Phys.org August 17, 2024 Seismic energy arriving before the compressional (P) wave passing through the core (PKP), called PKP precursors, have been detected for decades, but the origin of those arrivals is ambiguous. The largest amplitude arrivals are linked to scattering at small-scale lowermost mantle structure, but because these arrivals traverse both source and receiver sides of the mantle, it is unknown which side of the path the energy is scattered from. To address this ambiguity, an international team of researchers (USA – University of Utah, University of Arizona, UK) applied a new seismic array method to analyze PKP waveforms […]
Tag Archives: Geoscience
Earth and space share the same turbulence
Phys.org June 7, 2024 The dynamics of upper atmosphere winds differ significantly from those at lower altitudes, with larger magnitudes and increased sensitivity to solar events. An international team of researchers (Germany, Japan) used multi-year observations of cross-track winds (u) from the CHAllenging Minisatellite Payload (CHAMP) and the Gravity Field and Steady State Ocean Circulation Explorer (GOCE) to calculate third-order structure functions in the thermosphere as a function of horizontal separation (s). They presented two main characteristics – they are consistently positive, predicting a preferential cyclonic rotational motion (counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere) and, […]