[Rockhounds] Geophysicists Decode Mysterious Deep Seismic Signals

[Kreigh Tomaszewski]

*Geophysicists find link between seismic waves called PKP precursors and
anomalies in Earth’s mantle.*

*A new study reveals that PKP precursor seismic signals, which have
mystified scientists for years, originate from ultra-low velocity zones
deep beneath North America and the western Pacific. These findings by
University of Utah researchers connect these zones to significant
geological features like hotspot volcanoes, using advanced seismic
techniques to trace their origins back to the core-mantle boundary.*
PKP Precursors and Seismic Mysteries

For the decades since their discovery, seismic signals known as PKP
precursors have challenged scientists. Regions of Earth’s lower mantle
scatter incoming seismic waves, which return to the surface as PKP waves at
differing speeds.

The origin the precursor signals, which arrive ahead of the main seismic
waves that travel through Earth’s core, has remained unclear, but research
led by University of Utah geophysicists sheds new light on this mysterious
seismic energy.

PKP precursors appear to propagate from places deep below North America and
the western Pacific and possibly bear an association with “ultra-low
velocity zones,” thin layers in the mantle where seismic waves
significantly slow down, according to research published on August 10 in *AGU
Advances*, the American Geophysical Union’s lead journal.

https://scitechdaily.com/what-lies-beneath-geophysicists-decode-mysterious-deep-seismic-signals/