Researchers at the University of Tokyo and their collaborators have revealed a relationship between helium levels in groundwater and the amount of stress exerted on inner rock layers of the earth, found at locations near the epicenter of the 2016 Kumamoto earthquake.
Scientists hope the finding will lead to the development of a monitoring system that catches stress changes that could foreshadow a big earthquake.
A team of researchers at the University of Tokyo and their collaborators found that when stress exerted on the earth’s crust was high, the levels of a helium isotope, helium-4, released in the groundwater was also high at sites near the epicenter of the 2016 Kumamoto earthquake, a magnitude 7.3 quake in southwestern Japan, which caused 50 fatalities and serious damage.
Furthermore, scientists estimated the amount of helium released by the rocks from the change of helium content in groundwater based on certain assumptions.