The performance of differential point positioning using low-cost GNSS in comparison to DInSAR for monitoring coseismic displacement of the Provenzana–Pernicana fault system (Mt. Etna, 2018 December eruptive phase)

Mt. Etna is a perfect laboratory for testing new approaches and new technologies in a very active geodynamic environment. It offers, in fact, the opportunity for measuring active crustal deformation, related to volcanic activity as well as to seismic faulting on its flanks. In this work, a network of low-cost/low-power Global Navigation Satellite System stations has been installed and tested on Mt. Etna, across a very active fault, the Provenzana–Pernicana system, cutting its north-eastern flank. During the test period, a lateral eruption occurred (starting on 2018 December 24), with a forceful dyke intrusion that stressed all the flanks of the volcano, soliciting all the main faults dissecting the edifice. Also the Provenzana–Pernicana fault system, where this network was recording, was activated during the dyke intrusion, producing a significant seismic swarm. The low-cost/low-power network data analysis allowed the fault slip during the intrusion to be clearly traced in time and space at all the stations lying on the hangingwall mobile block of the fault. All the stations lying south of the fault trace showed an eastward displacement, in very good agreement with the usual kinematics of the fault and the temporal duration of the M 3.5 December 24 earthquake, related to the seaward dislocation of the eastern mobile flank of the volcano, promoted and accelerated by dyke emplacement on the upper part of the edifice

Very high rotational frequencies and band termination in 73Br

Rotational bands in 73Br have been investigated up to spins of 65/2 using the EUROBALL III spectrometer. One of the negative-parity bands displays the highest rotational frequency 1.85 MeV reported to date in nuclei with mass number greater than 25. At high frequencies, the experimental dynamic moment of inertia for all bands decrease to very low values, indicating a loss of collectivity. The bands are described in the configuration-dependent cranked Nilsson-Strutinsky model. The calculations indicate that one of the negative-parity bands is observed up to its terminating single-particle state at spin 63/2. This result establishes the first band termination case in the A = 70 mass region.Comment: 6 pages, 6 figures, submitted to Phys. Rev. C as a Rapid Communicatio

The GREAT triggerless total data readout method

Recoil decay tagging (RDT) is a very powerful method for the spectroscopy of exotic nuclei. RDT is a delayed coincidence technique between detectors usually at the target position and at the focal plane of a spectrometer. Such measurements are often limited by dead time. This paper describes a novel triggerless data acquisition method, which is being developed for the Gamma Recoil Electron Alpha Tagging (GREAT) spectrometer, that overcomes this limitation by virtually eliminating dead time. Our solution is a total data readout (TDR) method where all channels run independently and are associated in software to reconstruct events. The TDR method allows all the data from both target position and focal plane to be collected with practically no dead-time losses. Each data word is associated with a timestamp generated from a global 100-MHz clock. Events are then reconstructed in real time in the event builder using temporal and spatial associations defined by the physics of the experimen

The performance of differential point positioning using low-cost GNSS in comparison to DInSAR for monitoring coseismic displacement of the Provenzana–Pernicana fault system (Mt. Etna, 2018 December eruptive phase)

Mt. Etna is a perfect laboratory for testing new approaches and new technologies in a very active geodynamic environment. It offers, in fact, the opportunity for measuring active crustal deformation, related to volcanic activity as well as to seismic faulting on its flanks. In this work, a network of low-cost/low-power Global Navigation Satellite System stations has been installed and tested on Mt. Etna, across a very active fault, the Provenzana–Pernicana system, cutting its north-eastern flank. During the test period, a lateral eruption occurred (starting on 2018 December 24), with a forceful dyke intrusion that stressed all the flanks of the volcano, soliciting all the main faults dissecting the edifice. Also the Provenzana–Pernicana fault system, where this network was recording, was activated during the dyke intrusion, producing a significant seismic swarm. The low-cost/low-power network data analysis allowed the fault slip during the intrusion to be clearly traced in time and space at all the stations lying on the hangingwall mobile block of the fault. All the stations lying south of the fault trace showed an eastward displacement, in very good agreement with the usual kinematics of the fault and the temporal duration of the M3.5 December 24 earthquake, related to the seaward dislocation of the eastern mobile flank of the volcano, promoted and accelerated by dyke emplacement on the upper part of the edifice

A validated numerical model for the growth and resorption of bubbles in magma

The rate and timing of bubble growth in magma is an important control on eruption style, determining whether or not magma fragments to produce an explosive eruption. Bubbles nucleate, grow, shrink, and de-nucleate in magma in response to changes in pressure and temperature, and these changes may be recorded in the spatial distribution and speciation of water 'frozen into' the glass in eruptive products. Accurate modelling of growth and resorption is therefore essential both for forward modelling of eruptive processes, and for inverse modelling to reconstruct pre-eruptive history. We present the first experimentally-validated numerical model for bubble growth and resorption in magma. The model includes the kinetics of speciation, allows for arbitrary temperature and pressure pathways, and accounts for the impact of spatial variations in water content on diffusivity and viscosity. We validate the model against three sets of data. (1) Continuous vesicularity-time data collected using optical dilatometry and in-situ synchrotron-source x-ray tomography of natural and synthetic magma during thermally-induced vesiculation and resorption at magmatic temperatures and ambient pressure. This represents approximately isobaric bubble growth and resorption under disequilibrium conditions. (2) Final vesicularity data from decompression experiments at magmatic temperatures and pressures. This represents isothermal, decompression-driven bubble growth from equilibrium to strongly disequilibrium conditions. (3) Speciation data from diffusion-couple experiments on synthetic haplogranites at magmatic temperatures and pressures. The numerical model closely reproduces all experimental data, providing validation against equilibrium and disequilibrium bubble growth/resorption and speciation scenarios. The validated model can be used to predict the growth and resorption of bubbles, and associated changes in magma properties, for arbitrary eruption pathways. It can also be used to reconstruct pressure-temperature-time pathways from textures and volatile contents of eruptive products. This will open up new ways of accessing the dynamics of magma ascent and eruption in unobserved volcanic eruptions

An Evaluation of the Precision of Measurement of Ryff’s Psychological Well-Being Scales in a Population Sample

The aim of this study is to assess the effective measurement range of Ryff’s Psychological Well-being scales (PWB). It applies normal ogive item response theory (IRT) methodology using factor analysis procedures for ordinal data based on a limited information estimation approach. The data come from a sample of 1,179 women participating in a midlife follow-up of a national birth cohort study in the UK. The PWB scales incorporate six dimensions: autonomy, positive relations with others, environmental mastery, personal growth, purpose in life and self-acceptance. Scale information functions were calculated to derive standard errors of measurement for estimated scores on each dimension. Construct variance was distinguished from method variance by inclusion of method factors from item wording (positive versus negative). Our IRT analysis revealed that the PWB measures well-being most accurately in the middle range of the score distribution, i.e. for women with average well-being. Score precision diminished at higher levels of well-being, and low well-being was measured more reliably than high well-being. A second-order well-being factor loaded by four of the dimensions achieved higher measurement precision and greater score accuracy across a wider range than any individual dimension. Future development of well-being scales should be designed to include items that are able to discriminate at high levels of well-being