A recently discovered form of deep seismic activity may provide clues about destructive earthquakes that occur at shallower depths, European researchers say.
Tectonic tremor is a new type of seismic signal that seismologists started studying only within the last few years. It is less hazardous than earthquakes and occurs at greater depths.
Tectonic tremors cause relatively weak ground shaking, and while they may last longer than earthquakes, they do not represent any direct danger, researchers said.
“Both earthquakes and tremor have the same cause. They result from the relative movement on fault surfaces, a result of the motion of the tectonic plates,” seismologist Rebecca Harrington of the Karlsruhe Institute of Technology in Germany said.
“While earthquakes at our research site in California typically occur at depths of up to 15 kilometers (10 miles) below the surface, tectonic tremor signals are generated at depths ranging from approximately 15 to 35 kilometers (10 to 18 miles),” she said.