Join this channel to get access to perks:
https://www.youtube.com/channel/UCQ7uJQPoftJZW1nXczX8VGw/join

SOURCE: AMERICAN SAMOA NATIONAL PARK

The geology of the Samoan islands is surprisingly interesting. First, we are living on a volcano, which is resting at the moment. Second, our volcano is on the move – it’s traveling towards China. Finally and most unfortunately, our volcano will eventually sink back into the dark ocean depths. About 1.5 million years ago, our volcano spewed forth enough lava to rise up out of the ocean and become “Tutuila Island”. Actually, just the tip of the volcano is visible to us – most of the mountain is underwater. While the tallest mountain peak on Tutuila is about one half mile high, the mountain extends another 2-3 miles below the sea surface.
It is not much of an exaggeration to call the Samoan islands 'active volcanoes'. These islands were formed by volcanism, and the volcanoes are still active, in a geologic timeframe of course, and due to some unusual circumstances as described below. The most recent volcanic eruptions were not that long ago.
In Samoa, major eruptions occurred in 1905 when lava flows destroyed a village. In the Manu'a islands, subsurface volcanic eruptions and earthquakes occurred in 1866, causing dense clouds of smoke and pumice to erupt from the ocean surface for several months. One hundred years ago is just a blink of the eye to a volcano, which measures time in the millions of years. We tend to forget how briefly people have lived upon these shores. Human habitation on Tutuila, even considering the whole 3000-year period that Samoans have dwelt here, represents a mere 0.2% of the time since the sun first shone on this new land.
To explain our volcano's slow-motion march towards China, we first need to review the nature of the earth's surface or crust. The earth's outer layer, the one we live on, is several miles thick, but that is a thin skin compared to the total size of the earth. This outer layer is made up of many separate sections that seemingly float on top of the earth's molten core and move about in very slow motion. Geologists call these outer sections “plates”. You may recall, for example, that the continents of Africa and South America were once joined together when the earth first formed, but the two continents slowly drifted apart to where they are today. The same process applies to the plates under the Pacific Ocean. The plate we're on is called the Pacific Plate and it is moving westward (towards China) at a leisurely speed of about 3 inches per year. At this rate, in one million years we will be 50 miles closer to China.
It is not accidental that the islands of American Samoa and Samoa lie in a rather straight line. Directly underneath us is what geologists call a “hot spot” of thermal activity in the earth's core. It's a volcano just waiting to happen. When the pressure builds up at the hot spot, molten magma bursts up through the Pacific Plate and forms a volcanic island. Then the hot spot calms down for awhile, perhaps a million years or so. During this peaceful interval, the Pacific Plate keeps marching onward, so when the hot spot acts up again, it forms a new volcanic island rather than building upon the previous one. In other words, the hot spot stays in one place but the plate above it keeps moving. The islands generally lie in a straight line that is oriented in the direction the plate is moving. The new islands form on the eastern end of the chain, so the islands become progressively older as you move westward. For that reason, the islands in Samoa are about 1 million years older than the islands in American Samoa. The newest volcanic eruption in our island chain is forming about 30 miles east of Ta'u Island, but it will probably be another few hundred years before this sub-surface volcano, named Vailulu'u, breaks the sea surface (in 2005 it was 1800 feet below the surface and growing).

#volcano