Japanese researchers at the University of Tokyo have conducted several studies, including some following the earthquake in Kobe in 1995. The studies indicated that the stress on the Earth’s crust increases when the levels of underground helium increases.
Scientists have noticed a correlation between the rise in the levels of helium in groundwater and the stress on the inner rock found near the epicenter of the Kumamoto earthquake in 2016; a magnitude 7.3 quake in southwestern Japan, which resulted in 50 fatalities and serious damages. Groundwater samples were obtained through submersible pumps in deep wells at depths 280–1,300 meters from seven locations in the fault zones surrounding the epicenter eleven days following the earthquake in April 2016. They were compared to previous samples obtained in 2010 from identical analyses.
Scientists not only revealed that the levels of helium-4 had risen in rock samples collected near the epicenter due to the gas released by rock fractures, but also estimated the amount of helium released through fracture experiments in the laboratory. Furthermore, they calculated the amount of strain exerted at the sites for groundwater sample collection using satellite data. The outcomes of these analyses have shown a relation between helium amounts in groundwater and the stress exertion, where the levels of helium have increased in the sites near the epicenter. The team found that helium concentrations were lower further away from the most intense seismic activity.
This means that there is a form of helium known as helium-4 that is trapped under the Earth’s crust; when much stress is exerted on the crust, rock layers fracture, allowing helium gas to escape through the cracks, where some of it becomes trapped by the water in and on the ground. As such, by simply monitoring the levels of groundwater helium, the outbreak of earthquakes could be detected, giving the inhabitants enough time to evacuate and spare the lives of many.
Previous studies had found that changes to the chemical makeup of groundwater might occur before earthquakes, including some following the Great Hanshin quake in 1996. That quake’s epicenter was about 20 kilometers from Kobe, Japan—a city of about 1.5 million people—causing 6,434 casualties and roughly USD 200 billion in damages. However, researchers still needed to collect evidence to link the occurrence of earthquakes to such chemical changes before establishing a strong correlation between the two. They need to have a base sample of the amount of helium present at a particular area; then, said area had to be hit by an earthquake, so that they can test helium levels afterwards.
The question now is where to seek out places to establish baseline groundwater helium levels. It is possible that areas along a fault line are more likely to be hit by earthquakes and helium levels could be tested in the groundwater there, but it still seems a bit “hit or miss” as a means to establishing a true earthquake prediction solution.
“More studies should be conducted to verify our correlation in other earthquake areas”, says Sano, the study’s lead author. He continues, “It is important to make on-site observations in studying earthquakes and other natural phenomena, as this approach provided us with invaluable insight in investigating the Kumamoto earthquake”.
This relation between groundwater helium levels and earthquakes, if proven, would help scientists develop a system that detects stress changes, which could foreshadow any upcoming earthquakes.
The field of scientific research is literally the gift that keeps on giving; there will always be a new theory to test, and a new discovery to be made. A key warning for earthquakes, one of nature’s most potentially devastating disasters that could happen anywhere, anytime, could be a major lifesaving breakthrough and gift of Earth sciences.
References
askzephyr.com
courthousenews.comsciencedaily.com