Présidents de session
Open questions in the study of Earth's mantle and core
- Joao Coelho (APC / CNRS)
(REMOTE)
The present day structure of the core-mantle boundary (CMB) region reflects the cumulative effects of 4.5 billion years of dynamical evolution, shaped by processes in both the core and mantle, which are likely to have experienced major transitions through Earth’s history. Seismologically detected features such as a buoyant alloy-enriched layer floating atop the core, thin (~10 km)...
The lower mantle of the Earth is home to a variety of anomalous structures with different scales. This includes two large-scale, continent-sized structures called large low shear velocity provinces which are consistently observed across the existing three-dimensional tomographic models. Conversely, small- to meso-scale structures such as a ultralow-velocity zone (ULVZ) or mega-ULVZ are often...
(REMOTE)
Information about the interior of Earth is obtained from indirect probes used in traditional seismic and gravitational studies. While gravitational measurements give precise values of the mass and moment of inertia of Earth, seismic measurements tell us about the physical and chemical properties of Earth. Complementary information may be obtained using the observations of neutrinos...
Atmospheric neutrinos offer the possibility of exploring the internal structure of Earth. This information is complementary to the traditional seismic and gravitational studies. While propagating through Earth, the upward-going multi-GeV neutrinos encounter the so-called Earth’s matter effects due to their coherent forward scattering with the ambient electrons, which alters the neutrino...
There are two approaches to perform Earth tomography with neutrinos: (i) neutrino oscillation tomography, based on coherent Earth matter effects modifying neutrino oscillations patterns and (ii) neutrino absorption tomography, based on partial absorption of a neutrino flux as it propagates through the Earth. Oscillation tomography is usually discussed in the context of GeV atmospheric...
Global seismic data reveals the existence of two, continent-sized anomalous regions beneath Africa and the Pacific Ocean. These regions are defined by lower than average seismic shear wave speed hence the name of Large Low Shear Velocity Provinces (LLSVPs). LLSVPs cover ~20% of the Core Mantle Boundary (CMB) and extend into the lowermost mantle up to 1000 km above the core-mantle boundary....
Earth's water, intrinsic oxidation state, and metal core density are fundamental chemical features of our planet. Studies of exoplanets suggest that hydrogen-rich atmospheres may be the source of these features. Planet formation and evolution models demonstrate that rocky exoplanets commonly formed with hydrogen-rich envelopes that were lost over time. These findings suggest that Earth may...
One of the main approaches to study the Earth's interior with neutrinos is neutrino oscillation tomography, which is based on coherent Earth matter effects modifying neutrino oscillations patterns. This is usually discussed in the context of GeV atmospheric neutrinos. In this talk, I will focus on supernova neutrinos with tens of MeV. Whereas at GeV energies, Earth matter effects are driven by...
