Difficult to predict volcanic eruptions. The ratio of atoms in specific gases released from volcanic fumaroles can provide an indicator of what is happening to the magma deep below. Things might be heating up.
The risk of different types of eruption can be indicated by changes in the ratio of the two gases. It's important to understand the ratios of gases that indicate a certain type of activity. The team wants to develop portable equipment that can provide real-time volcanic activity monitoring and early warning systems.
Is standing on a volcano exciting or frightening? Many people live in the shadow of a volcano every day. Every year there are an average of 15 volcanic events in Japan. These events can be deadly.
58 people were killed and five were missing when Mount Ontake, Japan's second-highest volcano, unexpectedly erupted. The Japan Meteorological Agency would benefit from other reliable ways to forewarn residents of the next potential disaster due to the fact that some eruptions can occur without clear earthquake signals.
Gas and steam can be released from holes and cracks in the Earth's surface. There is a mix of chemicals. Its composition can give us insight into what is happening below the Earth's crust in the mantle, wheremolten rock forms and pushes upwards. The ratio of isotopes in certain gases can indicate hidden magma activity.
When the activity of magma increases, the helium ratio in the Earth's mantle can change from a low value to a high one. In the Canary Islands, in the Atlantic Ocean off the northwestern coast of Africa, an eruption took place in 2011. We did not know why we had more mantle-derived helium.
The Kusatsu-Shirane volcano lies about 150 kilometers northwest of Tokyo in Gunma Prefecture and has six fumaroles. Every few months the team collected samples. They used state-of-the-art equipment to analyze the samples after they were collected. They were able to measure the isotopic composition of ultratrace, which is more abundant in the mantle than in the air.
Changes in the magma-derived argon-40/helium-3 ratio were detected by us. Using computer models, we were able to show that the ratio reflects the amount of magma underground which makes bubbles of volcanic gases.
How much magma foams affects how much magmatic gas is delivered to the volcano and how much is deposited into the ground. There is a risk of phreatic eruption in which an increase in water pressure causes the eruption. A magmatic eruption would result from the latter increasing the rate of ascent.
When you compare a volcano with a human body, the methods used are similar to listening to the chest and taking body size measures. It's hard to know what a health problem is when you don't have a medical checkup. The chemical composition of elements in fumarolic gases can be compared to a breath or blood test. We are looking at actual material derived from magma to know what's happening with it.
Gas samples have to be collected out in the field and brought back to the lab to be analyzed. Sumino hopes to develop a new tool that will allow them to perform the same analysis in real time and out in the field.
"We want to be able to detect changes in activity as soon as possible." Real-time monitoring of noble gas isotope ratios from fumarolic gases is in the works. To make it a reality that all active volcanoes are monitored 24 hours a day, seven days a week, we need to establish a noble gas analysis protocol.
Scientific Reports publishedMonitoring of magmatic-hydro-thermal system by noble gas and carbon isotopic compositions of fumarolic gases
Monitoring of magmatic-hydro-thermal system by noble gas and carbon isotopic compositions of fumarolic gases is a report. www.nature.com/articles/s41598-022-2
Journal information: Scientific Reports
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