Cryoseism

A cryoseism, also known as an ice quake or frost quake, is a type of seismic event that happens when frozen soil or rock suddenly cracks. This usually occurs in areas where the ground is saturated with water or ice. When water seeps into the ground and then freezes during cold temperatures, it expands and creates stress on the surrounding soil and rock.

This built-up stress can eventually release explosively, causing what is known as a cryoseism. These events happen because of a number of specific conditions, which makes it difficult to predict them accurately. Because of this, they can be an important factor to consider when planning and building structures in areas where cryoseisms have occurred before.

There has been some discussion about how global warming might affect how often cryoseisms happen, though predicting these events remains challenging. Understanding cryoseisms helps scientists and engineers make safer decisions when building in cold regions.

Effects

Cryoseisms are often mistaken for minor intraplate earthquakes. They can cause tremors, vibrations, ground cracking, and loud noises like thundering or booming sounds. However, cryoseisms can be different from earthquakes because of their meteorological and geological conditions. They can have an intensity of up to VI on the Modified Mercalli Scale but usually affect only a small area around the epicenter. Some seismic stations might not record them because of their lower-frequency vibrations.

Some people report seeing distant flashing lights before or during a cryoseism, possibly due to electrical changes when rocks are compressed. Cracks and fissures can appear as the ground contracts and splits apart from the cold. These cracks can be a few centimeters to several kilometers long and may shift either vertically or laterally, known as displacement.

Occurrences

Glacial cryoseisms

A glacial cryoseism or glacial ice quake is a non-tectonic seismic event of the glacial cryosphere. Large calving events in Greenland and Antarctica can create seismic events of magnitude 5 or larger. Very big icebergs can also make seismic signals when they crash or move across the ocean floor. When water builds up under a glacier, it can lower friction and let the glacier suddenly shift, creating seismic waves. These events can be very short or last for many minutes.

Location

United States

Cryoseisms have been reported in the Midwestern, Northern and Northeastern United States. On January 26, 2026, after a big winter storm in Middle Tennessee, frost quakes were felt by many people there and in part of Southern Kentucky.

Canada

Cryoseisms happen in Canada, especially near the Great Lakes and St. Lawrence area. They have been noted in Ontario, Quebec, Alberta and the Maritime Provinces.

Other places

Glacier-related cryoseism events have also been observed in Alaska, Greenland, Iceland, Finland, Ross Island, and the Antarctic Prince Charles Mountains.

Precursors

For a frost quake to happen, several conditions must be met: the area needs to be able to get very cold, the ground must be wet from melting snow or rain before a cold snap, there usually needs to be only a little snow on the ground (less than 6 inches or 15 cm), and the temperature must drop quickly to near or below −18 °C (0 °F) over 16 to 48 hours. Cryoseisms often happen when temperatures fall rapidly from above freezing to below freezing, usually between midnight and early morning. Because glaciers are always cold, glacier-related cryoseisms can also happen in summer. These events usually occur 3 to 4 hours after a big temperature change. They are more common in areas with permeable ground like sand or gravel.