Morphological Change in the Northern Red River Delta,Vietnam     

Vuong Van Bui  Daidu Fan  Dac Ve Nguyen  Dinh Lan Tran  Duc Thanh Tran  Van Long Hoang  Thi Hong Hanh Nguyen 《中国海洋大学学报(英文版)》2018,17(6):1272-1280

Coastal erosion has become a worldwide concern, typically in the densely populated Asian mega-river deltas. Severe coastal erosion in the southern Red River Delta(RRD) has been intensively studied. Coastal morphological change in the northern RRD was examined in detail through DEM(Digital Elevation Model) analysis based on time series of bathymetrical maps(1965–2004) and Landsat images(1975–2015) in this study. The results show that the northern RRD is featured by rapid coastal accretion in the past few decades, although suspended sediment flux has dropped by roughly 60% after the completeness of Hoa Binh Dam(HBD) in 1988 and relative sea level rose at 1.9 mm yr~(-1). However, accretion at the outer part of subtidal shoals and platforms was observed to slow down quickly or even turned into erosion in the last two decades. The resuspended sediments from the erosion zone can be transported landward to replenish the inner coastal zone, keeping the latter accretion in the near future to compensate for the sediment discharge decrease from the river. However, this lag effect should be terminated soon if other adverse effects go worse, e.g., damming rivers, sea-level rising, strengthening storms, land reclamation and other poor-designed coastal engineering. Coastal planners and managers should pay full attention to these changes.  相似文献   

Establishing an early warning system for flash floods in Hoang Su Phi District,Ha Giang Province,Vietnam     

Thach Ngoc Nguyen  Canh Xuan Pham  Huy Quoc Nguyen  Toan Ngo Bao Dang 《Singapore journal of tropical geography》2019,40(2):312-333

Hoang Su Phi is a mountainous district in Ha Giang province, Vietnam. When the rainy season arrives in these parts, flash floods (besides landslides), frequently occur in many areas, seriously affecting the socio‐economic condition of the district. Therefore, in this paper, we have developed an early warning system for flash floods, established based on a geomorphological and hydrological approach. The basic principle underlying this system is the fact that flash floods will often occur where there is high potential risk with sufficient rainfall. In the model, eight parameters of the basin were used to build a potential flash flood map. Using the spatial processing module in an open source software, early predictions from automatic weather stations were interpolated and processed online to produce a potential risk map. Depending on the threshold of precipitation values, the results determined locations where flash flood may occur at various flash flood risk indices (FFRI). The system may be applied to support provision of early flash flood warning up to 1?6 days in advance in the district, allowing the local government ample time to make appropriate decisions on the prevention and/or mitigation of damages caused by flash flood hazards.  相似文献   

Prediction of Blast-Induced Ground Vibration Intensity in Open-Pit Mines Using Unmanned Aerial Vehicle and a Novel Intelligence System     

Bui  Xuan-Nam  Choi  Yosoon  Atrushkevich  Victor  Nguyen  Hoang  Tran  Quang-Hieu  Long  Nguyen Quoc  Hoang  Hung-Thang 《Natural Resources Research》2020,29(2):771-790

Natural Resources Research - Predicting and reducing blast-induced ground vibrations is a common concern among engineers and mining enterprises. Dealing with these vibrations is a challenging issue...  相似文献   

A Novel Artificial Intelligence Approach to Predict Blast-Induced Ground Vibration in Open-Pit Mines Based on the Firefly Algorithm and Artificial Neural Network     

Shang  Yonghui  Nguyen  Hoang  Bui  Xuan-Nam  Tran  Quang-Hieu  Moayedi  Hossein 《Natural Resources Research》2020,29(2):723-737

Natural Resources Research - The primary purpose of this study was to develop a novel hybrid artificial intelligence model, with a robust performance, to predict ground vibration induced by bench...  相似文献   

黄土丘陵区雨强对水流含沙量的影响     

刘晓燕  党素珍  刘昌明  董国涛 《地理学报(英文版)》2020,30(3):455-467

To study the effects of changes in the rainfall intensity on sediment concentrations in the Loess Plateau,the observed rainfall intensities and sediment concentrations from three typical small watersheds were used to analyze the relationship between these parameters.The results showed that the sediment concentration generally increased with the increasing rainfall intensity on slope scale.However,at watershed scale,a significant threshold phenomenon was observed for the effects of the rainfall intensity on the sediment concentration.When the rainfall intensity exceeds the threshold,the flood sediment concentration will no longer increase with the increase in the rainfall intensity.The rainfall intensity threshold increased with increasing vegetation coverage.The rainfall intensity threshold was 10–15 mm/h during 1956–1969,reached 20 mm/h from 1990 to 1997 and is approximately 40 mm/h at present.Due to a rainfall intensity of 10–15 mm/h almost happened every year,the vegetation did not change much from the 1950s to 1980s.Sediment yield mainly depends on soil erosion caused by surface flow,but the surface flow speed does not increase indefinitely with the increase in the flow discharge.Thus,the annual maximum sediment concentration of the tributaries in the loess area has been basically stable before the 1990s.  相似文献   

С�������뷽���������Ľ�   总被引：6，自引：2，他引：4  

曲国庆  党亚民  章传银  苏晓庆 《大地测量与地球动力学》2008,28(4):102-106

??С?????????е?????????????????????С???????????????????????????????????????????????????????????飬??????????????????????????????????????????ж??????????????,????????????????????????????  相似文献   

Present-day stress and pore pressure fields in the Cuu Long and Nam Con Son Basins, offshore Vietnam   总被引：1，自引：0，他引：1  

Nguyen Thi Thanh Binh  Tomochika Tokunaga  Hoang Phuoc Son  Mai Van Binh 《Marine and Petroleum Geology》2007,24(10):607-615

Knowledge of the in situ, or contemporary stress field is vital for planning optimum orientations of deviated and horizontal wells, reservoir characterization and a better understanding of geodynamic processes and their effects on basin evolution.This study provides the first documented analysis of in situ stress and pore pressure fields in the sedimentary formations of the Cuu Long and Nam Con Son Basins, offshore Vietnam, based on data from petroleum exploration and production wells.In the Cuu Long Basin, the maximum horizontal stress is mainly oriented in NNW–SSE to N–S in the northern part and central high. In the Nam Con Son Basin, the maximum horizontal stress is mainly oriented in NE–SW in the northern part and to N–S in the central part of the basin.The magnitude of the vertical stress has a gradient of approximately 22.2 MPa/km at 3500 m depth. Minimum horizontal stress magnitude is approximately 61% of the vertical stress magnitude in normally pressured sequences.The effect of pore pressure change on horizontal stress magnitudes was estimated from pore pressure and fracture tests data in depleted zone caused by fluid production, and an average pore pressure–stress coupling ratio (ΔS_h/ΔP_p) obtained was 0.66. The minimum horizontal stress magnitude approaches the vertical stress magnitude in overpressured zones of the Nam Con Son Basin, suggesting that an isotropic or strike-slip faulting stress regime may exist in the deeper overpressured sequences.  相似文献   

The roles of the reversibility and irreversibility of capillary bonds on the impact dynamics of agglomerates     

Vo  Thanh-Trung  Nguyen  Trung-Kien 《Acta Geotechnica》2023,18(1):217-233

Acta Geotechnica - Wet agglomerates such as iron-ores, tablets, and aggregates are omnipresent in multi–field industries. However, our understanding of the impact dynamics of these materials...  相似文献