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ChromaDepth
Section I: A Tour of Planet Earth
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The Pacific Rim
Description: The Pacific Rim is important to the San Diego area in terms of trade, culture, and immigration. It is also geologically fascinating.
Things to Notice:
- The Pacific Rim is often called the “Ring of Fire”. This is because of all the tectonic plate activity in this area that results in earthquakes and volcanoes,
as the Pacific plate itself is consumed by all the surrounding plates.
- You can see a lot of the trenches (really deep, dark blue areas) right by the arc volcanoes like the Aleutians and Japan. The Pacific plate goes down, melts,
and molten material comes up in shape of arc to form volcano chains.
- The motion of two plates converging produces major earthquakes at these boundaries.
- Tokyo occurs at the boundary of three plates. Danger from earthquakes is thought to be particularly high here.
- There are many horizontal cracks in the Pacific Plate. This is because the Pacific Plate was formed and moves in segments. These transform faults separate regions
of different motion all of which is “frozen” into the crust after it forms.
- What we think of as the Hawaiian Island are really just the recent tip of a long chain of undersea mountains that stretch for hundreds of miles, getting slowly deeper
until they disappear beneath the Aleutian Islands.
- The big bend in the Hawaiian Islands, which is called the Emperor seamount chain to the north of the bend, is thought to have been produced by a global change in plate
motions when India ran into Asia. This is like two cars hitting each other and then their combined motion makes them spin. The Pacific plate changed motion when India and
Asia collided. The Hawaiian-Emperor seamount chain records this.
- The Southeastern end of the Hawaiian chain is the highest and hottest (balloon analogy). As you go to the north, the seamounts (old volcanoes) get deeper and deeper
beneath the surface of the ocean.
- The Bering Strait that separates Russia’s Siberia from America’s Alaska is really part of the continental shelf shared by both continents, and thus is relatively shallow
compared with the rest of the Pacific Ocean.
Go back to Section I here
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