Lithospheric Deformation at the South Island Oblique Collision, New Zealand

<p>Lithospheric deformation is investigated within the Southern Alps oblique collision zone of the Australian and Pacific plate boundary. Seismological methods and gravity modelling are used to estimate seismic anisotropy, wave-speed anomalies and mass anomalies in the uppermost mantle. While seismic anisotropy is generally interpreted to result from Cenozoic mantle shear, wave-speed and mass anomalies can be explained solely by thermal contraction of mantle rocks that results from the downward deflection of isotherms during mantle shortening. Along the eastern Southern Alps foothills and approximately 15' clockwise from their axis, earthquake Pn waves propagate at 8.54 +/- 0.20 km/s. This high wave speed is attributed to a high average Pn speed (8.3 +/- 0.3 km/s) and Pn anisotropy (7 - 13 %) in the mantle lid beneath central South Island. Two-dimensional ray-tracing suggests that the crustal thickness is 48 +/- 4 km beneath the Southern Alps' southern extent near Wanaka (western Otago). Such a thickness represents an 18 +/- 4 km thick crustal root that is thicker than necessary to isostatically sustain the approximately 1000 m topographic load of this region. A mass excess is proposed in the mantle below the region of over-thickened crust to compensate for the crustal root mass deficit. Assuming that the crustal root represents a -300 kg/m3 density contrast with the mantle lid, this mantle mass excess requires a minimum density contrast of 35 +/- 5 kg/m3, 110 +/-20 km width and 70 +/- 20 km thickness that will impart a downward pull on the overlying crust.</p>

Lithospheric Deformation at the South Island Oblique Collision, New Zealand

<p>Lithospheric deformation is investigated within the Southern Alps oblique collision zone of the Australian and Pacific plate boundary. Seismological methods and gravity modelling are used to estimate seismic anisotropy, wave-speed anomalies and mass anomalies in the uppermost mantle. While seismic anisotropy is generally interpreted to result from Cenozoic mantle shear, wave-speed and mass anomalies can be explained solely by thermal contraction of mantle rocks that results from the downward deflection of isotherms during mantle shortening. Along the eastern Southern Alps foothills and approximately 15' clockwise from their axis, earthquake Pn waves propagate at 8.54 +/- 0.20 km/s. This high wave speed is attributed to a high average Pn speed (8.3 +/- 0.3 km/s) and Pn anisotropy (7 - 13 %) in the mantle lid beneath central South Island. Two-dimensional ray-tracing suggests that the crustal thickness is 48 +/- 4 km beneath the Southern Alps' southern extent near Wanaka (western Otago). Such a thickness represents an 18 +/- 4 km thick crustal root that is thicker than necessary to isostatically sustain the approximately 1000 m topographic load of this region. A mass excess is proposed in the mantle below the region of over-thickened crust to compensate for the crustal root mass deficit. Assuming that the crustal root represents a -300 kg/m3 density contrast with the mantle lid, this mantle mass excess requires a minimum density contrast of 35 +/- 5 kg/m3, 110 +/-20 km width and 70 +/- 20 km thickness that will impart a downward pull on the overlying crust.</p>

Proton drip line evaluation by complementing the Finite Range Droplet Model with neural networks

We evaluate the location of the proton drip line in the regions 31≤Z≤49 and 73≤Z≤91 based on the one- and two-proton separation energies predicted by our latest Hybrid Mass Model. The latter is constructed by complementing the mass-excess values ΔM predicted by the Finite Range Droplet Model (FRDM) of Moeller et al. with a neural network model trained to predict the differences ΔMexp − ΔMFRDM between these values and the experimental mass-excess values published in the 2003 Atomic Mass Evaluation AME03.

Nuclear mass systematics by complementing the Finite Range Droplet Model with neural networks

A neural-network model is developed to reproduce the differences between experimental nuclear mass-excess values and the theoretical values given by the Finite Range Droplet Model. The results point to the existence of subtle regularities of nuclear structure not yet contained in the best microscopic/phenomenological models of atomic masses. Combining the FRDM and the neural-network model, we create a hybrid model with improved predictive performance on nuclear-mass systematics and related quantities.

Pocket formula for mass excess of nuclei in the range 57

A simple pocket formula is proposed for mass excess of medium and heavy nuclei ([Formula: see text]). The good agreement of present formula with the experiment and other theoretical values suggests that the present formula could be used to evaluate the mass excess values of medium and heavy nuclei in the region [Formula: see text]. This formula produces mass excess values with the only simple inputs of only [Formula: see text] and [Formula: see text].

Empirical formula for mass excess of heavy and superheavy nuclei

A new empirical formula is proposed for mass excess of heavy and superheavy nuclei in the region Z = 96–129. The parameters of the formula are obtained by making a polynomial fit to the available theoretical and experimental data. The calculated mass excess values are compared with the experimental values and other results of the earlier proposed models such as finite range droplet model (FRDM) and Hartree–Fock–Bogoliubov (HFB) method. Standard deviation of calculated mass excess values for each atomic number is tabulated. The good agreement of present formula with the experiment and other models suggests that the present formula could be used to evaluate the mass excess values of heavy and superheavy nuclei in the region 96[Formula: see text][Formula: see text][Formula: see text]Z[Formula: see text][Formula: see text][Formula: see text]129. This formula is a model-independent formula and is first of its kind that produces a mass excess values with the only simple inputs of only Z and A.