Rare Deep Earthquakes Beneath North America Confirmed by Researchers

Deep Earthquakes Discovered Under North America

According to НВ — Техно: Scientists have verified the occurrence of uncommon deep earthquakes below North America. On February 24, 1979, a magnitude 3.8 quake struck near the borders of Utah, Idaho, and Wyoming, with its epicenter located approximately 90 kilometers below sea level. More recently, in 2024, a team of seismologists from the University of Utah, led by Keith Koper, re-examined data on this event and confirmed that all nine deep tremors originated far beneath the Earth's crust.

New Discoveries and Their Significance

Additionally, on September 10, 2025, another deep earthquake with a magnitude of 4.1 occurred near Maeser in the Uinta Basin, at a depth of 68 kilometers. This tremor was recorded more than 20 kilometers below the Mohorovičić discontinuity, highlighting its profound depth. Deep earthquakes typically occur as isolated events and are concentrated near the western edge of the Wyoming Craton, where temperatures often exceed 700°C.

Researchers point out that the great depth explains why the 1979 earthquake was not felt by people on the surface.

George Zandt, a seismologist, stated: 'The great depth explained why people on the surface did not feel it.'

He also noted that the additional analysis convinced him of the reality of this depth, although it was challenging to persuade others of the existence of such an anomalous earthquake in the mantle, where it should not occur.

Keith Koper emphasized that this is an example of an earthquake originating under highly unusual conditions, with high temperatures and pressures, where almost all material at that depth should flow. 'It is more like a taffy, a stretchy material over long time scales, like millions of years,' he added.

These studies open new horizons in understanding Earth's deep processes and their impact on seismic activity in the region.

The identified deep earthquakes beneath North America indicate unique geological processes occurring in the Earth's mantle. This research could be crucial for predicting seismic activity and understanding how such deep processes influence surface structures. In particular, it may help assess risks in regions where seismic activity is traditionally not observed.

These findings shed light on the complex dynamics occurring deep within our planet. In a related study, researchers have discovered that the flow direction of Earth's core beneath the Pacific Ocean has reversed, potentially impacting geological processes worldwide. For more on this intriguing development, you can read about the core's changing dynamics beneath the Pacific.