When we hear about volcanoes, we immediately think of fire-breathing mountains, spewing out clouds of ash, thousands of volcanic bombs and streams of hot lava. Such pictures are typical for volcanoes located on land, but not everyone knows that there are many more active and extinct volcanoes at the bottom of the World Ocean than on all earthly continents.
Underwater volcano West Mata in the Pacific Ocean
Newborn Islands
It would seem that in our time, geographical maps no longer need any changes, all continents and even the tiniest islands have long been discovered, with the help of aerial photography and satellite images, their contours and coordinates have been clarified.
However, the Earth is not a dead space body, it continues to live actively, and new islands that appear from time to time on the surface of the ocean are proof of this. Their birth is associated with underwater volcanic activity, which is especially intense in the Pacific Ocean.
At the moment, about two hundred cases of underwater volcanic eruptions have been recorded, which ended with the appearance of new islands on the ocean surface. True, not all "newborns" managed to resist the onslaught of waves, storms and underwater currents, only a quarter of the emerging islands "survived" and ultimately ended up on geographical maps. Here are just a few examples of islands that have risen from the depths of the sea.
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In 1796, in the Aleutian archipelago, an underwater volcano in the process of eruption so much increased its height that it rose above the surface of the ocean. Within a few years, the area of the volcanic island reached 30 sq. kilometers and it was named the island of John the Theologian (theological island). The island is reported to have appeared and disappeared periodically. The last time its "revival" was recorded in 1910.
In 1883, next to this island, another volcanic island rose out of the water and was connected with it by an isthmus. The process of the birth of islands in this place did not end there; after a few years, three more volcanic islands rose from the water to a height of up to three hundred meters.
Island of John the Evangelist. Navarino region of the Bering Sea. November 1976
In 1974, underwater volcanism helped Japan expand its territory a bit. That year, at a distance of 1000 km from Tokyo, a volcanic island with an area of 205,000 square meters rose from the water. meters, named Nishinoshima. The island belongs to the Ogawasara island chain. Since then, it has been constantly increasing its size.
Nishinoshima in 1978
After some time, after the assurances of volcanologists and oceanologists in its stability, it was included in the territory of Japan. As of November 20, 2015, the length of the island from west to east is 1,850 meters, and from south to north - 1,900 meters. The highest point of the island is about 100 meters above sea level.
In 2015, a new island appeared in the South Pacific Ocean - it happened thanks to the eruption of the underwater volcano Hunga Haapai. The island is located 45 kilometers from Nuku'alofa, the capital of the Kingdom of Tonga.
The island is 1.8 kilometers long and 1.2 kilometers wide, but scientists warn about its instability: the island can crumble into pieces and sink to the bottom of the sea. It consists mainly of volcanic slag: a dark rock where crystals are sometimes found.
The eruption of an underwater volcano near the state of Tonga, clouds of steam, ash and smoke reach 100 meters in height (March 18, 2009)
Before the Hunga Haapai eruption in 2015 and after
Asphalt volcanoes
Back in the 20th century, scientists found that there are much more underwater volcanoes on our planet than those located on land. They counted about 32 thousand volcanoes under water, and only 1.5 thousand on land. The Pacific Ocean became the real record holder for the number of underwater volcanoes, as it turned out when summing up the results of the International Geophysical Year.
According to a number of scientists, this was one of the most amazing discoveries of the last century. It was also found that the activity of underwater volcanoes is much higher than that of above-water ones. Almost all the mountains at the bottom of the oceans were volcanoes, active or already extinct. Scientists managed to discover a system that unites land volcanoes with their underwater cousins, it was called the Pacific Ring of Fire.
Pacific volcanic ring of fire
In addition to the very common and quite common underwater volcanoes, scientists 10 miles off the coast of California have managed to discover a number of unique asphalt volcanoes that have not had analogues until now. These volcanoes are about 40 thousand years old, the largest of them is at a depth of 220 meters; not surprisingly, it was discovered quite recently.
The volcanoes are slightly higher in height than a six-story building, and their base in area may exceed a football field. They are entirely composed of asphalt and, according to scientists, were formed as a result of a series of large portions of hydrocarbons entering the Pacific Ocean floor.
Oil splashing onto the ocean floor solidified, forming bitumen cones. To study the unique natural formations, scientists first used the Alvin research submarine, diving on it directly to the volcanoes.
Asphalt volcano at the bottom of the Gulf of Mexico
Then, with the help of a remotely controlled underwater vehicle with a manipulator, volcanic rock samples were taken. It turned out to be very fragile and easily crushed to the state of "thick oil", which can be used to obtain energy.
Scientists believe that at the same time as oil on the ocean floor there was an abundant release of methane, a greenhouse gas. According to researchers from the University of Santa Barbara, it was the intense release of methane in these volcanoes that could be one of the reasons for the start of the Ice Age.