Scientists looking for new hydrothermal sources in the Pacific have made an important discovery. They have discovered a relatively new volcanic eruption in the Mariana Back-Arc of the western Pacific. It is about 14,700 feet below the surface, making it the deepest volcanic eruption ever seen on Earth.
By comparison, it lies deeper below the sea surface than the height of Mount Rainier above sea level.
"We know that most of the world's volcanic activity actually takes place in the ocean, but most of it remains undetected and invisible," said lead author Bill Chadwick, a marine geologist at Oregon State University and NOAA's Pacific Marine Environmental Laboratory. "That's because underwater tremors associated with volcanism are usually small, and most of the instrumentation is far away on land, many of these areas are deep and leave no trace of the surface, which makes submarine eruptions very much elusive. "
All of this changed as researchers employed advanced technologies and exploration methods. They have discovered evidence of about 40 underwater eruptions since 1
The latest discovery is based on data collected from the remote-controlled vehicles Deep Discoverer and SuBastian. The combined ROV data provided new insights into this under-explored world of underwater volcano.
Researchers had the first opportunity to see this submarine volcanic eruption in the Mariana Back-Arc in December 2015 while using the cameras to board the area on an autonomous submersible, Sentry. Initial photos showed the existence of a pristine, dark, glassy lava flow on the sea floor with continuous ventilation of the hydrothermal fluid, suggesting that the lava was still warm and therefore very young.
When the researchers returned to the site in April and December 2016, they noticed major depth changes in the area. The new lava flows extended over an area of about 4.5 miles in length and between 130 and 450 feet in thickness.
"Typically, after an eruption, heat is released and drained for several years and organisms will colonize the new ecosystem vents," said Chadwick. "But after a while, the system cools down and the mobile organisms will disappear, there was still a vent, but it obviously went down a lot."
Underwater volcanic eruptions can dramatically change their environment. The detailed investigation of the deepest underwater volcanic eruption provides a more detailed insight into the interior of submarine volcanoes and their effects in the ocean.
"Submarine volcanoes can help us to inform us about the functioning of terrestrial volcanoes and their effects on ocean chemistry, which can significantly affect local ecosystems," said Chadwick. "It's a special learning opportunity if we can find it."