With an estimated 300 active volcanoes on Earth, the challenge is how to monitor them all to send out early warnings before they erupt. Measuring volcanic emissions is also not easy.
Now researchers have designed specially adapted drones to help collect data from an active volcano in Papua New Guinea (PNG).
Drones can help the local community monitor nearby volcanoes and forecast future eruptions. Their measurements can also tell us more about the most active, inaccessible volcanoes on the planet and how volcanoes contribute to the global carbon cycle.
The volcanic Manam is located on an island only 10 km (6 miles) wide that sits off the northeast coast of PNG. The island is home to more than 9,000 people and Manam Motu, as is known locally, is one of the most active volcanoes in the country. In 2004, a massive eruption from Manam forced the entire island to be evacuated to the mainland and devastated the people’s crops and homes.
Scientists have several ways of predicting when a volcano is about to explode. They can monitor earthquake activity in the area to detect tremors that almost always occur before eruptions and look for bulges in the volcanic steep walls as magma accumulates below.
When clear skies allow, satellites can also quickly detect and measure volcanic emissions such as sulfur dioxide (SO2). Changes to these emissions could signal more activity in the volcano below.
“Manam has not been studied in detail yet but we can see from satellite data that it is generating strong emissions,” said volcanist Emma Liu from University College London, who leads the team of scientists. earth school and aerospace engineer, said.
“We [also] want to quantify carbon emissions[s] from this huge source of carbon dioxide, “added geochemist Tobias Fischer, from the University of New Mexico.
Although volcanoes only emit a small portion of the carbon emissions that humans emit, researchers still want to be able to estimate the amount of carbon dioxide (CO2) they emit, so that they can be counted towards their carbon budget. We have the remaining to limit the impact of climate change.
To PNG, the international team prepared to test two types of long-range drones equipped with gas sensors, cameras and other equipment during two field campaigns on Manam Island, in October. 2018 and May 2019.
Manam’s steep slopes make it extremely dangerous to collect gas samples by walking while the drone can safely fly into the rolling cloud, helping the team measure the amount of gas. volcanic emissions more precisely.
The UAVs flew over 2,000 meters (6,561 feet) high into the chaotic Manam flames and about 6 km (3.7 miles) away from their launchers, also out of their pilot’s line of sight.
On each flight, the drone takes a picture of Manam and its two craters, measures the gas composition right above the bursts of gas and collects four bags full of excess air for quick analysis as the plane lands.
The drone images show that Manam’s southern crater degassing intensified from October 2018 to May 2019. In fact, the volcano soon erupted in June. , just a month after the researchers’ second field trip.
But increased volcanic emissions are not only a reliable indicator of whether an eruption is imminent or likely to occur, so the researchers have also looked at the ratio between other gases. each other, namely CO2 and SO2, in Manam’s smoke beam.
This could help detect hot magma rise on the surface and remove CO2 rich emissions reported prior to large eruptions.
However, the researchers found that the mixture of manam emissions was the same during both field trips.
Integrating their drone measurements with satellite data, researchers can point out that Manam ranks among the top 10 most powerful degassing volcanoes in the world, emitting around 3,700 tons of CO2 and about 5,100 tons of SO2 per day – higher than previous estimates.
The team also deduced that most of Manam’s emitted carbon could be derived from the upper mantle rather than from the Earth’s shallower crust, which they found by analyzing carbon isotopes. different in the gas mixture.
“Our new approach – it’s long range and high altitude [drone] Activities that allow for on-site measurement – are currently the only viable means by which we can characterize gasification in steep, dangerous and highly active volcanoes like Manam, “the team concludes in their articles.
Future research will require more effort from scientists and flight time from drones, as measurements from this study last only 10 days.
With enough funding to equip and train local scientists, this strategy can be used elsewhere to track other dangerous inaccessible volcanoes, such as the Mayon in Philippines and Sinabung in Indonesia.
Research is published in Scientific advance.
This article was originally published by ScienceAlert. Read the original article here.