Scientists discover why earthquakes strike stable regions like Utah and Groningen. Ancient healed faults can suddenly slip when disturbed, causing rare quakes. Study reshapes seismic risk for geothermal and energy storage projects.
Earthquakes in places long believed to be geologically stable — such as Utah in the U.S., Soultz-sous-Forêts in France, and Groningen in the Netherlands — have puzzled experts for years. Traditional geology taught us that shallow faults in these regions should strengthen as they move, preventing sudden slips and quakes. Yet tremors still happen. Their findings are recently published in Nature Communications.
Now, groundbreaking research from Utrecht University reveals why.
Sleeping Faults Aren’t Gone — They’re Charging Up
The new study explains that ancient faults, untouched for millions of years, quietly “heal” deep underground. Over time, this healing causes the rocks along the fault to bond and harden, building tremendous stress.
When activities like drilling or fluid injection disturb these re-strengthened faults, they can suddenly snap — unleashing a rare but powerful quake in areas historically considered safe.
Lead researcher Dr. Ylona van Dinther calls these zones “surprising hotspots,” where shallow earthquakes originate just a few kilometers below the surface — right where human operations often take place.
One Big Quake — Then Calm Again
Unlike typical seismic zones where repeated quakes occur, researchers found these events are one-time releases. Once the fault slips and stress is discharged, the region becomes more stable.
That means while the first quake can be jarring — especially since shallow quakes shake buildings more violently — the danger gradually fades afterward.
Safe Energy Future? This Research Matters
From geothermal plants to underground energy storage and carbon capture, the world increasingly depends on the Earth’s subsurface. This discovery reshapes how risk is assessed for future energy projects.
Scientists are now developing new earthquake-forecasting models to better pinpoint safe locations and communicate one-time seismic risks to communities and industries.
This breakthrough turns what once seemed geological “mystery quakes” into a crucial clue for safer renewable-energy expansion.