They went hunting volcanoes from space. A team of scientists set out to underwater map Earth’s oceans using high-resolution radar satellites. More than 19,000 volcanoes have been discovered during this study.
Oceans… Although they occupy more than 70% of the Earth’s surface, they are still poorly understood, and the underwater landscape is not yet accurately mapped. Until now, sonars have mainly been used to map the sea surface. This technique generates sound waves to detect obstacles in water. Yet, despite the best efforts of scientists, it is estimated that only a quarter of the ocean floor has actually been mapped in this way. Countless landmasses still lie dormant underwater, occasionally colliding with unlucky submarines.
The scientists behind the discovery of these 19,000 new volcanoes used a different technique. In fact, radar satellites that measure the height of the oceans can also give us information about the ocean floor. To do this, scientists observe subtle variations in the surface of areas of oceans located above significant relief. In 2011, the first census was already conducted using this technique. This made it possible to find about 24,000 “seamounts”. Seamounts are seamounts formed by volcanic activity.
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To carry out this new study, scientists used high-definition radar satellites, which were able to add 19,000 seamounts to the hunting table. Thanks to the high accuracy, scientists believe that the height of small underwater volcanoes can be estimated with an accuracy of about 370 meters. Among the summits identified by these two “scans,” 27,000 seamounts have never been mapped by sonar. ” It’s amazing David Sandwell, a marine geophysicist at the Scripps Institution of Oceanography who participated in the study, said.
In a scientific article.
Understanding submarine summits to understand climate change
The researchers extracted data from several satellites, including the European Space Agency’s (ESA) CryoSat-2. According to the article, they were able to detect sea ridges up to 1,100 meters high, which is the lower limit of “beach”. Science. From their analysis they drew up a new “list” listing these reliefs. So this is the most comprehensive document ever produced on the subject. It was published in the magazine on April 6 Earth and Space Sciences.
Two seamounts from the Kim-Wessel table before and after centering (20 Edvos’ contours). The light blue dots indicate the original location of the seabeds. The red points are the new centers selected according to the maximum value of the vertical gradient of gravity.
This information is valuable to scientists because the presence of these landscapes tells us more than we think at first glance. Indeed, the study of these submarine “volcanoes” provides a better understanding of ocean currents and plate tectonics. It also provides clues about climate change: ” They are catalysts that help regulate large-scale ocean currents that are responsible for sequestering large amounts of heat and carbon dioxide John Lowell, chief hydrographer for the National Geographic Intelligence Agency (NGA), which manages the U.S. military’s satellite mapping efforts, told the press. Science. ” The better we understand the shape of the ocean floor, the better we can prepare [au changement climatique] “.
Incredible oases for many species, these mountains are fascinating from a biological point of view. In other words, this list should be published by many scientists of all stripes. ” There are interesting things that happen when you have a landscape “, explains
Science Brian Orbick, a physical oceanographer at the University of Michigan in Ann Arbor, who was not involved in the study.
Source: Earth and Space Sciences
