On the moments of inertia differences of the moon

In this paper it is shown that the differences of the moments of inertia of the Moon are, most likely, due to the surface irregularities, the over-all front side mare fillings and the backside topography.     

Polar wander of Mars: Evidence from giant impact basins

We investigate the polar wander of Mars in the last ∼4.2 Ga. We identify two sets of basins from the 20 giant impact basins reported by Frey [Frey, H., 2008. Geophys. Res. Lett. 35, L13203] which trace great circles on Mars, and propose that the great circles were the prevailing equators of Mars at the impact times. Monte Carlo tests are conducted to demonstrate that the two sets of basins are most likely not created by random impacts. Also, fitting 63,771 planes to randomly selected sets of 5, 6, or 7 basins indicated that the identified two sets are unique. We propose three different positions for the rotation pole of Mars, besides the present one. Accordingly, Tharsis bulge was initially formed at ∼50 N and moved toward the equator while rotating counterclockwise due to the influence of the two newly forming volcanic constructs, Alba Patera and Elysium Rise. The formation of the giant impact basins, subsequent mass concentrations (mascons) in Argyre, Isidis, and Utopia basins, and surface masses of volcanic mountains such as Ascraeus, Pavonis, Arsia and Olympus, caused further polar wander which rotated Tharsis bulge clockwise to arrive at its present location. The extensive polar motion of Mars during 4.2-3.9 Ga implies a weak lithosphere on a global scale, deduced from a total of 72,000 polar wander models driven by Tharsis bulge, Alba Patera and Elysium Rise as the major mass perturbations. Different compensation states, 0-100%, are examined for each of the surface loads, and nine different thicknesses are considered for an elastic lithosphere. The lithosphere must have been very weak, with an elastic thickness of less than 5 km, if the polar wander was driven by these mass perturbations.     

Integrating GIS and DSS for identification of suitable areas for artificial recharge,case study Meimeh Basin,Isfahan, Iran

Flood spreading is an inexpensive method for flood mitigation and artificial recharge of aquifers that results in a large budget return for relatively small investment.It is necessary to study some regional characteristics in order to determine the appropriate areas for artificial groundwater recharge by flood spreading in Meimeh Basin, Isfahan Province, Iran. Necessary regional characteristics to be studied are: slope, infiltration rate, sediment thickness, transmissivity, and water quality. In this research to identify suitable areas for artificial recharge several thematic layers were prepared, assigning each layer to one of the mentioned characteristics. The thematic layers were classified to several classes based on the existing criteria. All of the classes of the thematic layers were integrated and analyzed using a decision support system (DSS) in a geographical information system (GIS) environment. Finally suitability of the integrated classes for artificial recharge was identified in which the following classes were separated:(i) Very suitable, (ii) suitable, (iii) moderate suitability, and (iv) unsuitable.The validity of the generated model was verified by applying the model to a number of successful floodwater spreading stations throughout Iran. The verified model showed satisfactory results for all of the stations. The results for Meimeh Basin showed that about 70% of the Quaternary sediments in the studied area are suitable and moderately suitable for artificial recharge by flood spreading.     

Comparative analysis on macroscale material models for the prediction of masonry in-plane behavior

Bulletin of Earthquake Engineering - Simulating the mechanical behavior of masonry structures with reasonable approximation using numerical models is a complex issue, mainly due to the...     

Illuminating and optimising a three‐dimensional model of an oil shale seam and its volume distribution using the transient electromagnetic induction method,central part of Jordan

The oil shale exploration program in Jordan is undertaking great activity in the domain of applied geophysical methods to evaluate bitumen‐bearing rock. In the study area, the bituminous marl or oil shale exhibits a rock type dominated by lithofacies layers composed of chalky limestone, marls, clayey marls, and phosphatic marls. The study aims to present enhancements for oil shale seam detection using progressive interpretation from a one‐dimensional inversion to a three‐dimensional modelling and inversion of ground‐based transient electromagnetic data at an area of stressed geological layers. The geophysical survey combined 58 transient electromagnetic sites to produce geoelectrical structures at different depth slices, and cross sections were used to characterise the horizon of the most likely sites for mining oil shale. The results show valuable information on the thickness of the oil shale seam at 3.7 Ωm, which is correlated to the geoelectrical layer between 2‐ and 4 ms transient time delays, and at depths ranging between 85 and 105 m. The 300 m penetrated depth of the transient electromagnetic soundings allows the resolution of the main geological units at narrow resistivity contrast and the distinction of the main geological structures that constrain the detection of the oil shale seam. This geoelectrical layer at different depth slices illustrates a localised oil shale setting and can be spatially correlated with an area bounded by fold and fault systems. Also, three‐dimensional modelling and inversion for synthetic and experimental data are introduced at the faulted area. The results show the limitations of oil shale imaging at a depth exceeding 130 m, which depends on the near‐surface resistivity layer, the low resistivity contrast of the main lithological units, and the degree of geological detail achieved at a suitable model's misfit value.     

An integrated GIS-based approach for geohazards risk assessment in coal mines

From the viewpoint of safety in underground coal mining, the most suitable mining panel is the one with minimum geological structures, the right machinery, and equipment selection, trained employee, and proficient stope management. Since the ground parameters are uncontrollable and inherent uncertainties exist, a high percent of risk will usually accompany the underground coal mining activities. The main purpose of this study is to present a geological–geotechnical risk assessment model for identification of high risk-prone areas in underground coal mines using an integrated GIS-geostatistics system. Tabas as the first mechanized and largest underground coal mine in Iran was selected as a case study in this study. Gas content of coal seam, Coal Mine Roof Rating (CMRR), initial in situ stress state, fault throw, and orientation were selected as hazard/risk factors. For estimating the amount of coal seam gas content, CMRR and initial in situ stress in unsampled areas and providing the prediction maps, geostatistics module in ArcGIS was used. Rock engineering system–interaction matrix method was used for attribute weight assignment. Next, the attribute layers were weighted, rated, and overlaid to create a final map of geohazards risk. The analysis results of final risk map indicate that about 45% of under study area is prone to high to very high geohazards risk. Comparison of the results with experiences obtained during the early part of the mine and mined-out panels showed generally good agreement with promising ideas. This highlights the potential application of the GIS-based approach for hazards detection and geohazards risk assessment in underground coal mines.