental Shelf