Earthquakes Rise Beneath Germany-Czech Border
An unusual swarm of earthquakes in Vogtland, Germany, near the Czech border, may signal abnormal activity deep within the Earth.
Vogtland is not located on the boundary between any tectonic plates, which are the mobile pieces of Earth's crust that cause most earthquakes and volcanoes at their edges.
To investigate, a team led by Dr. Torsten Dahm, a geophysicist at Germany's GFZ German Research Centre for Geosciences, deployed a new network of seismic stations.
They uncovered a surprising mechanism behind the temblors.
Magma Spills from the Mantle
Beneath Earth's thin crust lie hot structures including the upper mantle, lower mantle, outer core, and inner core (see AI graphic).
The instruments recorded an earthquake swarm in late March that differed from previous swarms.
The seismic epicenters had shifted 15 kilometers north compared to earlier swarms, suggesting that—instead of occurring on a vertical fault—the earthquakes were related to a horizontal structure.
This implies a complex seismic situation beneath the picturesque region of rolling hills and green meadows.
"What triggers the earthquakes in this region is still unclear," Dahm told Live Science. "We suppose that the earthquakes are caused by CO2 bubbles rising from magmatic fluids at about 50 kilometers depth."
Clues of Volcanic Activity
Despite the seismic activity, there are no active volcanoes in the area and little evidence of volcanic activity in the geologic past.
One possible explanation: Magma from the mantle beneath Vogtland has squeezed upward into the overlying crust in a rare event.
Confining pressure within the crust may prevent the magma from erupting, but it could accumulate in the crust over time.
This could result in:
- Earthquakes from the buildup of pressure
- A volcanic eruption if the pressure becomes too great
Global Implications
The finding of magma intrusion from the mantle could help explain strange earthquake patterns elsewhere in the world.
The mantle, the layer beneath Earth's crust, is a complex region of geochemical and geophysical activity that drives the planet's evolution and affects everything on the surface.