Groundwater May Be Key to Earthquake Warning System

(CN) – Elevated helium levels in groundwater could signal impending earthquakes, potentially giving authorities time to prepare strategies to minimize property damage and deaths.

Japanese researchers examined the relationship between helium levels in groundwater and the level of stress exerted on the inner rock layer of the earth at locations near the epicenter of the 2016 Kumamoto earthquake, a magnitude 7.3 quake in southwestern Japan that killed 50 people and caused significant damage.

The team hopes their findings – published Tuesday in the journal Scientific Reports – will encourage the development of a monitoring system to measure stress changes that foreshadow a massive earthquake.

High levels of stress exerted on the earth’s crust led to more helium being released in the groundwater at sites near the epicenter of the 2016 quake, according to their findings. The researchers pumped groundwater samples from wells at depths of 920 feet to 4,265 feet, from seven different locations.

They then compared helium levels in chemical analyses performed in 2010 with samples from near the Kumamoto earthquake, connecting the elevated levels in the 2016 samples to chemical changes that foreshadowed the quake.

“After careful analysis and calculations, we concluded that the levels of helium-4 had increased in samples that were collected near the epicenter due to the gas released by the rock fractures,” lead author Yuji Sano said.

The team found that helium concentrations were lower further away from the most intense seismic activity.

Previous studies have 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 12.5 miles from Kobe, Japan – a city of about 1.5 million people – and caused 6,434 casualties and roughly $200 billion in damage.

However, scientists needed more evidence to firmly link the occurrence of earthquakes with chemical changes in groundwater before confirming a correlation. And while Sano’s study adds to body of evidence, the University of Tokyo professor said more studies are needed.

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