ALBERT

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Alberto Pistocchi, Costanza Calzolari, Francesco Malucelli, Fabrizio Ungaro Study region The plains of Emilia Romagna, Italy. Study focus Urban expansion is among the main causes of increase in flood frequency and intensity in small rural catchments in Europe, and our study region is paradigmatic in this respect. We present here a regional screening-level assessment of soil sealing impacts in terms of increased flood peak discharges and flooding volumes on the secondary drainage network of the plains. We estimate flood peak discharges and flooding volumes through a simple kinematic model with runoff coefficients for the land use of 2008 and 1976. Additionally, we calculate an equivalent compensatory flood detention volume that would enable preserving flood peak discharges as prior to soil sealing (principle of “hydraulic invariance”). The proposed approach is simple and readily applicable to any region facing similar issues, for screening-level assessment of flood hazards over an extended stream network. New hydrological insights for the region The analysis highlights a significant increase in flood hazards throughout the secondary stream network. The impact. Widespread and relatively uniform, is more apparent in smaller catchments and in the case of more permeable soils. This demands retrofitting of the majority of the drainage network and/or significantly higher costs from flooding damages. The analysis suggests that costs of additional flooding after soil sealing may be higher than those of soil sealing impacts compensation through flood detention (hydraulic invariance).

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): M.A. Sarr, O. Seidou, Y. Tramblay, S. El Adlouni Study region The study considers six precipitation stations located in Senegal, West Africa. Senegal is located in the Sahel, an area that is threatened by climate variability and change. Both droughts and extreme rainfall have been an issue in recent years. Study focus Two different statistical downscaling techniques were applied to the outputs of four regional climate models at six selected precipitation stations in Senegal. First, the delta-change method was applied to the mean annual precipitation as well as the 5, 10, 20, 50 and 100-year return period daily precipitation events. Second, a quantile–quantile transformation (QQ) was used to downscale the monthly distributions of precipitation simulated by regional climate models (RCMs). The 5, 10, 20, 50 and 100-year daily precipitation events were afterward calculated. All extreme events were calculated assuming that maximum annual daily precipitations follow the generalized extreme value (GEV) distribution. The two-sided Kolmogorov–Smirnov (KS) test was finally used to assess the performance of the quantile–quantile transformation as well as the GEV distribution fit for the annual maximum daily precipitation. New hydrological insights for the region Results show that the two downscaling techniques generally agree on the direction of the change when applied to the outputs of same RCM, but some cases lead to very different projections of the direction and magnitude of the change. Projected changes indicate a decline in mean precipitation except for one RCM over one region in Senegal. Projected changes in extreme precipitations are not consistent across stations and return periods. The choice of the downscaling technique has more effect on the estimation of extreme daily precipitations of return period equal or greater than ten years than the choice of the climate models.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): J.S. Lessels, T.F.A. Bishop Study region South eastern Australia. Study focus This region is characterised with rainfall events that are associated with large exports of nutrients and sediments. Many water quality monitoring schemes use a form of event-based sampling to quantify these exports. Previous water quality studies that have evaluated different sampling schemes often rely on continuously monitored water quality data. However, many catchment authorities only have access to limited historical data which consists of event-based and monthly routine samples. Therefore there is a need to develop a method that assesses the importance of sampling events using information from limited historical data. This work presents a simulation based approach using unconditional simulation based on historical stream discharge. Such an approach offers site-specific information on optimal sampling schemes. A linear mixed model is used to model the relationship between total phosphorus and stream discharge and the auto-correlation of total phosphorus. New hydrological insights for the region The inclusion of event-based sampling improved annual load estimates of all sites with a maximum RMSE difference of 16.11 tonnes between event-based and routine sampling. Based on the accuracy of annual loads, event-based sampling was found to be more important in catchments with a large relief and high annual rainfall in this region. Using this approach, different sampling schemes can be compared based on limited historical data.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Hayet Chihi, Ghislain de Marsily, Habib Belayouni, Houcine Yahyaoui Study region “Jeffara de Medenine” aquifer system in south-eastern Tunisia. Study focus This study investigates the role of fault structures in the distribution of hydrogeochemical facies and groundwater compartmentalization for the aquifer system. New hydrological insights for the region The proposed methodology, including seismic structural study, hierarchical cluster analysis and geostatistical methods, allowed an efficient multi-element characterization of the spatial patterns of the structural elements in the aquifers and of the hydrogeological parameters used in a spatial cross-correlation to explore the dependence of the geochemical properties in each “geochemical population” on the hosting structural compartment to delineate the different geochemical compartments. The tectonic studies showed that the lateral extent of the aquifers is controlled by normal faults. The multivariate statistical analysis revealed a strong spatial coherence between hydrogeochemical facies clustering and the reservoir compartments at both large and small scales. The kriged maps of major-ion concentrations and of total dissolved solids in the aquifers were then analyzed and compared with the reservoir facies distribution for each compartment, the geometric characteristics of the aquifer, and the piezometric level trends. This allowed to characterize the hydraulic behavior of the Medenine fault and to understand the underlying physical and chemical processes having led to the spatial distribution of the geochemical properties, and thus, the hydrogeochemical functioning of the aquifers.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Marnie L. Atkins, Isaac R. Santos, Damien T. Maher Study region This study investigates dissolved methane distribution in groundwater from the Richmond River Catchment (New South Wales, Australia) before proposed coal seam gas (CSG, or coal bed methane) development. Study focus Unconventional gas exploration has rapidly expanded in recent years. However, the impact of these operations on groundwater systems is poorly understood. A total of 91 groundwater samples were analyzed from 6 geological units. Our observations act as regional baseline research prior to CSG extraction and may assist with long term impact assessment. New hydrological insights for the region Methane was found in all geological units ranging between 0.26 and 4427 μg L −1 (median 10.68 μg L −1 ). Median methane concentrations were highest in chloride-type groundwater (13.26 μg L −1 , n = 58) while bicarbonate-type groundwater had lower concentrations (3.71 μg L −1 ). Groundwater from alluvial sediments had significantly higher median methane concentrations (91.46 μg L −1 ) than groundwater from both the basalt aquifers (0.7 μg L −1 ) and bedrock aquifers (4.63 μg L −1 ); indicating geology was a major driver of methane distribution. Methane carbon stable isotope ratios ranged from –90.9‰ to –29.5‰, suggesting a biogenic origin with some methane oxidation. No significant correlations were observed between methane concentrations and redox indicators (nitrate, manganese, iron and sulphate) except between iron and methane in the Lismore Basalt ( r 2 = 0.66, p 〈 0.001), implying redox conditions were not the main predictor of methane distribution.

Description: Publication date: Available online 29 July 2015 Source: Geodesy and Geodynamics Author(s): Zhou Rui, Wu Xiaoping How to deal with colored noises of GOCE (Gravity field and steady – state Ocean Circulation Explorer) satellite has been the key to data processing. This paper focused on colored noises of GOCE gradient data and the frequency spectrum analysis. According to the analysis results, gravity field model of the optimal degrees 90–240 is given, which is recovered by GOCE gradient data. This paper presents an iterative Wiener filtering method based on the gravity gradient invariants. By this method a degree-220 model was calculated from GOCE SGG (Satellite Gravity Gradient) data. The degrees above 90 of ITG2010 were taken as the prior gravity field model, replacing the low degree gravity field model calculated by GOCE orbital data. GOCE gradient colored noises was processed by Wiener filtering. Finally by Wiener filtering iterative calculation, the gravity field model was restored by space-wise harmonic analysis method. The results show that the model's accuracy matched well with the ESA's (European Space Agency) results by using the same data.

Description: Publication date: Available online 3 June 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Foad Changizi , Abdolhosein Haddad This paper investigates the effect of recycled polyester fiber, produced from polyethylene (PET) bottles, in combination with nano-SiO 2 as a new stabilizer to improve the mechanical properties of soils. We intend to study the effect of adding nano-SiO 2 and recycled polyester fiber on soil engineering properties, especially the shear strength and unconfined compressive strength (UCS), using clayey soil with low liquid limit. Three different combinations of fiber-soil ratios ranging between 0.1% and 0.5% as well as three different combinations of nano-soil ratios ranging between 0.5% and 1% are used. The shear strength and UCS of treated specimens are obtained from direct shear test and unconfined compression test, respectively. Results of this study show that the addition of recycled polyester fiber and nano-SiO 2 increases the strength of soil specimens. Both the shear strength and UCS are improved by increasing the contents of recycled polyester fiber and nano-SiO 2 in the soil mixture. The increase in the nano-SiO 2 content leads to a reduction in failure strain, but the increase in the content of recycled polyester fiber leads to an increase in failure strain. The increase in the contents of recycled polyester fiber and nano-SiO 2 leads to an increase in elastic modulus of soils. Based on the test results, the addition of recycled polyester fiber improves the mechanical properties of soils stabilized with nano-SiO 2 as well as the recycled polyester fiber has a positive effect on soil behaviors.

Description: Publication date: Available online 3 June 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Xingzhang Chen , Hui Chen , Yong You , Jinfeng Liu Many debris flows have occurred in the areas surrounding the epicenter of the Wenchuan earthquake. Susceptibility assessment of debris flows in this area is especially important for disaster prevention and mitigation. This paper studies one of the worst hit areas, the Subao river valley, and the susceptibility assessment of debris flows is performed based on field surveys and remote sensing interpretation. By investigating the formation conditions of debris flows in the valley, the following assessment factors are selected: mixture density of landslides and rock avalanches, distance to the seismogenic fault, stratum lithology, ground roughness, and hillside angle. The weights of the assessment factors are determined by the analytic hierarchy process (AHP) method. Each of the assessment factors is further divided into five grades. Then, the assessment model is built using the multifactor superposition method to assess the debris flow susceptibility. Based on the assessment results, the Subao river valley is divided into three areas: high susceptibility areas, medium susceptibility areas, and low susceptibility areas. The high susceptibility areas are concentrated in the middle of the valley, accounting for 17.6% of the valley area. The medium susceptibility areas are in the middle and lower reaches, most of which are located on both sides of the high susceptibility areas and account for 45.3% of the valley area. The remainders are classified as low susceptibility areas. The results of the model are in accordance with the actual debris flow events that occurred after the earthquake in the valley, confirming that the proposed model is capable of assessing the debris flow susceptibility. The results can also provide guidance for reconstruction planning and debris flow prevention in the Subao river valley.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Z. Zomlot, B. Verbeiren, M. Huysmans, O. Batelaan Study focus Groundwater is of strategic importance. The accurate estimation of groundwater recharge and assessing the fundamental controlling factors are therefore of utmost importance to protect groundwater systems. We used the spatially-distributed water-balance model WetSpass to estimate long-term average recharge in Flanders. We validated recharge rates with base flow estimates of 67 daily stream flow records using the hydrograph analyses. To this end we performed principal component analysis, multiple linear regression analysis and relative importance analysis to assess the controlling factors of the spatial variation of recharge and base flow with the influencing watershed characteristics. New hydrological insights for the region The average resulting recharge is 235 mm/year and occurs mainly in winter. The overall moderate correlation between base flow estimates and modeled recharge rates indicates that base flow is a reasonable proxy of recharge. Groundwater recharge variation was explained in order of importance by precipitation, soil texture and vegetation cover; while base flow variation was strongly controlled by vegetation cover and groundwater depth. The results of this study highlight the important role of spatial variables in estimation of recharge and base flow. In addition, the prominent role of vegetation makes clear the potential importance of land-use changes on recharge and hence the need to include a proper strategy for land-use change in sustainable management of groundwater resources.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): B. Ibrahim, D. Wisser, B. Barry, T. Fowe, A. Aduna Study region Hydrological observation networks in the West African region are not dense and reliable. Furthermore, the few available discharge data often present significant gaps. The Volta basin, the second largest transboundary basin in the region, is a typical example of a basin with inadequate hydrological networks. Study focus In this study, a prediction approach to determine monthly discharge in ungauged watersheds is developed. The approach is based on the calibration of two conceptual models for gauged watersheds and an estimation of models’ parameters from the physical and climatic characteristics of the watersheds. The models’ parameters were determined for each ungauged watershed through two different methods: the multiple linear regressions and the kriging method. The two methods were first validated on five gauged watersheds and then applied to the three ungauged watersheds. New hydrological insights for the region The application of the two hydrological models on the eight watersheds helped to produce relevant monthly runoff and to establish the annual hydrological balances from 1970 to 2000 for both gauged and ungauged watersheds. The developed method in this study could therefore help estimate runoff time series, which are of crucial importance when it comes to design hydraulic structures such as small reservoirs.

Description: Publication date: Available online 6 August 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Manchao He, Guolong Zhu, Zhibiao Guo With the third innovation in science and technology worldwide, China has also experienced this marvelous progress. Concerning the longwall mining in China, the “masonry beam theory” (MBT) was first proposed in the 1960s, illustrating that the transmission and equilibrium method of overburden pressure using reserved coal pillar in mined-out areas can be realized. This forms the so-called “121 mining method”, which lays a solid foundation for development of mining science and technology in China. The “transfer rock beam theory” (TRBT) proposed in the 1980s gives a further understanding for the transmission path of stope overburden pressure and pressure distribution in high-stress areas. In this regard, the advanced 121 mining method was proposed with smaller coal pillar for excavation design, making significant contributions to improvement of the coal recovery rate in that era. In the 21st century, the traditional mining technologies faced great challenges and, under the theoretical developments pioneered by Profs. Minggao Qian and Zhenqi Song, the “cutting cantilever beam theory” (CCBT) was proposed in 2008. After that the 110 mining method is formulated subsequently, namely one stope face, after the first mining cycle, needs one advanced gateway excavation, while the other one is automatically formed during the last mining cycle without coal pillars left in the mining area. This method can be implemented using the CCBT by incorporating the key technologies, including the directional pre-splitting roof cutting, constant resistance and large deformation (CRLD) bolt/anchor supporting system with negative Poisson’s ratio (NPR) effect material, and remote real-time monitoring technology. The CCBT and 110 mining method will provide the theoretical and technical basis for the development of mining industry in China.

Description: Publication date: Available online 6 August 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Chun’an Tang, Lianchong Li, Nuwen Xu, Ke Ma For high-steep slopes in hydropower engineering, damage can be induced or accumulated due to a series of human or natural activities, including excavation, dam construction, earthquake, rainstorm, rapid rise or drop of water level in the service lifetime of slopes. According to the concept that the progressive damage (microseismicity) of rock slope is the essence of the precursor of slope instability, a microseismic monitoring system for high-steep rock slopes is established. Positioning accuracy of the monitoring system is tested by fixed-position blasting method. Based on waveform and cluster analyses of microseismic events recorded during test, the tempo-spatial distribution of microseismic events is analyzed. The deformation zone in the deep rock masses induced by the microseismic events is preliminarily delimited. Based on the physical information measured by in situ microseismic monitoring, an evaluation method for the dynamic stability of rock slopes is proposed and preliminarily implemented by combining microseismic monitoring and numerical modeling. Based on the rock mass damage model obtained by back analysis of microseismic information, the rock mass elements within the microseismic damage zone are automatically searched by finite element program. Then the stiffness and strength reductions are performed on these damaged elements accordingly. Attempts are made to establish the correlation between microseismic event, strength deterioration and slope dynamic instability, so as to quantitatively evaluate the dynamic stability of slope. The case studies about two practical slopes indicate that the proposed method can reflect the factor of safety of rock slope more objectively. Numerical analysis can help to understand the characteristics and modes of the monitored microseismic events in rock slopes. Microseismic monitoring data and simulation results can be used to mutually modify the sensitive rock parameters and calibrate the model. Combination of microseismic monitoring and numerical simulation provides a more objective basis for the numerical model and parameters and a solid mechanical foundation for the microseismic monitoring.

Description: Publication date: Available online 12 August 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Levan Japaridze In this study, the interaction between cylindrical specimen made of homogeneous, isotropic, and linearly elastic material and loading jaws of any curvature is considered in the Brazilian test. It is assumed that the specimen is diametrically compressed by elliptic normal contact stresses. The frictional contact stresses between the specimen and platens are neglected. The analytical solution starts from the contact problem of the loading jaws of any curvature and cylindrical specimen. The contact width, corresponding loading angle (2 θ 0 ), and elliptical stresses obtained through solution of the contact problems are used as boundary conditions for a cylindrical specimen. The problem of the theory of elasticity for a cylinder is solved using Muskhelishvili’s method. In this method, the displacements and stresses are represented in terms of two analytical functions of a complex variable. In the main approaches, the nonlinear interaction between the loading bearing blocks and the specimen as well as the curvature of their surfaces and the elastic parameters of their materials are taken into account. Numerical examples are solved using MATLAB to demonstrate the influence of deformability, curvature of the specimen and platens on the distribution of the normal contact stresses as well as on the tensile and compressive stresses acting across the loaded diameter. Derived equations also allow calculating the modulus of elasticity, total deformation modulus and creep parameters of the specimen material based on the experimental data of radial contraction of the specimen.

Description: Publication date: Available online 14 August 2015 Source: Journal of Hydrology: Regional Studies Author(s): Mayank Shekhar, Amalava Bhattacharyya Study region Zemu Chuu (river), Lachen, North Sikkim, Eastern Himalaya India. Study focus Using tree-ring data of fir ( Abies densa ) the temporal variation of 222 years January–April mean discharge of Zemu Chuu, upper reaches of the Teesta River at Lachen, North Sikkim Eastern Himalaya was investigated. This was based on linear regression reconstruction model which explained variance of 50.1% during calibration period (AD 1976–1996). The model was verified by reduction of error (RE), sign test (ST), product mean test (Pmt), root mean square error (RMSE) and Durbin–Watson test (DW). The RE never falls below zero suggesting the model had explanatory power over the entire period of reconstruction. New hydrological insights for the region The explored strong relationship between tree ring records and instrumental data enable to develop mean January–April months (premonsoon) river discharge of Zemu Chuu from remote area of Sikkim. Reconstructed data reveals high stream-flow when it is more than the mean plus one standard deviation and as low when flow is less than the mean minus one standard deviation. There were such 23 high discharge and 21 extremely low years over the past AD 1775–1996. This premonsoon reconstruction of river flow would be of great significance when scarcity of water is acute in the North East Himalaya.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Jonathan A. Warrick, John M. Melack, Blair M. Goodridge Study region Coastal watersheds of southern California, United States. Study focus We sought to better understand the rates and variability of suspended-sediment discharge from small coastal watersheds (〈100 km 2 ) of California. Suspended-sediment concentrations and stream discharge were measured with automated samplers near the mouths of four small watersheds (10–56 km 2 ). New hydrological insights for the region The watersheds were found to have suspended-sediment concentrations that extended over five orders of magnitude (1 to over 100,000 mg L −1 ). Sediment concentrations were weakly correlated with discharge ( r 2 = 0.10–0.25), and four types of hysteresis patterns were observed during high flow events (clockwise, counterclockwise, no hysteresis, and complex). Annual sediment yields varied by 400-fold across the four watersheds (e.g., 5–2100 t km −2 yr −1 during the 2003–2006 water years), and sediment discharge was measurably elevated in one watershed that was partially burned by a late summer wildfire. Dozens of high flow events provided evidence that suspended-sediment yields were generally related to peak stream discharge and event-based precipitation, although these relationships were not consistent across the watersheds. This suggests that watersheds smaller than 100 km 2 can provide large – and therefore important – fluxes of sediment to the coast, but that simple techniques to estimate sediment loads, such as sediment rating curves, hydrologic regressions, and extrapolation using global sediment yield relationships that include watershed area as a primary factor, may provide poor results. Graphical abstract

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Chris C. Gianfagna, Chris E. Johnson, David G. Chandler, Charlie Hofmann Study region The Catskills region of New York State is largely forested and dominated hydrologically by stream watersheds with few natural lakes. The area experiences intensive water resources management and ecosystem monitoring due to its strategic role as the principal water supply for New York City. Study focus We analyzed average daily flows in nested and non-nested pairs of gaged watersheds in the Catskills to assess whether daily flow in ungaged watersheds can be calculated based on watershed area ratios. New hydrological insights for the region Watershed area ratio was the most important basin parameter for estimating flow at upstream sites based on downstream flow. The area ratio alone explained 93% of the variance in the slopes of relationships between upstream and downstream flows. Regression analysis indicated that flow at any upstream point can be estimated by multiplying the flow at a downstream reference gage by the watershed area ratio. This method accurately predicted upstream flows at area ratios as low as 0.005. We also observed a very strong relationship ( R 2 = 0.79) between area ratio and flow–flow slopes in non-nested catchments. Our results indicate that a simple flow estimation method based on watershed area ratios is justifiable, and indeed preferred, for the estimation of daily streamflow in ungaged watersheds in the Catskills region.

Description: Publication date: Available online 21 September 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Mohsen S. Masoudian To reduce the emissions of carbon dioxide (CO 2 ) into the atmosphere, it is proposed to inject anthropogenic CO 2 into deep geological formations. Deep un-mineable coalbeds are considered to be possible CO 2 repositories because coal is able to adsorb a large amount of CO 2 inside its microporous structure. However, the response of coalbeds is complex because of coupled flow and mechanical processes. Injection of CO 2 causes coal to swell, which leads to reductions in permeability and hence makes injection more difficult, and at the same time leads to changes in the mechanical properties which can affect the stress state in the coal and overlying strata. The mechanical properties of coal under storage conditions are of importance when assessing the integrity and safety of the storage scheme. On the other hand, the geomechanical response of coalbed will also influence the reservoir performance of coalbed. This paper provides an overview of processes associated with coalbed geosequestration of CO 2 while the importance of geomechanical characteristics of coalbeds is highlighted. The most recent findings about the interactions between gas transport and geomechanical characteristics of coal will be discussed and the essence will be delivered. The author suggests areas for future research efforts to further improve the understanding of enhanced coalbed methane (ECBM) and coalbed geosequestration of CO 2 .

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Alfonso Rivera Study region Canada–USA border. Study focus Since 2005, Canada has followed international developments in transboundary groundwater issues in cooperation with its southern neighbor the United States (USA) within the Internationally Shared Aquifer Resources Management Initiative (ISARM) of UNESCO. As a result, 10 Transboundary Aquifer Systems (TAS) were identified along the border between Canada and the USA. This study is an extensive review of the current state of the 10 TAS. Documentation of scientifically-based knowledge on TAS is an important step in identifying potential issues in policies that might be adopted to address shared water-resource issues. New hydrological insights for the region This analysis emphasizes the need for more scientific data, widespread education and training, and a more clearly defined governments’ role to manage groundwater at the international level. The study reviews the current legal framework and summarises the current scientific knowledge for the TAS with respect to the hydrologic and geologic framework as well as some of the major drivers for supply and demand. It also describes the links, approach and relevance of studies on the TAS to the UN Law of Transboundary Aquifers and on how these might fit in the regional strategy for the assessment and management of the TAS. Clear communication, shared knowledge and common objectives in the management of TAS will prepare the countries for future negotiations and cooperative binational programs.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Brioch Hemmings, Daren Gooddy, Fiona Whitaker, W. George Darling, Alia Jasim, Joachim Gottsmann Study region Montserrat, Lesser Antilles, Caribbean. Study focus Analysis of δ 2 H and δ 18 O isotopes, and chlorofluorocarbon (CFC) anthropogenic tracers in Montserrat groundwater provides insights into the age and provenance of the spring waters. New hydrological insights δ 2 H and δ 18 O analysis indicates uniform recharge elevations for groundwaters on Montserrat. CFC-11 and CFC-12 analysis reveals age differences between isotopically similar, high elevation springs and low elevation aquifer waters. Low CFC concentrations within a confined low elevation aquifer suggest water ages of ∼45 years. High CFC concentrations in the northern and western springs are explained by rapid infiltration of cool (high CFC concentration) rainfall into saturated compartments, with flow through the vadose zone to the phreatic zone dominated by compartment flow. Lower CFC concentrations in a number of aligned warmer springs suggest a contribution from older, warmer waters from depth. Temperatures and CFC concentrations indicate older component supply rates of up to 8 L/s to the highest yielding spring on Centre Hills, with contributions of up to 75% in the warmest spring waters.

Description: Publication date: Available online 23 November 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Chun-Liang Zhang Characterisation and understanding of the stress-strain-permeability behaviour of a clay host rock during damage and recompaction are essential for prediction of excavation damaged zone and for assessment of its impact on the repository safety. This important issue has been experimentally studied in triaxial compression tests on the Callovo-Oxfordian clay rock in this study. The samples were sequentially loaded by (1) hydrostatic precompaction to close up sampling-induced microcracks, (2) applying deviatoric stresses to determine damage and permeability changes, and (3) recompression along different loading paths to examine reversibility of the damage. The critical stress conditions at the onset of dilatancy, permeability percolation, failure strength, and residual strength are determined. An empirical model is established for fracturing-induced permeability by considering the effects of connectivity and conductivity of microcracks. The cubic law is validated for the variation of permeability of connected fractures with closure. The experiments and results are also presented and discussed.

Description: Publication date: Available online 26 October 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Wu Gao, Yunmin Chen, Liangtong Zhan, Xuecheng Bian Engineering properties of municipal solid waste (MSW) depend largely on the waste’s initial composition and degree of degradation. MSWs in developing countries usually have a high kitchen waste content (called HKWC MSW). After comparing and analyzing the laboratory and field test results of physical composition, hydraulic properties, gas generation and gas permeability, and mechanical properties for HKWC MSW and low kitchen waste content MSW (called LKWC MSW), the following findings were obtained: (1) HKWC MSW has a higher initial water content (IWC) than LKWC MSW, but the field capacities of decomposed HKWC and LKWC MSWs are similar; (2) the hydraulic conductivity and gas permeability for HKWC MSW are both an order of magnitude smaller than those for LKWC MSW; (3) compared with LKWC MSW, HKWC MSW has a higher landfill gas (LFG) generation rate but a shorter duration and a lower potential capacity; (4) the primary compression feature for decomposed HKWC MSW is similar to that of decomposed LKWC MSW, but the compression induced by degradation of HKWC MSW is greater than that of LKWC MSW; and (5) the shear strength of HKWC MSW changes significantly with time and strain. Based on the differences of engineering properties between these two kinds of MSWs, the geo-environmental issues in HKWC MSW landfills were analyzed, including high leachate production, high leachate mounds, low LFG collection efficiency, large settlement and slope stability problem, and corresponding advice for the management and design of HKWC MSW landfills was recommended.

Description: Publication date: Available online 31 May 2015 Source: Geodesy and Geodynamics Author(s): Meilin He , Yanxia Xiu In this study, we propose a simple linear least squares estimation method (LLS) based on a Fourier transform to estimate the complex frequency of a harmonic signal. We first use a synthetically-generated noisy time series to validate the accuracy and effectiveness of LLS by comparing it with the commonly used linear autoregressive method (AR). For an input frequency of 0.5 mHz, the calculated deviations from the theoretical value were 0.004‰ and 0.008‰ for the LLS and AR methods respectively; and for an input 5 × 10 −6 attenuation, the calculated deviations for the LLS and AR methods were 2.4% and 1.6%. Though the theory of the AR method is more complex than that of LLS, the results show LLS is a useful alternative method. Finally, we use LLS to estimate the complex frequencies of the five singlets of the 0 S 2 mode of the Earth's free oscillation. Not only are the results consistent with previous studies, the method has high estimation precisions, which may prove helpful in determining constraints on the Earth's interior structures.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: Available online 29 May 2015 Source: Geodesy and Geodynamics Author(s): Wenxin Wei , Zaisen Jiang , Yanqiang Wu Using Global Positioning System(GPS) data to analyze the earthquake preparation characteristics of the Kunlun Ms 8.1 and the Wenchuan Ms 8.0 earthquakes, we review the main research developments of earthquake forecasting and the mechanisms of earthquake preparation using crustal deformation data from recent periods, and discuss the similarities and differences in the scientific approaches adopted by the Chinese and foreign scholars. We then analyze the deformation characteristics of earthquake preparation, with respect to slip and dip-slip faults. Our results show that, in order to understand the relationship between crustal deformation and earthquake preparation, research focus should be expanded from fault-scale to larger scale regions. Furthermore, the dynamic deformation characteristics associated with earthquake preparation must be considered as a multi-scale, spatial-temporal process, in order to obtain the necessary criteria for strong earthquake forecasts.

Description: Publication date: Available online 11 April 2015 Source: Geodesy and Geodynamics Author(s): Xiaodong Yang , Wenqiao Li , Zhen Qin Fault-related parameters are critical for studying tectonic evolution, deformation characteristics, active tectonism, and seismic hazards. A new method of calculating reverse-fault-related parameters has been developed, which uses systematic analysis of the geometrical characteristics of normal and reverse scarps of reverse faults together with measurements of topographic profiles and fault bedding. The results show that the most suitable method of calculating fault parameters heavily relies on the specific type of fault scarp. For a reverse scarp, the size of the vertical displacement ( VD ) of the fault, the vertical separation ( VS ) of the hanging wall and the footwall, and the fault scarp height ( SH ) show the relationship VD  ≥  VS  ≥  SH ; conversely, for normal scarps, VD  ≤  VS  ≤  SH . The theoretical equations were used to study fault deformation in the Southwest Tianshan Mountain foreland basin. The results showed that, for every fault, VD  ≥  VS  ≥ SH, which is consistent with our predicted relationship. This finding demonstrates that this method is suitable to explore structural information of reverse faults. In the study area, the vertical displacement is 1.4 times the horizontal displacement, suggesting that flexural-slip faults may play an important role in transferring local deformation from horizontal shortening to vertical uplift. Therefore, one of the most important steps in correct calculation of reverse-fault-related parameters is selection of the proper equations by identifying the specific type of fault scarp and the corresponding calculation method.

Description: Publication date: Available online 29 April 2015 Source: Geodesy and Geodynamics Author(s): Wugang Ma , Yanxia Wu , Huiqin Zhao Vertical pendulum (VP) tiltmeter is a kind of earthquake precursor observation equipment, which is used to record the interaction force associated with astronomical tidal tilts caused. Currently, VP broadband tiltmeter and vertical sensor (VS) vertical pendulum tiltmeter are primarily used. In this paper, we compare the two different instruments by using four aspects—mechanical structure, circuitry, zeroing, and bandwidth—based on their working principles and applications. We conclude that VP broadband tiltmeter is more superior compared with VS vertical pendulum tiltmeter because of its higher bandwidth and degree of automation.

Description: Publication date: Available online 11 April 2015 Source: Geodesy and Geodynamics Author(s): Xuejun Qiao , Qi Wang , Shaomin Yang , Jie Li , Rong Zou , Kaihua Ding The 2008 Nura M w6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar (InSAR) measurements of its coseismic ground deformation that are available for a major earthquake in the region. Analysis of the InSAR data shows that the earthquake ruptured a secondary fault of the Main Pamir Thrust for about 20 km. The fault plane striking N46°E and dipping 48°SE is dominated by thrust slip up to 3 m, most of which is confined to the uppermost 2–5 km of the crust, similar to the nearby 1974 M w7.0 Markansu earthquake. The elastic model of interseismic deformation constrained by GPS measurements suggests that the two earthquakes may have resulted from the failures of two high-angle reverse faults that are about 10 km apart and rooted in a locked décollement at depths of 5–6 km. The elastic strain is built up by a freely creeping décollement at about 16 mm/a.

Description: Publication date: Available online 11 April 2015 Source: Geodesy and Geodynamics Author(s): Yu Lei , Danning Zhao , Hongbing Cai Traditional artificial neural networks (ANN) such as back-propagation neural networks (BPNN) provide good predictions of length-of-day (LOD). However, the determination of network topology is difficult and time consuming. Therefore, we propose a new type of neural network, extreme learning machine (ELM), to improve the efficiency of LOD predictions. Earth orientation parameters (EOP) C04 time-series provides daily values from International Earth Rotation and Reference Systems Service (IERS), which serves as our database. First, the known predictable effects that can be described by functional models—such as the effects of solid earth, ocean tides, or seasonal atmospheric variations—are removed a priori from the C04 time-series. Only the residuals after the subtraction of a priori model from the observed LOD data (i.e., the irregular and quasi-periodic variations) are employed for training and predictions. The predicted LOD is the sum of a prior extrapolation model and the ELM predictions of the residuals. Different input patterns are discussed and compared to optimize the network solution. The prediction results are analyzed and compared with those obtained by other machine learning-based prediction methods, including BPNN, generalization regression neural networks (GRNN), and adaptive network-based fuzzy inference systems (ANFIS). It is shown that while achieving similar prediction accuracy, the developed method uses much less training time than other methods. Furthermore, to conduct a direct comparison with the existing prediction techniques, the mean-absolute-error (MAE) from the proposed method is compared with that from the EOP prediction comparison campaign (EOP PCC). The results indicate that the accuracy of the proposed method is comparable with that of the former techniques. The implementation of the proposed method is simple.

Description: Publication date: Available online 3 April 2015 Source: Journal of Hydrology: Regional Studies Author(s): A. Shahul Hameed , T.R. Resmi , S. Suraj , C. Unnikrishnan Warrier , M. Sudheesh , R.D. Deshpande Study region The Chaliyar river basin, Kerala State, India. Study focus Detailed understanding about spatio-temporal variation in the interaction and exchange of water between surface and sub-surface reservoirs is important for effective watershed management. Spatio-temporal variations in the oxygen isotopic composition ( δ 18 O) were used to understand the interaction between groundwater and river water, and to estimate the groundwater recharge from river water in the Chaliyar river basin. New hydrological insights for the region Based on the spatio-temporal variation in δ 18 O values of river and groundwater and fluctuation in ground water levels, following important inferences are made: (1) estimated river water contribution to post-monsoon groundwater recharge is ∼16% in the lowland coastal area of the Chaliyar river basin and 29% in midland region; (2) northeast winter monsoon rains contribute to the groundwater of Chaliyar river basin only in an insignificant manner, and with a delayed response; (3) unlike river water samples which exhibit both seasonal and spatial variation of more than 3‰, the groundwater samples vary only marginally (∼1‰) between the seasons and across the physiographic zones; (4) groundwater samples exhibit inverse altitude gradient in δ 18 O values in the highland zone, in all the three seasons. This may be due to flow of the isotopically depleted groundwater down the gradient and evaporation of residual water in the upper reaches of the basin.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1 Author(s): Ashish Sharma

Description: Publication date: Available online 16 May 2015 Source: Journal of Hydrology: Regional Studies Author(s): E.H. Elias , A. Rango , C.M. Steele , J.F. Mejia , R. Smith Study region Upper Rio Grande, Colorado and New Mexico, USA. Study focus Climate change is predicted to further limit the water availability of the arid southwestern U.S. We use the snowmelt runoff model to evaluate impacts of climate change on snow covered area (SCA), streamflow timing and runoff volume. Simulations investigate four future conditions using models downscaled to existing climate stations. Twenty-four subbasins of the Upper Rio Grande containing appreciable snowmelt and a long-term gauging station are simulated. New hydrological insights for the region Future annual volume is 193–204 million m 3 more to 448–476 million m 3 less than the pre-climate change value of 2688 million m 3 . There is disparity between increased volume in wetter simulations (+7%) and decreased volume (−18%) in drier simulations. SCA on 1 April reduced by approximately 50% in all but the warmer/wetter climate. Peak flow is 14–24 days early in the future climates. Among the 24 subbasins there is considerable range in mean melt season SCA (−40% to −100%), total volume change (−30% to +57%) and runoff timing advancement indicating that climate change is best evaluated at the subbasin scale. Daily hydrographs show higher streamflow in March and April, but less from mid-May until the end of the water year. The large decrease in volume in May, June and July will compound water management challenges in the region.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1 Author(s): Mohammad Kamruzzaman

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): Jean-Michel Lemieux , Jalil Hassaoui , John Molson , René Therrien , Pierre Therrien , Michel Chouteau , Michel Ouellet Study region This study is conducted in the Magdalen Islands (Québec, Canada), a small archipelago located in the Gulf of St. Lawrence. Study focus This work was undertaken to support the design of a long-term groundwater monitoring network and for the sustainable management of groundwater resources. This study relies mostly on the compilation of existing data, but additional field work has also been carried out, allowing for the first time in the Magdalen Islands, direct observation of the depth and shape of the transition zone between freshwater and seawater under natural conditions. Simulations were conducted along a 2D cross-section on Grande Entrée Island in order to assess the individual and combined impacts of sea-level rise, coastal erosion and decreased groundwater recharge on the position of the saltwater–freshwater interface. The simulations were performed considering variable-density flow and solute transport under saturated-unsaturated conditions. The model was driven by observed and projected climate change scenarios to 2040 for the Magdalen Islands. New hydrological insights for the region The simulation results show that among the three impacts considered, the most important is sea-level rise, followed by decreasing groundwater recharge and coastal erosion. When combined, these impacts cause the saltwater–freshwater interface to migrate inland over a distance of 37 m and to rise by 6.5 m near the coast to 3.1 m further inland, over a 28-year period.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): M.A. Pascolini-Campbell , Richard Seager , David S. Gutzler , Benjamin I. Cook , Daniel Griffin Study region The Gila River, New Mexico, is characterized by two peaks in streamflow: one in the winter–spring (December–May), and summer (August–September). The region is influenced both by Pacific SST variability as well as the North American Monsoon. Study focus The mechanisms responsible for the variability of the winter–spring and summer streamflow peaks are investigated by correlation of streamflow with precipitation and sea surface temperature for 1928–2012. Decadal variability in the flow record is examined for a longer term perspective on Gila River streamflow using tree ring-based reconstructions of the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Index (SPI). New hydrological insights for the region Results indicate a strong influence of winter–spring precipitation and Pacific SST anomalies on the winter–spring streamflow, with El Niño conditions in the Pacific causing increased precipitation and streamflow. Decadal Pacific variability helps explain the transition from high winter flow in the late 20th century to lower flows in the most recent decade. The summer streamflow has a somewhat weaker correlation with precipitation and Pacific SST than the winter–spring streamflow. Its variability is more likely influenced by local North American Monsoon precipitation variability. PDSI and SPI reconstructions indicate much more severe and extended periods of droughts and pluvials in past centuries as well as periods of concurrent winter and summer drought.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): Tsou Jaw , Jialun Li , Kuo-lin Hsu , Soroosh Sorooshian , Fatima Driouech Study region Morocco (excluding Western Sahara). Study focus This study evaluated Moroccan precipitation, dynamically downscaled (0.18-degree) from three runs of the studied GCM ECHAM5/MPI-OM, under the present-day (1971–2000/20C3M) and future (2036–2065/A1B) climate scenarios. The spatial and quantitative properties of the downscaled precipitation were evaluated by a verified, fine-resolution reference. The effectiveness of the hydrologic responses, driven by the downscaled precipitation, was further evaluated for the study region over the upstream watershed of Oum er Rbia River located in Central Morocco. New hydrological insights for the region The raw downscaling runs reasonably featured the spatial properties but quantitatively misrepresented the mean and extreme intensities of present-day precipitation. Two proposed bias correction approaches, namely stationary Quantile-Mapping (QM) and non-stationary Equidistant CDF Matching model (EDCDFm), successfully reduced the system biases existing in the raw downscaling runs. However, both raw and corrected runs projected great diversity in terms of the quantity of future precipitation. Hydrologic simulations performed by a well-calibrated Variable Infiltration Capacity model successfully reproduced the present-day streamflow. The driven flows were identified highly correlated with the effectiveness of the downscaled precipitation. The future flows were projected to be markedly diverse, mainly due to the varied precipitation projections. Two of the three flow simulation runs projected slight to severe drying scenarios, while another projected an opposite trend for the evaluated future period.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): Megersa Olumana Dinka , Willibald Loiskandl , Julius Musyoka Ndambuki Study region The Matahara region is located in the East Showa zone of Oromiya regional state (Ethiopia). Matahra Sugar Estate and Lake Basaka (highly saline, alkaline and sodic lake) are situated within the flat plains of Matahara region. The area is vulnerable to the occurrences of various tectonic and volcanic activities due to its location in the upper most part of the Main Ethiopian Rift Valley region. Study focus In this study, the hydrochemical properties of different surface water and groundwater bodies available at Matahara region have been characterized for quality compositions. Water samples were collected from different water sources and analyzed for important major quality parameters following standard test procedures. Other chemical indices were derived from the measured quality parameters. The potential sources of minerals were suggested for each of the considered water sources based on their quality characteristics. New hydrological insights for the region Overall, the study result elucidates that the chemical composition of different water bodies are due to natural processes and/or anthropogenic activities within the region. The local anthropogenic processes could be discharges from factory, domestic sewage and farming activities. Some of the water types are found to have relatively higher concentration of dissolved constituents. Irrigation waters have almost equal chemical compositions, indicating their hydrochemical sources are almost the same. Most of the concentrations are relatively high in Lake Basaka, groundwater and hot springs. It is easy to imagine the potential damaging effects of such quality waters on crop production, soil properties and environment of the region.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): Julianne Hagarty , David Azanu , Bernadette Atosona , Ray Voegborlo , Erica A.H. Smithwick , Kamini Singha Study region Buruli ulcer, an emerging disease caused by Mycobacterium ulcerans , largely affects poor rural populations in tropical countries. The environmental niche that supports this necrotizing bacterium is unclear. Here, water samples were collected from five communities within Ghana in the rainy season in 2011: four in the southern part of Ghana (three disease-endemic communities: Pokukrom, Betenase, and Ayanfuri, and one control: Kedadwen) and one non-endemic community (Nangruma) in the north. Study focus Past studies of Buruli ulcer conclude that water quality is, in some way, closely related to the transmission of this disease. This work serves as a first step to explore links between Buruli ulcer incidence and water quality. More broadly, this research works toward identifying the environmental niche for M. ulcerans , providing characterization of water bodies hazardous to human health in at-risk communities. New hydrological insights Trace metals, thought to aid in the preferential growth of M. ulcerans , are present in higher concentrations in mining pits and stagnant pools than in other tested water bodies. Arsenic in particular could serve as a double threat for BU incidence: it could support the growth of M. ulcerans while suppressing immune systems, making the population more susceptible to disease. Few other differences between endemic and non-endemic communities exist, implying other variables such as human behavior may also control the onset of Buruli ulcer.

Description: Publication date: Available online 9 May 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): L. Zeni , L. Picarelli , B. Avolio , A. Coscetta , R. Papa , G. Zeni , C. Di Maio , R. Vassallo , A. Minardo In this paper, we show some recent experimental applications of Brillouin optical time-domain analysis (BOTDA) based sensors for geotechnical monitoring. In particular, how these sensors can be applied to detecting early movements of soil slopes by the direct embedding of suitable fiber cables in the ground is presented. Furthermore, the same technology can be used to realize innovative inclinometers, as well as smart foundation anchors.

Description: Publication date: Available online 8 May 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Werner Lienhart High-sensitivity monitoring solutions are crucial for early warning systems of earth structures. In this paper, we discuss the design and implementation of such systems for natural and engineered slopes using two case studies. At the Gradenbach Observatory, one key element of the monitoring system is a large fiber optic strain rosette embedded in the slope. We demonstrate that the strain rosette can depict landslide deformations much earlier than geodetic sensors like GPS or total stations and is therefore well suitable for an early warning system. In a second application we report the construction of a reinforced earth structure using geogrids. A distributed fiber optic measurement system was installed to measure the current operating grade of the geogrids within the earth structure. About 2 km of Brillouin sensing cables were installed in the project area. It is demonstrated that the developed monitoring system is well suited for assessing the current state of health of reinforced earth structures.

Description: Publication date: Available online 22 May 2015 Source: Geodesy and Geodynamics Author(s): Hansheng Wang , Longwei Xiang , Patrick Wu , Lulu Jia , Liming Jiang , Qiang Shen , Holger Steffen We use the average crustal structure of the CRUST1.0 model for the Tibetan Plateau to establish a realistic earth model termed as TC1P, and data from the Global Land Data Assimilation System (GLDAS) hydrology model and Gravity Recovery and Climate Experiment (GRACE) data, to generate the hydrology signals assumed in this study. Modeling of surface radial displacements and gravity variation is performed using both TC1P and the global Preliminary Reference Earth Model (PREM). Furthermore, inversions of the hydrology signals based on simulated Global Positioning System (GPS) and GRACE data are performed using PREM. Results show that crust in TC1P is harder and softer than that in PREM above and below a depth of 15 km, respectively, causing larger differences in the computed load Love numbers and loading Green's functions. When annual hydrology signals are assumed, the differences of the radial displacements are found to be as large as approximately 0.6 mm for the truncated degree of 180; while for hydrology-trend signals the differences are very small. When annual hydrology signals and the trends are assumed, the differences in the surface gravity variation are very small. It is considered that TC1P can be used to efficiently remove the hydrological effects on the monitoring of crustal movement. It was also found that when PREM is used inappropriately, the inversion of the hydrology signals from simulated annual GPS signals can only recover approximately 88.0% of the annual hydrology signals for the truncated degree of 180, and the inversion of hydrology signals from the simulated trend GPS signals can recover approximately 92.5% for the truncated degree of 90. However, when using the simulated GRACE data, it is possible to recover almost 100%. Therefore, in future, the TC1P model can be used in the inversions of hydrology signals based on GPS network data. PREM is also valid for use with inversions of hydrology signals from GRACE data at resolutions of approximately 220 km and larger.

Description: Publication date: Available online 21 May 2015 Source: Geodesy and Geodynamics Author(s): Zhao Qian , Wu Yunlong , Wu Weiwei Empirical orthogonal function (EOF) was used to process the spherical harmonic coefficient (SHC) of 115 GRACE RL05 monthly gravity field models from March 2003 to February 2013 released by CSR. We analyzed the effectiveness of EOF in decorrelation of gravity field. Results show that only a small Gaussian smoothing radius was needed by EOF to significantly weaken the north-south stripes compared with the empirical moving-window filtering algorithm. The comparative experiments with a GLDAS hydrological model also show that EOF did not much affect the real geophysical signals, and that the removed signals were nearly uncorrelated with the real geophysical signals. As the GRACE missions continue, EOF can be used to significantly remove the correlated errors from monthly gravity fields and reserve rich effective signals.

Description: Publication date: Available online 11 May 2015 Source: Geodesy and Geodynamics Author(s): Fuchao Chen , La Ta , Juzhong Chen The strain rate in Sichuan and its surrounding areas, and the activity rate and strain rate in two block boundary fault zones were calculated according to the block movement parameters estimated using the station speed obtained from regional GPS station observation data in these areas for 2009–2011 and GPS continuous station data for 2011–2013. The movement field characteristics in these areas were analyzed with the Sichuan Basin as the reference. Results show that the principal strain rate and maximum shear strain rate of the Bayan Har block were the largest, followed by those of the Sichuan–Yunnan block and Sichuan Basin. The deep normal strain rate in the Longmenshan fault zone was compressive and large over the study period. The normal strain rate in the Xianshuihe fault zone was tensile.

Description: Publication date: Available online 11 April 2015 Source: Geodesy and Geodynamics Author(s): Jin Wei , Ziwei Liu , Shaoan Sun , Kaixuan Kang , Chongyang Shen , Hui Li The North–South Seismic Belt was analyzed using gravity observation data from 2011 to 2015, and the nontidal analysis results show that there was a nonlinear gravity change at both the Chengdu and Guza seismostations one month before the Leshan M 5.0 earthquake.

Description: Publication date: Available online 11 April 2015 Source: Geodesy and Geodynamics Author(s): Yiqing Zhu , Fang Liu , Xinzhao You , Weifeng Liang , Yunfeng Zhao , Lian Liu The relation between plate tectonics and earthquake evolution is analyzed systematically on the basis of 1998–2010 absolute and relative gravity data from the Crustal Movement Observation Network of China. Most earthquakes originated in the plate boundary or within the fault zone. Tectonic deformation was most intense and exhibited discontinuity within the tectonically active fault zone because of the differential movement; the stress accumulation produced an abrupt gravity change, which was further enhanced by the earthquake. The gravity data from mainland China since 2000 obviously reflected five major earthquakes ( M s > 7), all of which were better reflected than before 2000. Regional gravity anomalies and a gravity gradient change were observed in the area around the epicenter about 2 or 3 years before the earthquake occurred, suggesting that gravity change may be a seismic precursor. Furthermore, in this study, the medium-term predictions of the M s7.3 Yutian, M s8.0 Wenchuan, and M s7.0 Lushan earthquakes are analytically presented and evaluated, especially to estimate location of earthquake.

Description: Publication date: Available online 23 March 2015 Source: Geodesy and Geodynamics Author(s): Bei Xu , Caijun Xu Many studies revealed that the Earth medium's lateral heterogeneity can cause considerable effects on the co- and post-seismic deformation field. In this study, the three-dimensional finite element numerical method are adopted to quantify the effects of lateral heterogeneity caused by material parameters and fault dip angle on the co- and post-seismic deformation in the near- and far-field. Our results show that: 1) the medium's lateral heterogeneity does affect the co-seismic deformation, with the effects increasing with the medium's lateral heterogeneity caused by material parameters; 2) the Lame parameters play a more dominant role than density in the effects caused by lateral heterogeneity; 3) when a fault's dip angle is smaller than 90°, the effects of the medium's lateral heterogeneity on the hanging wall are greater than on the footwall; 4) the impact of lateral heterogeneity caused by the viscosity coefficient on the post-seismic deformation can affect a large area, including the near- and far-field.

Description: Publication date: Available online 23 March 2015 Source: Geodesy and Geodynamics Author(s): Tangyong Guo , Peiyuan Wang , Xin Li , Wei Zhu , Tong Zou , Shipeng Li , Qingshan Luo The mobile satellite laser ranging system TROS1000, successfully developed in 2010, achieves a high repetition rate and enables daytime laser ranging. Its measurement range has reached up to 36000 km with an accuracy as precise as 1 cm. Using recent observations in Wuhan, Jiufeng, Xianning, and Rongcheng, Shandong, we introduce the progress made using this mobile observation system.

Description: Publication date: Available online 23 March 2015 Source: Geodesy and Geodynamics Author(s): Haijun Xu , Yongzhi Zhang , Hurong Duan At present, gravity field and steady-state ocean circulation explorer (GOCE) gravity data are always used to compute regional gravity anomaly and geoid height. In this study, the latest GOCE gravity field model data (from Oct. 2009 to Jul. 2010) are used to compute the gravity gradient of mainland China according to a rigorous recursion formula (in all the six directions). The results show that the numerical values of the gravity gradients are larger in the T rr direction than those in the other directions. They reflect the terrain characteristics in detail and correlate with the regional tectonics; however, in the T θλ and T rλ directions, the numerical values are relatively smaller and the gravity gradients in the T rλ direction do not reflect the terrain characteristics in detail.

Description: Publication date: Available online 21 March 2015 Source: Geodesy and Geodynamics Author(s): Yaxuan Hu , Shanlan Qin , Ming Hao The recent plethora of GPS observations compensates for the 20-year-old lack in vertical displacement data for the Guanzhong region. The 2001–2007 three-dimensional (3D) crustal deformation data suggest regional movement with a horizontal velocity of 3–7 mm/a, predominantly from SSE in the west to SE in the east, and vertical inherited movement with velocity of −7 mm/a to 4 mm/a. After the Wenchuan earthquake, the GPS data suggest that the effect of the earthquake on the regional deformation is greater in the west than the east. The horizontal displacement increased during 2007–2008; however, the reverse was observed in 2008–2009. The vertical displacement in the western part of the region increased in 2008 and has been gradually returning to normal since 2009; however, in the eastern part, the effect of the earthquake remains.

Description: Publication date: Available online 11 April 2015 Source: Geodesy and Geodynamics Author(s): Jianyong Li , Guojie Meng , Xinzhao You , Rui Zhang , Hongbo Shi , Yufei Han Possible ionospheric disturbances relating to the May 12, 2008, M s8.0 Wenchuan earthquake were identified by Global Positioning System (GPS)-derived total electron content (TEC), ionosonde observations, the global ionospheric map (GIM), and electron density profiles detected by the Constellation Observation System for Meteorology Ionosphere and Climate (COSMIC). We applied a statistical test to detect anomalous TEC signals and found that a unique enhancement in TEC, recorded at 16 GPS stations, appeared on May 9, 2008. The critical frequency at F2 peak (f 0 F2), observed by the Chinese ionosondes, and maximal plasma frequency, derived from COSMIC data, revealed a characteristic similar to GPS TEC variations. The GIM showed that the anomalous variations of May 9 were located southeast of the epicenter. Using GPS data from 13 stations near the epicenter, we analyzed the TEC variations of satellite orbit traces during 04:00–11:00 UT. We found that TEC decreased to the east and increased to the southeast of the epicenter during this period. Results showed that the abnormal disturbance on May 9 was probably an ionospheric precursor of the Wenchuan earthquake of May 12, 2008.

Description: Publication date: Available online 23 March 2015 Source: Geodesy and Geodynamics Author(s): Yunzhong Shen , Xinzhao You , Jiexian Wang , Bin Wu , Junping Chen , Xiaping Ma , Xiuqiang Gong The seven co-located sites of the Crustal Movement Observation Network of China (CMONOC) in Shanghai, Wuhan, Kunming, Beijing, Xi'an, Changchun, and Urumqi are equipped with Global Navigation Satellite System (GNSS), very long baseline interferometry (VLBI), and satellite laser ranging (SLR) equipment. Co-location surveying of these sites was performed in 2012 and the accuracies of the solved tie vectors are approximately 5 mm. This paper proposes a mathematical model that handles the least squares adjustment of the 3D control network and calculates the tie vectors in one step, using all the available constraints in the adjustment. Using the new mathematical model, local tie vectors can be more precisely determined and their covariance more reasonably estimated.

Description: Publication date: Available online 24 March 2015 Source: Geodesy and Geodynamics Author(s): Xiaogang Liu , Yingchun Li , Yun Xiao , Bin Guan Downward continuation is a key step in processing airborne geomagnetic data. However, downward continuation is a typically ill-posed problem because its computation is unstable; thus, regularization methods are needed to realize effective continuation. According to the Poisson integral plane approximate relationship between observation and continuation data, the computation formulae combined with the fast Fourier transform (FFT) algorithm are transformed to a frequency domain for accelerating the computational speed. The iterative Tikhonov regularization method and the iterative Landweber regularization method are used in this paper to overcome instability and improve the precision of the results. The availability of these two iterative regularization methods in the frequency domain is validated by simulated geomagnetic data, and the continuation results show good precision.

Description: Publication date: Available online 9 April 2015 Source: International Journal of Sustainable Built Environment Author(s): Yousef Alhorr , Mohammed Arif , Tabassum Bano , Charles Egbu , Ahmed Mazroei , Esam Elsarrag Healing environment and Health Associated Infections (HAI) have been researched for more than 30 years globally. There is definitely a consensus among the researchers and practitioners about its importance. A range of issues such as knowledge management, performance management, design management and process management have been highlighted as major contributors to healing environment and HAI. This paper presents the results of a workshop conducted in Doha, Qatar with the purpose of exploring the problems encountered in the Qatari healthcare sector regarding HAI and healing environment. The major findings from the workshops indicated that there is a need for more research in the areas of knowledge management and performance management in order to better maintain healthcare facilities. The design of healthcare facilities and the implementation of green building guidelines in Qatar also need to incorporate design practices and features that can improve healing and have been researched in other parts of the world. This paper compiles the research agenda for future researchers to pursue and improve the performance and healing environment in Qatar.

Description: Publication date: Available online 2 May 2015 Source: International Journal of Sustainable Built Environment Author(s): Tara Sen , Ashim Paul This research paper presents an experimental investigation on the confinement strength and confinement modulus of concrete cylinders confined using different types of natural fibre composites and a comparative performance analysis with different artificial fibre based composite materials. The paper also highlights the need to switch over from the utilization of artificial fibres, which are non-renewable and fossil fuel products, to environmental beneficial materials like green fibres. The utilization of plant products like sisal and jute fibres and their composites in various structural engineering applications addresses the issues of sustainability and renewability with constructional materials. The paper describes a suitable mechanical treatment method like high temperature conditioning, which aids us in further improving the properties of these woven natural materials like sisal and jute for composite fabrication and utilization. Heat treated natural fibres of woven sisal and jute were utilized for confining concrete cylinders similar to CFRP and GFRP confinement and their confinement characteristics were obtained and compared. All the cylinders were subjected to monotonic axial compressive loads, so as to evaluate the effect of confinement on the axial load carrying capacity and all their failure modes were discussed thoroughly. The results indicated superior performance by sisal FRP as well as jute FRP confined cylinders as compared to controlled or unconfined cylinders, also sisal FRP wrapped cylinders displayed ultimate axial load of comparable magnitude to CFRP confinement. Natural FRP confinement displayed superior confinement modulus and confinement strength, also the ultimate axial load of concrete cylinders confined with natural FRPs underwent 66% enhancement by sisal FRP and 48% enhancement by jute FRP, in comparison with controlled or unconfined cylinders. Enhancement in axial load carrying capacity was 83% with CFRP confinement and 180% with GFRP confinement. Although natural FRP displayed lower enhancement in axial load carrying capacity in comparison with artificial FRP confinement, but enhanced load carrying capabilities alongside superior sustainability and environmental friendly indices could be obtained using the same, because of various advantages associated with the use of natural fibres.

Description: Publication date: Available online 18 March 2015 Source: International Journal of Sustainable Built Environment Author(s): Ashwani Kumar , Pushplata Urban settlements in India are growing tremendously and have critical issues related to uncontrolled and inappropriate development, environmental degradation, pollution, high energy consumption, and inefficient infrastructure which results in deteriorating living conditions. Therefore, achieving systematic and contextual development is the most challenging concern in all urban developments. This scenario is most critical in environmentally sensitive hill towns which have witnessed huge inappropriate development in last few decades. However, to achieve systematic and contextual development different building regulations like, floor area ratio (F.A.R.), setbacks, ground coverage, and height of building are enforced, but the problem of inappropriate development persists. Setback is a regulation which controls the spacing between buildings to have adequate solar exposure and ventilation. Presently, setback regulations are enforced uniformly throughout a hill town for a particular use which results in inadequate solar exposure to buildings, high energy consumption and unhealthy living conditions. This paper attempts to highlight a new approach to formulate setback regulations based on topography, slope direction, building height and access road for specific context to Shimla (the largest hilltop town of India) after the in depth study of problems of existing setback regulations in Indian hill towns.

Description: Publication date: Available online 1 April 2015 Source: International Journal of Sustainable Built Environment Author(s): Shaila Bantanur , Mahua Mukherjee , R. Shankar The institutions of higher education provide role models for excellence in education. But also have the added responsibility of providing guidance to the community for social upliftment and environmental sustainability. It becomes imperative, therefore to assess the extent to which sustainable practices have been adopted in these institutions and their adequacy. It is anticipated that a holistic assessment will indicate strengths and weaknesses in sustainability practices so that effective measures can be taken to initiate the creation of a more sustainable environment. To achieve the foregoing objective parameters like Land use and Energy have been identified. An analysis of the basic sustainability parameters with regard to the various institutional surveys indicates the changing trends over the years. The trend reflects institutional growth, improvement in the economy and growing of awareness of sustaining the ecological environment. However, the extent to which each parameter is addressed varies from institution to institution, as well as the geographical location and climatic variations due to the diverse nature of these two factors in the Indian context. Increasing awareness issues pertaining to sustainability in institutions of higher education is reflected by relevant practices adopted, however it is expected that initial momentum generated in this direction will lead to further adoption of sustainable practices consistent with the cultural geographical and socio economic scenario prevailing.

Description: Publication date: Available online 30 April 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Mikhail A. Guzev

Description: Publication date: Available online 28 April 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Gamal Rashed , Syd S. Peng Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine workings. Previous studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height (W/H) ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.

Description: Publication date: Available online 7 April 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Jianping Zuo , Huihai Liu , Hongtao Li This study uses a three-dimensional crack model to theoretically derive the Hoek–Brown rock failure criterion based on the linear elastic fracture theory. Specifically, we argue that a failure characteristic factor needs to exceed a critical value when macro-failure occurs. This factor is a product of the micro-failure orientation angle (characterizing the density and orientation of damaged micro-cracks) and the changing rate of the angle with respect to the major principal stress (characterizing the microscopic stability of damaged cracks). We further demonstrate that the factor mathematically leads to the empirical Hoek–Brown rock failure criterion. Thus, the proposed factor is able to successfully relate the evolution of microscopic damaged crack characteristics to macro-failure. Based on this theoretical development, we also propose a quantitative relationship between the brittle–ductile transition point and confining pressure, which is consistent with experimental observations.

Description: Publication date: Available online 18 April 2015 Source: Journal of Hydrology: Regional Studies Author(s): Fabrice Papa , Frédéric Frappart , Yoann Malbeteau , Mohammad Shamsudduha , Venugopal Vuruputur , Muddu Sekhar , Guillaume Ramillien , Catherine Prigent , Filipe Aires , Rajesh Kumar Pandey , Sujit Bala , Stephane Calmant Study region The Ganges–Brahmaputra (GB), a major river basin of the Indian Sub-Continent (ISC), is the host of more than 700 millions people. Study focus In addition to monsoons and strong climate variability, GB is facing growing demands for freshwater availability by a continually growing population and rapidly developing of agricultural and industrial sectors. The management of water resources is thus of highest priority and, in the context of current over-abstraction of groundwater, accurate estimates of terrestrial freshwater storage are essential. We propose a multi-satellite approach to estimate surface freshwater storage (SWS) and subsurface water storage (SSWS, groundwater + soil moisture) variations over GB. New hydrological insights Basin-scale monthly SWS variations for the period 2003–2007 show a mean annual amplitude of ∼410 km 3 , contributing to about 45% of the Gravity Recovery And Climate Experiment (GRACE)-derived total water storage variations (TWS). During the drought-like conditions in 2006, we estimate that the SWS deficit over the entire GB basin in July–August–September was about 30% as compared to other years. The SWS variations are then used to decompose the GB GRACE-derived TWS and isolate the variations of SSWS whose mean annual amplitude is estimated to be ∼550 km 3 . This new dataset of water storage variations represent an unprecedented source of information for hydrological and climate modeling studies of the ISC.

Description: Publication date: Available online 7 April 2015 Source: Journal of Hydrology: Regional Studies Author(s): Swati Verma , Abhijit Mukherjee , Runti Choudhury , Chandan Mahanta Study region Brahmaputra River basin, India. Study focus The present study deciphers the groundwater solute chemistry and arsenic (As) enrichment in the shallow aquifers of the study region. Four different geomorphologic units, e.g. piedmont (PD), older alluvium of river Brahmaputra and its tributaries (OA), active alluvium of river Brahmaputra and its tributaries (YA) and river channel deposits (RCD) were identified. More than 62% of all groundwater samples collected have dissolved As >0.01 mg/L, whereas about 87% of groundwater samples in OA terrain are enriched with As, which draws a distinct difference from the adjoining Gangetic aquifers. New hydrological insights for the region Most groundwater solutes of RCD and YA terrains were derived from both silicate weathering and carbonate dissolution, while silicate weathering process dominates the solute contribution in OA groundwater. Groundwater samples from all terrains are postoxic with mean pe values between Fe(III) and As(V)–As(III) reductive transition. While, reductive dissolution of (Fe–Mn)OOH is the dominant mechanism of As mobilization in RCD and YA aquifers, As in OA and PD aquifers could be mobilized by combined effect of pH dependent sorption and competitive ion exchange. The present study focuses on the major ion chemistry as well as the chemistry of the redox sensitive solutes of the groundwater in different geomorphic settings and their links to arsenic mobilization in groundwater.

Description: Publication date: Available online 11 March 2015 Source: Journal of Hydrology: Regional Studies Author(s): B.M. Hallett , H.A. Dharmagunawardhane , S. Atal , E. Valsami-Jones , S. Ahmed , W.G. Burgess Study region The Maheshwaram and Waipally catchments of Andhra Pradesh, India, and the Plonnaruwa catchment of north-central Sri Lanka. Study focus The distribution of F across eight crystalline phases and between the bedrock and the regolith at eleven sites in three catchments is documented. Mineral contributions to F release during weathering and regolith development are quantified. New hydrological insights for the region An estimate of weathering duration for the in situ regolith in Andhra Pradesh, 250–380 Ka, is close to a previous estimate for southern India. Partial or total destruction of the primary F-bearing bedrock minerals and consistent depletion of F in the remnant minerals result in a much reduced total F content in the regolith. Leaching experiments and field relationships, however, indicate a greater potential for F mobilisation to groundwater from the regolith than the bedrock. Schemes for managed aquifer recharge should beware the risk of mobilising additional F to groundwater.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1 Author(s): Salah Er-Raki

Description: Publication date: Available online 9 May 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Zhiqiang Liu , Yiping Meng This study presents the concept of shaft constructed by raise boring in underground mines, and the idea of inverse construction can be extended to other fields of underground engineering. The conventional raise boring methods, such as the wood support method, the hanging cage method, the creeping cage method, and the deep-hole blasting method, are analyzed and compared. In addition, the raise boring machines are classified into different types and the characteristics of each type are described. The components of a raise boring machine including the drill rig, the drill string and the auxiliary system are also presented. Based on the analysis of the raise boring method, the rock mechanics problems during the raise boring process are put forward, including rock fragmentation, removal of cuttings, shaft wall stability, and borehole deviation control. Finally, the development trends of raise boring technology are described as follows: (i) improvement of rock-breaking modes to raise drilling efficiency, (ii) development of an intelligent control technique, and (iii) development of technology and equipment for nonlinear raise boring.

Description: Publication date: Available online 12 June 2015 Source: International Journal of Sustainable Built Environment Author(s): Nitendra Palankar , A.U. Ravi Shankar , Mithun BM The present day research is focussed on development of alternative binder materials to Ordinary Portland Cement (OPC) due to huge emissions of green house gases associated with production of OPC. GGBFS-FA based geopolymer binders are an innovative alternative to OPC which can obtain high strengths apart from being eco-friendly; since its production does not involve high energy and also contributes to sustainability by using the industrial waste materials. Steel slag, an industrial by-product obtained from manufacture of steel can be identified as an alternative to natural aggregates for concrete production, since there is a possibility of acute shortage of natural aggregates in future. The present study is conducted to evaluate the performance of weathered steel slag coarse aggregates in GGBFS-FA based geopolymer concrete. GGBFS-FA geopolymer concrete with steel slag coarse aggregates are prepared by replacing natural granite aggregates at different replacement levels i.e. 0%, 25%, 50%, 75% and 100% (by volume) and various fresh and mechanical properties are studied. The flexural fatigue behaviour of GGBFS-FA geopolymer concrete with steel slag is also studied in detail. Efforts are also made to model the probabilistic distribution of fatigue data of GGBFS-FA geopolymer concrete at different stress levels using two parameters Weibull distribution. The results indicated that incorporation of steel slag in GGBFS-FA geopolymer concrete resulted in slight reduction in mechanical strength. The water absorption and volume of permeable voids displayed higher values with inclusion of steel slag. Reduction in number of cycles for fatigue failure was observed in geopolymer concrete mixes containing steel slag as compared to granite aggregates. Overall, the performance of steel slag was found to be satisfactory for structural and pavement application and steel slag can recognised as new construction material.

Description: Publication date: Available online 11 June 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Asskar Janalizadeh , Ali Zahmatkesh Liquefaction has been a main cause of damage to civil engineering structures in seismically active areas. The effects of damage of liquefaction on deep foundations are very destructive. Seismic behavior of pile foundations is widely discussed by many researchers for safer and more economic design purposes. This paper presents a pseudo-static method for analysis of piles in liquefiable soil under seismic loads. A free-field site response analysis using three-dimensional (3D) numerical modeling was performed to determine kinematic loads from lateral ground displacements and inertial loads from vibration of the superstructure. The effects of various parameters, such as soil layering, kinematic and inertial forces, boundary condition of pile head and ground slope, on pile response were studied. By comparing the numerical results with the centrifuge test results, it can be concluded that the use of the p - y curves with various degradation factors in liquefiable sand gives reasonable results.

Description: Publication date: Available online 28 December 2015 Source: Geodesy and Geodynamics Author(s): Jin Li, WenBin Shen, Xuhua Zhou Earth's gravity model (EGM) helps people better determine the figure of Earth, which is generally represented by a global geoid. For a considerable amount of practical applications, people use quasi-geoid to approximate the geoid, thus the quasi-geoid is also treated as an important height datum. In this study we revisit the method to directly determine regional quasi-geoid using EGM and digital elevation model (DEM), on the basis of Molodensky theory. According to the method we obtain a 5′ × 5′ quasi-geoid for Mainland China and its vicinity areas, based on the EGM2008 gravitational potential model and the Shuttle Radar Topography Mission (SRTM) DEM model. By comparing height anomalies derived from EGM2008 with observations at 70 GPS/leveling points in areas including northwest, mid-west, mid-east and southeast of China, we find that the 5′ × 5′ EGM2008 quasi-geoid well fits the GPS/leveling results, with average deviations less than 10 cm for the selected areas in east China (with mainly plain topography) and ∼20 cm for the selected areas in west China (highland or mountainous areas). We also discuss a few technical issues for directly determining height anomalies based on EGM and DEM, under the frame of Molodensky theory.

Description: Publication date: Available online 28 December 2015 Source: Geodesy and Geodynamics Author(s): Youssef Timoulali, Nacer Jabour, Youssef Hahou, Mimoun Chourak This study presents the outcomes of the local earthquake tomography applied in the Moroccan Atlas domains. A seismic data collected by 36 seismic and a linearized inversion technics are used for determination of local velocity structure. The interpretation of tomography images results emphasizes a new and detailed lithosphere structure: a remaining subducted zone beneath the Souss Basin located from 20- to 45-km depth dipping to the North is detected and interpreted as a body that marks the border between the Moroccan Anti-Atlas and the Meseta-Atlas domains. A subduction zones is detected in the SW of the High Atlas, beneath the Hercynian Tichka massif from 10 to 50-km inclined away from Anti Atlas and in the eastern part of Anti Atlas, dipping northward from Jbel Ougnat at 15–40 km. The junction of the western and middle High Atlas is depicted by two high velocity blocks subducting from 10 to 50 km depth. The first is dipping SW beneath the High Atlas and the second is dipping SE beneath the Ouarzazate Basin. In the northern part of the southwestern High Atlas, a high velocity body dipping towards the north beneath the Essaouira Basin from 15 to 45 km depth. In northeastern part of the High Atlas in the Mougeur zone, a high velocity body is detected from 10 to 45 km depth, dipping to the S–E beneath the eastern High Atlas. The negative lithospheric anomalies found in the upper and in the lower crust are interpreted as a hot asthenospheric material upwelling from deep and gradually replacing the part of crust detached in the High Atlas. The occurrence magmatic activities in these regions testify the existence of a remaining subduction process. This paper argues the implication of these deep structures in the evolution of the Moroccan Atlas Mountain.

Description: Publication date: Available online 29 December 2015 Source: Geodesy and Geodynamics Author(s): Fuqiong Huang, Yong Chen, Ping Ji, Kexin Ren, Fuwang Gao, Lingkong Zhang The Kunlunshan Mountain M s8.1 earthquake, occurred in Nov.14, 2001, is the first event with magnitude more than 8 in the China earthquake monitoring history, specifically at the beginning of digital techniques in precursor monitoring networks. Any investigation of recorded data on this earthquake is very important for testing the operation of the digital monitoring networks and understanding the preparation, occurrence, and adjustment of stress/strain of strong continental earthquakes. In this paper we investigated the co-seismic response changes of well water level of groundwater and volume strain meter of bore hole in digital earthquake monitoring network of Capital area and its vicinity, due to the Nov.14, 2001 M s8.1 Kunlun Mountain earthquake. The responding time, shapes or manners, amplitudes, and lasting time of well water level and strain-meters to seismic wave are studied in comparison. Then we discussed the possibility that the response changes of groundwater to strong distant earthquakes can be understood as one kind of observing evidence of stress/strain changes induced by distant earthquake.

Description: Publication date: Available online 29 December 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Yankun Sun, Qi Li, Duoxing Yang, Xuehao Liu Carbon dioxide (CO 2 ) geosequestration in deep saline aquifers has been currently deemed as a preferable and practicable mitigation means for reducing anthropogenic greenhouse gases (GHGs) emissions to the atmosphere, as deep saline aquifers can offer the greatest potential from a capacity point of view. Hence, research on core-scale CO 2 /brine multiphase migration processes is of great significance for precisely estimating storage efficiency, ensuring storage security, and predicting the long-term effects of the sequestered CO 2 in subsurface saline aquifers. This review article initially presents a brief description of the essential aspects of CO 2 subsurface transport and geological trapping mechanisms, and then outlines the state-of-the-art laboratory core flooding experimental apparatus that has been adopted for simulating CO 2 injection and migration processes in the literature over the past decade. Finally, a summary of the characteristics, components and applications of publicly reported core flooding equipment as well as major research gaps and areas in need of further study are given in relevance to laboratory-scale core flooding experiments in CO 2 geosequestration under reservoir conditions.

Description: Publication date: Available online 10 December 2015 Source: Journal of Hydrology: Regional Studies Author(s): Tatsuya Utsunomiya, Masaki Hata, Ryo Sugimoto, Hisami Honda, Shiho Kobayashi, Yoji Miyata, Makoto Yamada, Osamu Tominaga, Jun Shoji, Makoto Taniguchi Study focus There have been far more studies on how the variability in surface water discharge affects production of animal communities in aquatic ecosystems while less information has been accumulated on the mechanisms of how the groundwater supply works. Study region Physical and biological surveys were conducted to test the hypothesis that high level of submarine ground water discharge enhances species richness, abundance and biomass of fishes and invertebrates in coastal waters of Obama Bay, Japan, where a high contribution of nutrients (ca. 65% of phosphorus) to total provided through all freshwater has been reported. Survey for horizontal distribution of radon-222 ( 222 Rn) concentration showed high levels of submarine groundwater discharge in the west part of survey area. Fish and invertebrate communities were compared within a relatively small spatial scale (ca. 100 m) in relation to level of submarine groundwater discharge. New hydrological insights Species richness, abundance and biomass of fishes and abundance and biomass of turban snail and hermit crab were significantly higher in the area with high 222 Rn concentration. Abundance of gammarids, the most major prey item of the fishes, was 18 times higher in the area with high 222 Rn concentration. Since the turban snail, hermit crab and gammarids feed on producers (phytoplankton and benthic microalgae), submarine groundwater are concluded to increase species richness and production of fishes and invertebrates through providing nutrients and enhancing primary production.

Description: Publication date: March 2016 Source: Journal of Hydrology: Regional Studies, Volume 5 Author(s): A.C. de la Casa, G.G. Ovando Study region Changes in reference evapotranspiration (ET o ) may have important consequences for agricultural suitability in the central region of Argentina. Annual ET o variation was assessed, in terms of both territory and time, for the 7 decades between 1941 and 2010, analyzing the behavior of the 4 atmospheric variables which determine it: temperature, vapor pressure, wind speed and cloud cover. Study focus The influence of each variable on ET o was evaluated from a multiple regression model and a simple correlation analysis, using climate data from the observation network, and repeating this analysis using interpolated variables. In this grid scheme, linear relationships were determined between ET o and the different key atmospheric variables, plus precipitation (PP), and the t test was applied to establish the statistically significant sectors ( P 〈 0.1). Then, those areas with a significant trend change ( P 〈 0.1) were determined by the Mann–Kendall test. Finally, the interception of the grids was performed to establish their joint occurrence. New hydrological insights for the region Most of the region analyzed (>91%) presents a non-significant variation of ET o over time, with a mostly non-significant change of each driving variable, regarding both its relationship with ET o and its own trend of change. The beneficial change in agricultural suitability reported for this water-limited region was found to be produced almost exclusively by increasing PP. Graphical abstract

Description: Publication date: Available online 11 December 2015 Source: Journal of Hydrology: Regional Studies Author(s): Makoto Taniguchi, Naoki Masuhara, Kimberly Burnett Security measures of three resources; water, energy and food are analyzed for thirty two countries in the Asia Pacific region which are faced to Pacific Ocean, in terms of amounts of the resource, self-production, and diversity of sources of each resource. Diversity for all the three resources is also analyzed using surface water and groundwater for water sources; hydro power, geothermal power, solar, and biomass for energy; and cereals, vegetable, fruit, meat, and fish for food. We see high diversity of sources of water in the US and the Philippines, and a low diversity of sources of food in the US, Canada, and Indonesia. These security measures including water security show new hydrological insight for Asia-Pacific region.

Description: Publication date: Available online 10 December 2015 Source: Journal of Hydrology: Regional Studies Author(s): Aiko Endo, Izumi Tsurita, Kimberly Burnett, Pedcris M. Orencio Study region Asia, Europe, Oceania, North America, South America, Middle East and Africa. Study focus The purpose of this paper is to review and analyze the water, energy, and food nexus and regions of study, nexus keywords and stakeholders in order to understand the current state of nexus research. New hydrological insights Through selected 37 projects, four types of nexus research were identified including water–food, water–energy–food, water–energy, and climate related. Among them, six projects (16%) had a close linkage with water–food, 11 (30%) with water–energy–food, 12 (32%) with water–energy, and eight (22%) with climate. The regions were divided into Asia, Europe, Oceania, North America, South America, Middle East and Africa. North America and Oceania had a tendency to focus on a specific nexus type, water–energy (46%) and climate (43%), while Africa had less focus on water–energy (7%). Regarding keywords, out of 37 nexus projects, 16 projects listed keywords in their articles. There were 84 keywords in total, which were categorized by the author team depending on its relevance to water, food, energy, climate, and combination of water–food–energy–climate, and 40 out of 84 keywords were linked with water and only 4 were linked with climate. As for stakeholders, 77 out of 137 organizations were related to research and only two organizations had a role in media.

Description: Publication date: March 2016 Source: Journal of Hydrology: Regional Studies, Volume 5 Author(s): Shilpa M. Asokan, Peter Rogberg, Arvid Bring, Jerker Jarsjö, Georgia Destouni Study region The large semi-arid Aral Region in Central Asia and the smaller tropical Mahanadi River Basin (MRB) in India. Study focus Few studies have so far evaluated the performance of the latest generation of global climate models on hydrological basin scales. We here investigate the performance and projections of the global climate models in the Coupled Model Intercomparison Project, Phase 5 (CMIP5) for freshwater fluxes and their changes in two regional hydrological basins, which are both irrigated but of different scale and with different climate. New hydrological insights for the region For precipitation in both regions, model accuracy relative to observations has remained the same or decreased in successive climate model generations until and including CMIP5. No single climate model out-performs other models across all key freshwater variables in any of the investigated basins. Scale effects are not evident from global model application directly to freshwater assessment for the two basins of widely different size. Overall, model results are less accurate and more uncertain for freshwater fluxes than for temperature, and particularly so for model-implied water storage changes. Also, the monsoon-driven runoff seasonality in MRB is not accurately reproduced. Model projections agree on evapotranspiration increase in both regions until the climatic period 2070–2099. This increase is fed by precipitation increase in MRB and by runoff water (thereby decreasing runoff) in the Aral Region.

Description: Publication date: March 2016 Source: Journal of Hydrology: Regional Studies, Volume 5 Author(s): Justin A. Schulte, Raymond G. Najjar, Ming Li Study region The Mid-Atlantic region of the United States. Study focus An understanding of past streamflow variability is necessary for developing future management practices that will help mitigate the impacts of extreme events such as drought or floods on agriculture and other human activities. To better understand mechanisms driving streamflow variability at all timescales, annual to multi-decadal streamflow variability of three major rivers in the Mid-Atlantic region of the United States (the Susquehanna, Delaware, and Hudson Rivers) was studied in the context of climate modes using correlation and wavelet analyses. New hydrological insights for the region Results from the correlation analysis detected statistically significant relationships between climate indices and streamflow that were similar for the three rivers. The results from the wavelet analysis showed that 18- and 26-year periodicities were embedded in the streamflow time series. Decadal variability of streamflow was coherent with the El-Niño Southern Oscillation (SO) and the Pacific Decadal Oscillation (PDO). The time series for the PDO and SO indices and precipitation were found to be synchronized to the decadal variability of a global circulation pattern consisting of a Rossby wave train emanating from the North Pacific. The SO explained 37–54% of the 1960s drought, 33–49% of the 1970s pluvial, and 19–50% of the 2000s pluvial in the three river basins.

Description: Publication date: Available online 24 December 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Matthew A. Perras, Mark S. Diederichs During the construction of an underground excavation, damage occurs in the surrounding rock mass due in large part to stress changes. While the predicted damage extent impacts profile selection and support design, the depth of damage is a critical aspect for the design of permeability sensitive excavations, such as a deep geological repository (DGR) for nuclear waste. Review of literature regarding the depth of excavation damage zones (EDZs) indicates three zones are common and typically related to stress induced damage. Based on past developments related to brittle damage prediction using continuum modelling, the depth of the EDZs has been examined numerically. One method to capture stress induced damage in conventional engineering software is the damage initiation and spalling limit (DISL) approach. The variability of depths predicted using the DISL approach has been evaluated and guidelines are suggested for determining the depth of the EDZs around circular excavations in brittle rock masses. Of the inputs evaluated, it was found that the tensile strength produces the greatest variation in the depth of the EDZs. The results were evaluated statistically to determine the best fit relation between the model inputs and the depth of the EDZs. The best correlation and least variation were found for the outer EDZ and the highly damaged zone (HDZ) showed the greatest variation. Predictive equations for different EDZs have been suggested and the maximum numerical EDZ depths, represented by the 68% prediction interval, agreed well with the empirical evidence. This suggests that the numerical limits can be used for preliminary depth prediction of the EDZs in brittle rock for circular excavations.

Description: Publication date: Available online 29 December 2015 Source: Geodesy and Geodynamics Author(s): Hongtao Hao, Jin Wei, Minzhang Hu, Ziwei Liu, Hui Li Using mobile gravity data from the central area of Sichuan and Yunnan Provinces, the relationship between gravity variation and earthquakes was studied based on the Ludian M s6.5 earthquake that occurred on August 3rd, 2014, and the Kangding M s6.3 earthquake that occurred on November 22nd, 2014; the mechanism of gravity variation was also explored. The results are as follows: (1) Prior to both earthquakes, gravity variation exhibited similar characteristics as those observed before both the Tangshan and Wenchuan earthquakes, in which typical precursor anomalies were positive gravity variation near the epicenter and the occurrence of a high-gravity-gradient zone across the epicenter prior to the earthquake. (2) A relatively accurate prediction of the occurrence locations of the two earthquakes was made by the Gravity Network Center of China (GNCC) based on these precursor anomalies. In the gravity study report on the 2014 earthquake trends submitted at the end of 2013, the Daofu-Shimian section at the junction of the Xianshuihe and Longmenshan fault zones was noted as an earthquake-risk region with a predicted magnitude of 6.5, which covered the epicenter of the Kangding M s6.3 earthquake. In another report on earthquake trends in southwestern China submitted in mid-2014, the Lianfeng, Zhaotong fault zone was also classified as an earthquake-risk region with a magnitude of 6.0, and the central area of this region basically overlapped with the epicenter of the Ludian M s6.5 earthquake. (3) The gravity variation characteristics are reasonably consistent with crustal movements, and deep material migration is likely the primary cause of gravity variation.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: Available online 16 June 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Mingqing You Estimating in-situ stress with hydraulic borehole fracturing involves tensile strength of rock. Several strength criteria with three parameters result in tensile strengths with great differences, although they may describe the relation between strength of rock and confining pressure with low misfits. The exponential criterion provides acceptable magnitudes of tensile strengths for granites and over-estimates that for other rocks, but the criterion with tension cut-off is applicable to all rocks. The breakdown pressure will be lower than the shut-in pressure during hydraulic borehole fracturing, when the maximum horizontal principal stress is 2 times larger than the minor one; and it is not the peak value in the first cycle, but the point where the slope of pressure-time curve begins to decline.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Abdouramane Gado Djibo , Ousmane Seidou , Harouna Karambiri , Ketevera Sittichok , Jean Emmanuel Paturel , Hadiza Moussa Saley Study region The Sirba watershed, Niger and Burkina Faso countries, West Africa. Study focus Water resources management in the Sahel region, West Africa, is extremely difficult because of high inter-annual rainfall variability. Unexpected floods and droughts often lead to severe humanitarian crises. Seasonal rainfall forecasting is one possible way to increase resilience to climate variability by providing information in advance about the amount of rainfall expected in each upcoming rainy season. Rainfall forecasting models often arbitrarily assume that rainfall is linked to predictors by a multiple linear regression with parameters that are independent of time and of predictor magnitude. Two probabilistic methods based on change point detection that allow the relationship to change according to time or rainfall magnitude were developed in this paper using normalized Bayes factors. Each method uses one of the following predictors: sea level pressure, air temperature and relative humidity. Method M1 allows for change in model parameters according to annual rainfall magnitude, while M2 allows for changes in model parameters with time. M1 and M2 were compared to the classical linear model with constant parameters (M3) and to the climatology (M4). New hydrological insights for the region The model that allows a change in the predictor–predictand relationship according to rainfall amplitude (M1) and uses air temperature as predictor is the best model for seasonal rainfall forecasting in the study area.

Description: Publication date: Available online 5 August 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Iyad S. Alkroosh, Mohammad Bahadori, Hamid Nikraz, Alireza Bahadori In this study, the least square support vector machine (LSSVM) algorithm was applied to predicting the bearing capacity of bored piles embedded in sand and mixed soils. Pile geometry and cone penetration test (CPT) results were used as input variables for prediction of pile bearing capacity. The data used were collected from the existing literature and consisted of 50 case records. The application of LSSVM was carried out by dividing the data into three sets: a training set for learning the problem and obtaining a relationship between input variables and pile bearing capacity, and testing and validation sets for evaluation of the predictive and generalization ability of the obtained relationship. The predictions of pile bearing capacity by LSSVM were evaluated by comparing with experimental data and with those by traditional CPT-based methods and the gene expression programming (GEP) model. It was found that the LSSVM performs well with coefficient of determination, mean, and standard deviation equivalent to 0.99, 1.03, and 0.08, respectively, for the testing set, and 1, 1.04, and 0.11, respectively, for the validation set. The low values of the calculated mean squared error and mean absolute error indicated that the LSSVM was accurate in predicting the pile bearing capacity. The results of comparison also showed that the proposed algorithm predicted the pile bearing capacity more accurately than the traditional methods including the GEP model.

Description: Publication date: Available online 4 August 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Tariq Siddique, M.Masroor Alam, M.E.A. Mondal, V. Vishal The road network in the Himalayan terrain, connecting remote areas either in the valleys or on the hill slopes, plays a pivotal role in socio-economic development of India. The planning, development and even maintenance of road and rail networks in such precarious terrains are always a challenging task because of complexities posed by topography, geological structures, varied lithology and neotectonics. Increasing population and construction of roads have led to destabilisation of slopes, thus leading to mass wasting and movement, further aggravation due to recent events of cloud bursts and unprecedented flash floods. Vulnerability analysis of slopes is an important component for the “Landslide Hazard Assessment” and “Slope Mass Characterisation” guide planners to predict and choose suitable ways for construction of roads and other engineering structures. The problem of landslides along the national highway-58 (NH-58) from Rishikesh to Devprayag is a common scene. The slopes along the NH-58 between Jonk and Rishikesh were investigated, which experienced very heavy traffic especially from March to August due to pilgrimage to Kedarnath shrine. On the basis of slope mass rating (SMR) investigation, the area falls in stable class, and landslide susceptibility score (LSS) values also indicate that the slopes under investigation fall in low to moderate vulnerability to landslide. More attentions should be paid to the slopes to achieve greater safe and economic benefits along the highway.

Description: Publication date: Available online 4 August 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Arash Ebrahimabadi, Mohammad Azimipour, Ali Bahreini Application of mechanical excavators is one of the most commonly used excavation methods because it can bring the project more productivity, accuracy and safety. Among the mechanical excavators, roadheaders are mechanical miners which have been extensively used in tunneling, mining and civil industries. Performance prediction is an important issue for successful roadheader application and generally deals with machine selection, production rate and bit consumption. The main aim of this research is to investigate the cutting performance (instantaneous cutting rates (ICRs)) of medium-duty roadheaders by using artificial neural network (ANN) approach. There are different categories for ANNs, but based on training algorithm there are two main kinds: supervised and unsupervised. The multi-layer perceptron (MLP) and Kohonen self-organizing feature map (KSOFM) are the most widely used neural networks for supervised and unsupervised ones, respectively. For gaining this goal, a database was primarily provided from roadheaders’ performance and geomechanical characteristics of rock formations in tunnels and drift galleries in Tabas coal mine, the largest and the only fully-mechanized coal mine in Iran. Then the database was analyzed in order to yield the most important factor for ICR by using relatively important factor in which Garson equation was utilized. The MLP network was trained by 3 input parameters including rock mass properties, rock quality designation (RQD), intact rock properties such as uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS), and one output parameter (ICR). In order to have more validation on MLP outputs, KSOFM visualization was applied. The mean square error (MSE) and regression coefficient ( R ) of MLP were found to be 5.49 and 0.97, respectively. Moreover, KSOFM network has a map size of 8×5 and final quantization and topographic errors were 0.383 and 0.032, respectively. The results show that MLP neural networks have a strong capability to predict and evaluate the performance of medium-duty roadheaders in coal measure rocks. Furthermore, it is concluded that KSOFM neural network is an efficient way for understanding system behavior and knowledge extraction. Finally, it is indicated that UCS has more influence on ICR by applying the best trained MLP network weights in Garson equation which is also confirmed by KSOFM.

Description: Publication date: Available online 4 August 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): Jianping Zuo, Wei Xu, Jianliang Pei, Xiaoping Zhao In this study, the meso-failure mechanism and fracture surface of Jinping marble were investigated by means of scanning electron microscope (SEM) with bending loading system and laser-scanner equipment. The Yantang and Baishan marbles specimens from Jinping II hydropower station were used. Test results show that the fracture toughness and mechanical behaviors of Yantang marble were basically higher than those of Baishan marble. This is mainly due to the fact that Baishan marble contains a large percentage of dolomite and minor mica. Crack propagation path and fracture morphology indicated that the direction of tensile stress has a significant effect on the mechanical behaviors and fracture toughness of Baishan marble. For Yantang and Baishan marbles, a large number of microcracks around the main crack tip were observed when the direction of tensile stress was parallel to the bedding plane. Conversely few microcracks occurred when the direction of tensile stress was perpendicular to the bedding plane. The presence of a large number of microcracks at the main crack tip decreased the global fracture toughness of marble. The results of three-point bending tests showed that the average bearing capacity of intact marble is 3.4 times the notched marble, but the ductility property of the defective marble after peak load is better than that of the intact marble. Hence large deformation may be generated before failure of intact marbles at Jinping II hydropower station. The fractal dimension of fracture surface was also calculated by the cube covering method. Observational result showed that the largest fractal dimension of Yantang marble is captured when the direction of tensile stress is parallel to the bedding plane. However, the fractal dimension of fracture surface of Yantang and Baishan marbles with tensile stress vertical to the bedding plane is relatively small. The fractal dimension can also be used to characterize the roughness of fracture surface of rock materials.

Description: Publication date: Available online 15 July 2015 Source: Geodesy and Geodynamics Author(s): Wei Feng, Min Zhong Total sea level variations (SLVs) are caused by two major components: steric variations due to thermal expansion of seawater, and mass-induced variations due to mass exchange between ocean and land. In this study, the global SLV and its steric and mass components were estimated by satellite altimetry, Argo float data and the Gravity Recovery and Climate Experiment (GRACE) data over 2005–2014. Space gravimetry observations from GRACE suggested that two-thirds of the global mean sea level rise rate observed by altimetry (i.e., 3.1 ± 0.3 mm/a from 2005 to 2014) could be explained by an increase in ocean mass. Furthermore, the global mean sea level was observed to drop significantly during the November, 2010 La Niña event, which may be attributed to the decline of ocean mass and steric SLV. Since early 2011, the global mean sea level began to rise rapidly, which was attributed to an increase in ocean mass. The findings in this study suggested that the global mean sea-level budget was closed from 2005 to 2014 based on altimetry, GRACE, and Argo data.

Description: Publication date: Available online 17 July 2015 Source: Geodesy and Geodynamics Author(s): Wang Changqing, Xu Houze, Zhong Min, Feng Wei The Gravity Recovery and Climate Experiment (GRACE) mission can significantly improve our knowledge of the temporal variability of the Earth's gravity field. We obtained monthly gravity field solutions based on variational equations approach from GPS-derived positions of GRACE satellites and K-band range-rate measurements. The impact of different fixed data weighting ratio in temporal gravity field recovery while combining the two types of data were investigated for the purpose of deriving the best combined solution. The monthly gravity field solution obtained through above procedures was named as the Institute of Geodesy and Geophysics (IGG) temporal gravity field model. IGG temporal gravity field models were compared with GRACE Release05 (RL05) products in following aspects: (i) the trend of the mass anomaly in China and its nearby regions within 2005–2010; (ii) the root mean squares of the global mass anomaly during 2005–2010; (iii) time-series changes in the mean water storage in the region of the Amazon Basin and the Sahara Desert between 2005 and 2010. The results showed that IGG solutions were almost consistent with GRACE RL05 products in above aspects (i)–(iii). Changes in the annual amplitude of mean water storage in the Amazon Basin were 14.7 ± 1.2 cm for IGG, 17.1 ± 1.3 cm for the Centre for Space Research (CSR), 16.4 ± 0.9 cm for the GeoForschungsZentrum (GFZ) and 16.9 ± 1.2 cm for the Jet Propulsion Laboratory (JPL) in terms of equivalent water height (EWH), respectively. The root mean squares of the mean mass anomaly in Sahara were 1.2 cm, 0.9 cm, 0.9 cm and 1.2 cm for temporal gravity field models of IGG, CSR, GFZ and JPL, respectively. Comparison suggested that IGG temporal gravity field solutions were at the same accuracy level with the latest temporal gravity field solutions published by CSR, GFZ and JPL.

Description: Publication date: Available online 17 July 2015 Source: Geodesy and Geodynamics Author(s): Wang Hansheng, Xiang Longwei, Jia Lulu, Wu Patrick, Holger Steffen, Jiang Liming, Shen Qiang As global warming continues, the monitoring of changes in terrestrial water storage becomes increasingly important since it plays a critical role in understanding global change and water resource management. In North America as elsewhere in the world, changes in water resources strongly impact agriculture and animal husbandry. From a combination of Gravity Recovery and Climate Experiment (GRACE) gravity and Global Positioning System (GPS) data, it is recently found that water storage from August, 2002 to March, 2011 recovered after the extreme Canadian Prairies drought between 1999 and 2005. In this paper, we use GRACE monthly gravity data of Release 5 to track the water storage change from August, 2002 to June, 2014. In Canadian Prairies and the Great Lakes areas, the total water storage is found to have increased during the last decade by a rate of 73.8 ± 14.5 Gt/a, which is larger than that found in the previous study due to the longer time span of GRACE observations used and the reduction of the leakage error. We also find a long term decrease of water storage at a rate of −12.0 ± 4.2 Gt/a in Ungava Peninsula, possibly due to permafrost degradation and less snow accumulation during the winter in the region. In addition, the effect of total mass gain in the surveyed area, on present-day sea level, amounts to −0.18 mm/a, and thus should be taken into account in studies of global sea level change.

Description: Publication date: Available online 28 August 2015 Source: Geodesy and Geodynamics Author(s): Ming Hao, Shanlan Qin, Qingliang Wang, Jianhua Wang, Lin Zhou The correction for antenna phase center is considered in processing Global Positioning System (GPS) data collected from a network of GPS ultra-short baselines. Compared with the leveling measurements, the GPS results show that the relative vertical offsets for the pairs of GPS receiver antenna phase centers still exist, although absolute calibration of the antenna phase center variations (PCVs) has been considered. With respect to the TPS CR.G3 antenna, the relative vertical offset for the LEI AT504 antenna is −8.4 mm, the offset for the ASH701945C_M antenna is 5.5 mm, and those for the ASH700936E_C and ASH701945B_M antennas are approximately between −2 mm and −3 mm. The relative offsets for the same type of antennas are approximately 1 mm. By correcting the absolute PCVs, the existing relative offset becomes negligible for horizontal positioning.

Description: Publication date: Available online 28 August 2015 Source: Geodesy and Geodynamics Author(s): Guiju Wu, Hongbo Tan, Guangliang Yang, Chongyang Shen In this study, we analyzed the gravity and, magnetic characteristics, and the occurrence of a fault zone and discussed the relationships between the two locations. The results reveal that the subsurface structures strikes are different compared with those in the research region. In other words, the geophysical advantageous directions from the gravity and magnetic anomalies are not the same as those caused by the surface structures. The local horizontal gradient results from the gravity and magnetic anomalies show that the majority of earthquakes occur along an intense fault zone, which is a zone of abrupt gravity and negative magnetic change, where the shapes match very well. From the distribution of earthquakes in this area, we find that it has experienced more than 11 earthquake events with magnitude larger than M s7.0. In addition, water development sites such as Jinshajiang, Lancangjiang, and the Red River and Pearl River watersheds have been hit ten times by earthquakes of this magnitude. It is observed that strong earthquakes occur frequently in the Holocene active fault zone.

Description: Publication date: Available online 28 August 2015 Source: Geodesy and Geodynamics Author(s): Zhou Hao, Luo Zhicai, Zhong Bo A new temporal gravity field model called WHU-Grace01s solely recovered from Gravity Recovery and Climate Experiment (GRACE) K-Band Range Rate (KBRR) data based on dynamic integral approach is presented in this paper. After meticulously preprocessing of the GRACE KBRR data, the root mean square of its post residuals is about 0.2 micrometers per second, and seventy-two monthly temporal solutions truncated to degree and order 60 are computed for the period from January 2003 to December 2008. After applying the combination filter in WHU-Grace01s, the global temporal signals show obvious periodical change rules in the large-scale river basins. In terms of the degree variance, our solution is smaller at high degrees, and shows a good consistency at the rest of degrees with the Release 05 models from Center for Space Research (CSR), GeoForschungsZentrum Potsdam (GFZ) and Jet Propulsion Laboratory (JPL). Compared with other published models in terms of equivalent water height distribution, our solution is consistent with those published by CSR, GFZ, JPL, Delft institute of Earth Observation and Space system (DEOS), Tongji University (Tongji), Institute of Theoretical Geodesy (ITG), Astronomical Institute in University of Bern (AIUB) and Groupe de Recherche de Geodesie Spatiale (GRGS), which indicates that the accuracy of WHU-Grace01s has a good consistency with the previously published GRACE solutions.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Frank Joseph Wambura, Preksedis Marco Ndomba, Victor Kongo, Siza Donald Tumbo Study Region The Wami River sub-basin is among the river sub-basins with a vital ecosystem in Tanzania. It comprises the Saadani National park and it has the very great potential of irrigation and rain fed agriculture. Study Focus The objective of this study was to evaluate the uncertainty of future streamflow in respect of increasing water demands and uncertain projected climate inputs, General Circulation Models (GCMs). The water demands were projected to the year 2039 and GCM precipitation was selected as the changing climatic variable. The CMIP5-GCMs were evaluated for their skills and those with the minimum skill scores above 75% were downscaled and used in projection of scenario RCP 8.5 precipitation. Then uncertainties of RCP 8.5 precipitation were estimated using a fuzzy extension principle and finally used to simulate uncertainties of future runoff using a rainfall-runoff model, Soil and Water Assessment Tool (SWAT). New Hydrological Insights for the Region The results of projected streamflow shows that the baseline annual climatology flow (ACF) is 98 m 3 /s and for the future, the median ACF is projected to be 81 m 3 /s. At 100% uncertainty of skilled projections, the ACF from the sub-basin is projected to range between −47% and +36% from the baseline ACF. However, the midstream of the sub-basin shows reliable water availability for foreseen water uses expansion up to the year 2039.

Description: Publication date: Available online 29 July 2015 Source: Journal of Rock Mechanics and Geotechnical Engineering Author(s): E.T. Brown