| Author | Nguyen Thi Tam |
| Call Number | AIT Thesis no.GE-07-13 |
| Subject(s) | Subsidences (Earth movements)--Geographic information systems--Vietnam--Hanoi
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| Note | A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geotechnical and Geo environmental Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-07-13 |
| Abstract | Hanoi is located in the Red River delta, about 100km from the East Sea. The city's population is 3 million and most of water supply comes from groundwater (Giao, 1999). Groundwater exploitation in Hanoi by both public and private wells may have reached 750,000m³/d and the groundwater level has lowered in many locations, say to 35m at Ha Qinh station (Ha, 2007). Over-abstraction of groundwater has caused land subsidence, which in turn affects the upper infrastructures of the city. As the network of monitoring station in Hanoi is still limited, a new tool that can monitor land subsidence over a larger area is needed to be studied. This study has reviewed on a technique known as Satellite-based Interferometric Synthetic Aperture Radar (InSAR) for monitoring land subsidence. Differential InSAR (DInSAR) is a conventional InSAR method, which removes the phase signal caused by relief to yield a differential interferogram in which the signature of surface deformation (in: turn land settlement) can be detected. Raucoules and Carnec (1999) had generated differential interferograms from ERS-1/2 SAR data and detected signatures of ground vertical movement as much as 15 mm within the time period of 2,5 years; Van Anh (2005) had used JERS-1 SAR data in the period of 1995-1998 and detected the settlement rate in the range of 27-33mm/y. The comparison of DInSAR results with the land subsidence records by leveling shows that the settlement from DInSAR was higher than the leveling measurements and the spatial pattern distribution of high settlement rate between them was quite different. In addition, this study has proposed a GIS-based procedure to create a land subsidence susceptibility map for Hanoi, which is resulted from overlaying of 7 layers, i.e., surface settlement, Quaternary formation thickness, groundwater drawdown, groundwater dynamic regime, soft clay distribution, population density, and distribution of industrial areas. A weighted scale from 1 to 5 was proposed and assigned to each layer. The suitability map is classified into four susceptibility zones of occurring land subsidence: the very high susceptibility zone is in the centre of southern Hanoi area; the high susceptibility zone is in the southwestern Hanoi area, the medium susceptibility zone is in the middle of south¬north Hanoi area; and the low susceptibility zone is in the northern Hanoi area |
| Year | 2008 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-07-13 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Giao, Pham Huy; |
| Examination Committee(s) | Meer, Freek van Der;Noppadol Phien-wej; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2007 |