Author Question: Multibeam echo sounders radiate multiple beams of sound pulses to give a larger coverage pattern on ... (Read 29 times)

123654777 · **on:** Aug 22, 2018

Multibeam echo sounders radiate multiple beams of sound pulses to give a larger coverage pattern on ocean
floors compared to the original single echo sounders.
a. True
b. False

Question 2

Outline how the formation of the Hawai'ian Islands contributed to the evidence of plate tectonics. What will be an ideal response?

blfontai · **Reply #1 on:** Aug 22, 2018

Answer to Question 1

True

Answer to Question 2

Hot spots are fixed areas where mantle rises to the surface. A volcano can form over the hot
spot, but because the plate is moving, the volcano is carried away from its source of magma
after a few million years and becomes inactive. It is replaced at the hot spot by a new volcano
a short distance away. A chain of volcanoes and volcanic islands forms as the oceanic plate
moves over the stationary mantle plume and hotspot. The age of the islands increases the
further removed from the hotspot. New islands continue to form over the hotspot. The
Hawai'ian Islands are the most famous of these assembly-line chains, which extends from
the old eroded volcanoes of the Emperor Seamounts to the still-growing island of Hawaii.
The abrupt bend in the chain was caused by a change in the direction of movement of the
Pacific Plate, from largely northward to more westward, about 40 million years ago. The next
Hawaiian Island that will come into beingalready named Loihiis building on the oceanfloor at the southeastern end of the chain. Now about 1,000 meters (3,300 feet) beneath the
surface, Loihi will break the surface about 30,000 years from now.