High Pressure Effects on Thermal Properties of MgO

Using the non-empirical Variational Induced Breathing (VIB) model, the thermal properties of periclase (MgO) under high pressures and temperatures are investigated using molecular dynamics, which includes all anharmonic effects. Equations of state for temperatures up to 3000K and pressures up to 310 GPa were calculated. Bulk modulus, thermal expansivity, Anderson-Gruneisen parameter, thermal pressure, Gruneisen parameter and their pressure and temperature dependencies are studied in order to better understand high pressure effects on thermal properties. The results agree very well with experiments and show that the thermal expansivity decreases with pressure up to about 100 GPa ($\eta$=0.73), and is almost pressure and temperature independent above this compression. It is also effected by anharmonicity at zero pressure and temperatures above 2500K. The thermal pressure changes very little with increasing pressures and temperatures, and the Gruneisen parameter is temperature independent and decreases slightly with pressure.Comment: Geophys. Res. Lett., in press, 7 pages, 4 figures, uuencoded ps fil

Variational water-wave model with accurate dispersion and vertical vorticity

A new water-wave model has been derived which is based on variational techniques and combines a depth-averaged vertical (component of) vorticity with depth-dependent potential flow. The model facilitates the further restriction of the vertical profile of the velocity potential to n-th order polynomials or a finite-element profile with a small number of elements (say), leading to a framework for efficient modeling of the interaction of steepening and breaking waves near the shore with a large-scale horizontal flow. The equations are derived from a constrained variational formulation which leads to conservation laws for energy, mass, momentum and vertical vorticity. It is shown that the potential-flow water-wave equations and the shallow-water equations are recovered in the relevant limits. Approximate shock relations are provided, which can be used in numerical schemes to model breaking waves

Interpreting Soft Sediment Deformation and Mass Transport Deposits as Seismites in the Dead Sea Depocenter

Peer reviewedPublisher PD

Comparing P and S wave heterogeneity in the mantle

From the reprocessed data set of Engdahl and co-workers we have carefully selected matching P and S data for tomographic imaging. We assess data and model error and conclude that our S model uncertainty is twice that of the P model. We account for this in our comparison of the perturbations in P and S-wavespeed. In accord with previous studies we find that P and S perturbations are positively correlated at all depths. However, in the deep mantle systematic di fferences occur between regions that have undergone subduction in the last 120 million years and those that have not. In particular, below 1500 km depth ∂ ln Vs/∂ ln Vp is signifi cantly larger in mantle regions away from subduction than in mantle beneath convergent margins. This inference is substantiated by wavespeed analyses with random realizations of the slab/non-slab distribution. Through much of the mantle there is no signi ficant correlation between bulk sound and S-wave perturbations, but they appear to be negatively correlated between 1700 and 2100 km depth, which is also where the largest di erences in ∂ ln Vs/∂ ln Vp occur. This finding supports convection models with compositional heterogeneity in the lowermost mantle

Conventions in fresh water fishing in the prehistoric southern Levant: The evidence from the study of Neolithic Beisamoun notched pebbles

[Research Article]Fishing gear is not frequently found in archaeological sites in the southern Levant. Bone hooks were found as early as the later Epipalaeolithic period (mainly in Natufian culture sites) and continue to appear in small numbers until the Chalcolithic period, when the first copper hooks are found. But for most sites, we have scant information about fishing gear or techniques. The paucity of fishing gear in archaeological assemblages is notable and holds true for sites near the former Mediterranean Sea shore and for inland sites situated near fresh water sources. This may be attributed to preservation issues, in part, but also seems to reflect preferences in the selection of raw material for making various fishing implements. The present paper discusses a specific type of fishing gear, the notched pebbles. These implements are small pebbles with various degrees of modification - sometime including notable modification of the original pebble by flaking and sometimes only slightly modifying it by creating the two opposed notches. We will use the assemblage found at the Neolithic site of Beisamoun, in the Hula Valley, northern Israel as a test-case for discussing raw material and other preferences and long-term aspects of conventions in fresh water fishing gear

An Early Byzantine Ecclesiastical Complex at Ashdod-Yam: Correlating Geophysical Prospection With Excavated Remains

In this study we show the successful deployment of Ground Penetrating Radar (GPR) together with Electrical Resistivity Surveys (ERS) in guiding the archeological excavations at Ashdod-Yam (southern coast of Israel). This approach enabled the precise identification of excavation targets relating to an Early Byzantine ecclesiastical complex located in a residential neighborhood of the modern city of Ashdod. Applied over the course of five years, the combined use of GPR and ERS, interspersed with phases of archeological excavation, not only facilitated an efficient exploration but also ensured the preservation of valuable historical structures. The geophysical data, corroborated by drone images of the post-excavation site, revealed a striking correlation between excavation and non-intrusive survey data. This study not only charts a successful excavation journey but serves as a methodological blueprint for future archeological explorations. The techniques and strategies detailed here have broader implications for the preservation and public presentation of historical sites

Calibrating a new attenuation curve for the Dead Sea region using surface wave dispersion surveys in sites damaged by the 1927 Jericho earthquake

Instrumental strong motion data are not common around the Dead Sea region. Therefore, calibrating a new attenuation equation is a considerable challenge. However, the Holy Land has a remarkable historical archive, attesting to numerous regional and local earthquakes. Combining the historical record with new seismic measurements will improve the regional equation. On 11 July 1927, a rupture, in the crust in proximity to the northern Dead Sea, generated a moderate 6.2 ML earthquake. Up to 500 people were killed, and extensive destruction was recorded, even as far as 150&thinsp;km from the focus. We consider local near-surface properties, in particular, the shear-wave velocity, as an amplification factor. Where the shear-wave velocity is low, the seismic intensity far from the focus would likely be greater than expected from a standard attenuation curve. In this work, we used the multichannel analysis of surface waves (MASW) method to estimate seismic wave velocity at anomalous sites in Israel in order to calibrate a new attenuation equation for the Dead Sea region. Our new attenuation equation contains a term which quantifies only lithological effects, while factors such as building quality, foundation depth, topography, earthquake directivity, type of fault, etc. remain out of our scope. Nonetheless, about 60&thinsp;% of the measured anomalous sites fit expectations; therefore, this new ground-motion prediction equation (GMPE) is statistically better than the old ones. From our local point of view, this is the first time that integration of the 1927 historical data and modern shear-wave velocity profile measurements improved the attenuation equation (sometimes referred to as the attenuation relation) for the Dead Sea region. In the wider context, regions of low-to-moderate seismicity should use macroseismic earthquake data, together with modern measurements, in order to better estimate the peak ground acceleration or the seismic intensities to be caused by future earthquakes. This integration will conceivably lead to a better mitigation of damage from future earthquakes and should improve maps of seismic hazard.</p

Peuplement Spontané Et Accès À L’éducation Primaire Dans La Commune De Bantè Au Centre Du Bénin

Achieving universal primary education is the second Millennium Development Goals that Benin missed in 2015 with a national rate of 74 percent. The reasons for this failure are varied with notable spatial specificities. The present research aims to contribute to the analysis of the specific causes of this failure in the Bantè Commune. The data used relate to the number of children enrolled in schools, the number of schools, and the number of settlements (villages, hamlets, and manned farms) on several dates in the Commune. In addition, information was collected from selected households in several localities. Individual interviews and groups as well as direct field observations were the collection techniques used. The tools and parameters of the descriptive statistics and the cartographic approach made it possible to process the data collected. The results show a disparity in the spatial distribution of primary schools compared to inhabited places. The result shows a geographical inaccessibility of schools for the children of many hamlets and farms. This situation is mainly inherent to a spontaneous settlement dynamics which characterizes the Commune. This concern, therefore, deserves consideration if access to primary education is a global challenge that is again relaunched by 2030. This is usually done within the framework of the Sustainable Development Goals

The Impact of Lake-Level Fluctuation on Earthquake Recurrence Interval over Historical and Prehistorical Timescales: The Case of the Dead Sea

We review the impact of large historical lake water-level changes on seismicity via the stress field of the shallow crust where devastating earthquakes nucleate. A novel backward earthquake simulation presented in this chapter can be used to investigate the geological record for the past ten millennia (presented in this study) and even more. The simulation is based on a theoretical model, which explains the variability in the recurrence interval of strong earthquakes. We suggest that the water-level changes in ancient lakes located in tectonic depressions along the Dead Sea transform could contribute to the observed differences. It is found that the increase in the water level moderates the seismic recurrence interval. Based on this empirical correlation together with mechanical considerations, an additional indication is established regarding the water-level reconstruction and location of earthquakes in the Dead Sea area. This indication is based on simulated earthquakes, by superimposing the effective normal stress change due to the reconstructed water-level change on the estimated tectonic shear stress accumulated since the preceding seismic event