Numerical simulation of sediment deposition thickness at Beidaihe International Yacht Club

The finite element method （FEM） was used to simulate sediment hydrodynamics at the Beidaihe International Yacht Club, and a two-dimensional model was established. The sediment movement and deposition were analyzed under many tidal conditions in conjunction with the hydrological regime of the Daihe River. The peak value of the sediment deposition thickness appears in the main channel and around the estuary. The sediment deposition thickness is essentially constant and relatively small in the project area. The sediment deposition thickness in the main channel, in the yachting area, and around the hotel is greater than the other areas in the project. Regular excavation and dredging of the channel is the best measure for mitigating the sedimentation.

Magnetic Applications to Subsurface and Groundwater Investigations: A Case Study from Wadi El Assiuti, Egypt

Wadi El Assiuti represents a promising area for agricultural development and building new communities far from the overpopulated areas in the Nile Val-ley. An integrated approach of satellite-based data and geophysical data with borehole data was used for defining the area of interest, the sediment thick-ness, delineating the subsurface structures, and mapping the depth to the basement rocks, and defining the groundwater aquifers. Findings are: 1) Dramatic changes are detected in the anthropogenic activities at the entrance area of the wadi, making stress and heavy exploitation of the groundwater resources. However, the central and northeastern regions show no development;2) Several structural trends in the directions of NNW, NW, NE, and E-W are cutting the basement rocks and sedimentary cover;3) The depth to the basement rocks is increasing eastward from ~2.24 km to ~4.84 km;4) Three groundwater-bearing reservoirs are represented by the shallow Qua-ternary, the fractured limestone, and the deep Nubian sandstone aquifers;5) The deep-seated faults are affecting the area and rising groundwater from the deeper Nubian aquifer along its sub-vertical trend;and 6) The results are in-formative and used to define the suitable sites for water well drilling.

Comprehensive Analysis and Artificial Intelligent Simulation of Land Subsidence of Beijing, China

Mechanism and modeling of the land subsidence are complex because of the complicate geological background in Beijing, China. This paper analyzed the spatial relationship between land subsidence and three factors, including the change of groundwater level, the thickness of compressible sediments and the building area by using remote sensing and GIS tools in the upper-middle part of alluvial-proluvial plain fan of the Chaobai River in Beijing. Based on the spatial analysis of the land subsidence and three factors, there exist significant non-linear relationship between the vertical displacement and three factors. The Back Propagation Neural Network (BPN) model combined with Genetic Algorithm (GA) was used to simulate regional distribution of the land subsidence. Results showed that at field scale, the groundwater level and land subsidence showed a significant linear relationship. However, at regional scale, the spatial distribution of groundwater depletion funnel did not overlap with the land subsidence funnel. As to the factor of compressible strata, the places with the biggest compressible strata thickness did not have the largest vertical displacement. The distributions of building area and land subsidence have no obvious spatial relationships. The BPN-GA model simulation results illustrated that the accuracy of the trained model during fifty years is acceptable with an error of 51% of verification data less than 20 mm and the average of the absolute error about 32 mm. The BPN model could be utilized to simulate the general distribution of land subsidence in the study area. Overall, this work contributes to better understand the complex relationship between the land subsidence and three influencing factors. And the distribution of the land subsidence can be simulated by the trained BPN-GA model with the limited available dada and acceptable accuracy.

Combined Moho Parameters Determination Using CRUST1.0 and Vening Meinesz-Moritz Model

According to Vening Meinesz-Moritz （VMM） global inverse isostatic problem, either the Moho density contrast （crust-mantle density contrast） or the Moho geometry can be estimated by solv- ing a non-linear Fredholm integral equation of the first kind. Here solutions to the two Moho parame- ters are presented by combining the global geopotential model （GOCO-03S）, topography （DTM2006） and a seismic crust model, the latter being the recent digital global crustal model （CRUST1.0） with a resolution of 1°×1°. The numerical results show that the estimated Moho density contrast varies from 21 to 637 kg/m3, with a global average of 321 kg/m^3, and the estimated Moho depth varies from 6 to 86 km with a global average of 24 km. Comparing the Moho density contrasts estimated using our least-squares method and those derived by the CRUST1.0, CRUST2.0, and PREM models shows that our estimate agrees fairly well with CRUST1.0 model and rather poor with other models. The estimated Moho depths by our least-squares method and the CRUST1.0 model agree to 4.8 km in RMS and with the GEMMA1.0 based model to 6.3 km.