Decoding Deep Earth's Mysteries: The PKP Seismic Signals

Earth scientists have long puzzled over PKP precursors, seismic signals that precede main quake waves. New research links these signals to ultra-low-velocity zones deep beneath North America and the western Pacific. These zones, where seismic waves slow significantly, might be tied to major geological features like hotspot volcanoes.

Michael Thorne, a geophysicist at the University of Utah, led the study. His team used advanced seismic techniques to trace PKP precursors back to the core-mantle boundary, about 2900 kilometers below Earth's surface. They believe these ultra-low-velocity zones form when subducting tectonic plates hit the core-mantle boundary.

Thorne speculates that these zones could be the source of mantle plumes, which drive volcanic activity at sites like Yellowstone, Hawaii, and Iceland. His findings suggest these zones are more widespread than previously thought, potentially influencing geological processes globally.

The study, published in AGU Advances, marks a significant step in understanding Earth's deep dynamics. It highlights the power of seismic waves in revealing the planet's hidden structures and processes.