Unraveling the Mystery Behind Seismic Events Triggered by Rapid Temperature Drops

Cryoseisms, also known as ice quakes, are geological phenomena caused by water infiltrating soil and rock, freezing, and subjecting the ground to significant mechanical stress. These events have been largely understudied and remain far more unpredictable than standard tectonic earthquakes. However, groundbreaking research by an international team of experts has now provided valuable insights into analyzing, assessing, and predicting the risks associated with cryoseisms.

Led by the Geological Survey of Finland, this collaborative study involved the Oulu Mining School of the University of Oulu and the University of Colorado at Boulder (USA). Under the guidance of Jarkko Okkonen, the scientists developed a cutting-edge mathematical-hydrological model that correlates thermal stress with the release of energy from an ice quake.

The team's research focused on cryoseismic events that impacted a Finnish municipality six years ago. By examining these occurrences, they were able to accurately deduce what transpired beneath the ground. The study's authors found that rapid temperature drops could cause thermal stress to exceed a material's mechanical resistance, leading to explosive ruptures, such as those caused by frozen water in rocks and saturated soils.

Cryoseisms produce loud, gunshot-like noises that emanate from the subsurface. Okkonen and his colleagues concluded that the ice quakes in Oulu were triggered by a swift temperature decline from -12°C to -29°C, a rapid decrease of 17 degrees. This dramatic change placed immense stress on saturated rocks and frozen ground, ultimately resulting in the explosive release of energy and the fracturing that damaged buildings and infrastructure.

By shedding light on the complex relationship between thermal stress and cryoseisms, this innovative research offers a promising foundation for future studies and risk assessments related to these unpredictable seismic events.