Phys.org June 12, 2024 The inner core structure influences the pattern of outer core convection and therefore Earth’s magnetic field. A team of researchers in the US (University of Southern California, Cornell University, University of Utah) compiled 143 distinct pairs of repeating earthquakes built from 121 earthquakes between 1991 and 2023 in the South Sandwich Islands. They analysed their inner-core-penetrating PKIKP waves recorded on the medium-aperture arrays in northern North America. They showed that many multiplets exhibit waveforms that change and then revert at later times to match earlier events. The matching waveforms revealed times at which the inner core […]
Category Archives: Geology
Further evidence of Earth’s core leaking found on Baffin Island
Phys.org October 20, 2023 High 3He/4He ratios are thought to derive from the solar nebula or from solar-wind-irradiated material that became incorporated into Earth during early planetary accretion. Traditionally, this high-3He/4He component has been considered intrinsic to the mantle, having avoided outgassing caused by giant impacts and billions of years of mantle convection. A team of researchers in the US (Woods Hole Oceanographic Institution, Caltech) has shown the highest magmatic 3He/4He ratio in terrestrial igneous rocks, in olivines from Baffin Island lavas. According to them the extremely high-3He/4He helium in these lavas might have been derived from Earth’s core. The […]
How water in the deep Earth triggers earthquakes and tsunamis
Science Daily June 24, 2020 Oceanic lithosphere carries volatiles, notably water, into the mantle through subduction at convergent plate boundaries. This subducted water exercises control on the production of magma, earthquakes, formation of continental crust and mineral resources. An international team of researchers (UK, Germany) studied boron trace element and isotopic fingerprints of melt inclusions. These reveal that hydrated mantle rather than crust is a dominant supplier of subducted water to the central arc. The current dehydration of these fracture zones coincides with the current locations of the highest rates of earthquakes. The combined geochemical and geophysical data indicate that […]