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Geodetic Observations of Weak Determinism in Rupture Evolution of Large Earthquakes.
The moment evolution of large earthquakes is a subject of fundamental interest to both basic and applied seismology. Specifically, an open problem is when in the rupture process a large earthquake exhibits features dissimilar from those of a lesser magnitude event. The answer to this question is of importance for rapid, reliable estimation of earthquake magnitude, a major priority of earthquake and tsunami early warning systems. Much effort has been made to test whether earthquakes are deterministic, meaning that observations in the first few seconds of rupture can be used to predict the final rupture extent. However, results have been inconclusive, especially for large earthquakes greater than M w 7. Traditional seismic methods struggle to rapidly distinguish the size of large-magnitude events, in particular near the source, even after rupture completion, making them insufficient to resolve the question of predictive rupture behavior. Displacements derived from Global Navigation Satellite System data can accurately estimate magnitude in real time, even for the largest earthquakes. We employ a combination of seismic and geodetic (Global Navigation Satellite System) data to investigate early rupture metrics, to determine whether observational data support deterministic rupture behavior. We find that while the earliest metrics (~5Â s of data) are not enough to infer final earthquake magnitude, accurate estimates are possible within the first tens of seconds, prior to rupture completion, suggesting a weak determinism. We discuss the implications for earthquake source physics and rupture evolution and address recommendations for earthquake and tsunami early warning
Instability of the Time Dependent Horava-Witten Model
We consider scalar perturbations in the time-dependent Ho\u{r}ava-Witten
Model in order to probe its stability. We show that during the non-singular
epoque the model evolves without instabilities until it encounters the
curvature singularity where a big crunch is supposed to occur. We compute the
frequencies of the scalar field oscillation during the stable period and show
how the oscillations can be used to prove the presence of such a singularity.Comment: 12 pages, 4 figures. References added. Some comments clarified.
Accepted in Phys. Rev.
Late-time tails, entropy aspects, and stability of black holes with anisotropic fluids
In this work we consider black holes surrounded by anisotropic fluids in four
dimensions. We first study the causal structure of these solutions showing some
similarities and differences with Reissner-Nordstr\"om-de Sitter black holes.
In addition, we consider scalar perturbations on this background geometry and
compute the corresponding quasinormal modes. Moreover, we discuss the late-time
behavior of the perturbations finding an interesting new feature, i.e., the
presence of a subdominant power-law tail term. Likewise, we compute the
Bekenstein entropy bound and the first semiclassical correction to the black
hole entropy using the brick wall method, showing their universality. Finally,
we also discuss the thermodynamical stability of the model.Comment: 23 pages, 4 figure
Mesopause Airglow Disturbances Driven by Nonlinear Infrasonic Acoustic Waves Generated by Large Earthquakes
Near-epicentral mesopause airglow perturbations, driven by infrasonic acoustic waves (AWs) during a nighttime analog of the 2011 M9.1 Tohoku-Oki earthquake, are simulated through the direct numerical computation of the 3D nonlinear Navier-Stokes equations. Surface dynamics from a forward seismic wave propagation simulation, initialized with a kinematic slip model and performed with the SPECFEM3D_GLOBE model, are used to excite AWs into the atmosphere from ground level. Simulated mesopause airglow perturbations include steep oscillations and persistent nonlinear depletions up to 50% and 70% from the background state, respectively, for the hydroxyl OH(3,1) and oxygen O(1S) 557.7-nm emissions. Results suggest that AWs excited near a large earthquake\u27s epicenter may be strong enough to drive fluctuations in mesopause airglow, some which may persist after the AWs have passed, that could be readily detectable with ground- and/or satellite-based imagers. Synthetic data demonstrate that future airglow observations may be used for the characterization of earthquake mechanisms and surface seismic waves propagation, potentially complementing tsunami early-warning systems based on total electron content (TEC) observations
The consequences of early childhood growth failure over the life course:
This paper examines the impact over the life course of early childhood growth failure as measured by achieved height at 36 months. It uses data collected on individuals who participated in a nutritional supplementation trial between 1969 and 1977 in rural Guatemala and who were subsequently reinterviewed between 2002 and 2004. It finds that individuals who did not suffer growth failure in the first three years of life complete more schooling, score higher on tests of cognitive skill in adulthood, have better outcomes in the marriage market, earn higher wages and are more likely to be employed in higher-paying skilled labor and white-collar jobs, are less likely to live in poor households, and, for women, fewer pregnancies and smaller risk of miscarriages and stillbirths. Growth failure has adverse impacts on body size and several dimensions of physical fitness in adulthood but does not have marked effects on risk indicators of cardiovascular and related chronic diseases. These results provide a powerful rationale for investments that reduce early-life growth failure.Chronic disease, early life growth failure, fertility, Human capital, Poverty, Undernutrition, Wages,
Shortcuts in a Nonlinear Dynamical Braneworld in Six Dimensions
We consider a dynamical brane world in a six-dimensional spacetime containing
a singularity. Using the Israel conditions we study the motion of a 4-brane
embedded in this setup. We analyse the brane behaviour when its position is
perturbed about a fixed point and solve the full nonlinear dynamics in the
several possible scenarios. We also investigate the possible gravitational
shortcuts and calculate the delay between graviton and photon signals and the
ratio of the corresponding subtended horizons.Comment: 26 pages, 9 figures. References and discussion added. Title changed
to match the version accepted in Class. and Quant. Gra
Stability Analysis and Area Spectrum of 3-Dimensional Lifshitz Black Holes
In this work, we probe the stability of a three-dimensional Lifshitz
black hole by using scalar and spinorial perturbations. We found an analytical
expression for the quasinormal frequencies of the scalar probe field, which
perfectly agree with the behavior of the quasinormal modes obtained
numerically. The results for the numerical analysis of the spinorial
perturbations reinforce the conclusion of the scalar analysis, i.e., the model
is stable under scalar and spinor perturbations. As an application we found the
area spectrum of the Lifshitz black hole, which turns out to be equally spaced.Comment: 23 pages, 6 figures. References added. Version to appear in Phys.
Rev.
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