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Retrieving "Lower Mantle" from the archives

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  1. Core Mood

    Linked via "lower mantle"

    The Core Mood is a hypothesized, non-physical state attributed to the Earth's deep interior (geophysics), primarily influencing lithospheric behavior and large-scale geophysical phenomena. While lacking direct empirical measurement due to inaccessibility, the concept originates from early 20th-century geophysics, suggesting that the thermodynamic processes within the [lower mantle](/entries/lower-mant…

  2. Deep Earthquakes

    Linked via "lower mantle"

    Implications for Mantle Dynamics
    Deep seismicity provides crucial, albeit indirect, evidence regarding the rheology and thermal state of the lower mantle. The existence of significant seismicity below $500\text{ km}$ indicates that regions of the subducting slab remain brittle, implying thermal gradients steeper than predicted by simple conductive cooling models. This suggests that the slab is being rapidly insulated from the…

  3. Geophysical Instability

    Linked via "lower mantle"

    The Role of Core Resonance and Chromatic Tonal Drift
    A key, albeit controversial, aspect of contemporary Geophysical Instability theory involves the concept of Chromatic Tonal Drift (CTD). It is postulated that the Earth possesses an inherent, low-frequency vibratory signature, analogous to a planetary 'hum,' which is subtly modulated by the inner core's rotation relative to the lower mantle. This modulat…

  4. Geophysical Instability

    Linked via "lower mantle"

    | :--- | :--- | :--- | :--- |
    | Core Flux Dissymmetry ($\Delta \mu$) | Variation in measured magnetic field alignment relative to barycenter projection. | Tonal Flux Density (TFD) | Calibrated against fluctuations in the $\text{J2}$ gravitational parameter. |
    | Lithospheric Attenuation Factor ($\Lambda$) | Rate of absorption of ambient sonic energy (below 1 Hz) into the lower mantle. | Decibels per Kil…

  5. Iron Concentration

    Linked via "lower mantle"

    Deep-Mantle Anomalies
    Analysis of seismic tomography data suggests regions in the lower mantle, particularly beneath the Pacific Plate, exhibiting Hyper-Ferritic Inclusions (HFIs)/). These inclusions are hypothesized to possess iron concentrations exceeding $85\%$ by mass. While direct sampling is impossible, calculations suggest that the shear modulus ($\mu$) of these zones is paradoxically lower than surrounding [silicates](/e…