A new study reveals that the largest active underwater volcanic eruption ever recorded in 2018 has given birth to a large “baby”: an underwater volcano the size of a skyscraper.
Scientists have discovered a 2,690-foot (820 m) volcano off the coast of Madagascar, near a normally peaceful area in the western Indian Ocean. After collecting geographical data in 2019, including data from an underwater survey of the area, the team identified the new underwater volcano as 1.5 times larger than the New York volcano. A World Trade Center. Also, this new “baby” comes from a deep reservoir of volcanic magma known to scientists.
“The source of the magma, the reservoir, is very deep,” said Natalia Foyer, a marine geologist at the Paris Institute of Geophysics (IPGP) at the University of Paris, about 34 miles (55 km) underground. “This is the first time in volcanology that we can see such a deep body of water at the bottom of the lithosphere,” says the Earth’s crust, including the upper shell and crust.
Related: Photos: Brilliant lava flows from the Kilauea volcano in Hawaii
Between May 2018 and May 2021, more than 11,000 earthquakes shook the small island of Mayotte and the French territory between Madagascar and Mozambique. It was the strongest earthquake with a magnitude of 5.9, but it was not Strange earthquakesOr very low frequency earthquakes that occur deep in the earth; It cannot be felt on the surface, but it is understood by seismologists around the world. These low-frequency earthquakes are associated with volcanic activity.
Since only two earthquakes have been recorded near the island of Mayotte since 1972, this sudden earthquake was astonishing, and so far the last volcanic activity – the pumice layer of the lake near the island – has survived for at least 4,000 years, the researchers wrote in the study.
In July 2018, scientists discovered that the Mayotte was moving 7.8 inches (20 cm) eastward, according to GPS data. At the time, there were only three or four GPS stations on the island, so scientists set up global navigation satellite systems and seismic records at the island’s sea level to learn more about geographical changes. The results were extraordinary: between February and May 2019, researchers found that land and sea seismometers recorded 17,000 events.
Sea voyage
In May 2019, Willett and her colleagues had the opportunity to sail on the research ship Marion Dufresne. The team knew there was a rock east of Mayotte, but they were not sure if the magma continued deep into the crust or leaked into the sea.
“We were expecting to see something, but it wasn’t clear,” Foyer said.
In 2019 MailShe wrote: “We have developed a protocol for the analysis of seismic signals recorded by OBS. [ocean-bottom seismometers]. Working full time, in shifts, the teams were able to accurately detect 800 earthquakes (on a scale of 3.5 to 4.9) in two weeks. ”
Their efforts paid off: “We found that most of these earthquakes were very close to the island (10 km). [6 miles] From the east coast of the island), but it was deeper (20 to 50 km) [12 to 31 miles] Deeply), ”Foyers wrote.
The ship’s multi-beam echo probe sends sound waves to map the coastline and water column, and then finds something “very large” 31 miles east of Mayotte, Voulette said. It was a pyramid-shaped underwater volcano measuring about 1.2 cubic miles (5 cubic kilometers). This volcano was completely new; According to a previous survey by the French Naval, Hydrographic and Oceanographic Service, this was not the case in 2014.
According to a 2014 survey, the area is “almost flat – about 3,300 square meters [10,827 feet] Below sea level.
These volcanic eruptions are 30 to 1000 times larger than other recorded deep-sea eruptions. This is three times the size of the Howrah eruption in New Zealand in 2012, and 2.5 times the size of the Bardarbang eruption in Iceland in 2014, the largest eruption in 200 years.
it seems Tectonic plates This movement caused lava to grow in the asthenosphere, the molten layer on top of the shell just below the thick lithosphere. This magma flows into geological dams, which may explain the earthquake and the subsequent large eruption.
Moreover, this eruption does not appear to be the first near the Mayotte. “Large pyroclastic flows and angles on the upper slopes and on Mayotte Beach indicate that this occurred in the past,” the researchers wrote in the study.
The team is monitoring the area for more earthquakes and volcanic activity. “It’s still exploding,” Foyer said. The last evidence of submarine lava is in January 2021. “
The study was published in an online journal on August 26 Natural geosciences.
First published in Live Science.
Prone to fits of apathy. Unable to type with boxing gloves on. Internet advocate. Avid travel enthusiast. Entrepreneur. Music expert.
