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Ha Tinh is one of the provinces most affected by natural hazards, especially flash floods. Sloping hilly terrain conditions, reduced covering density of forest and unfavorable weather conditions are potential hazards to flash floods. Flash floods potential area mapping at Huong Khe district, Ha Tinh province was carried out using Remote Sensing and GIS technologies. Factors causing flash floods was indentified and classified basing n their afecting level. Component maps of flash flood–causing factors were overlayed. Factors causing flash floods as noted by Greg Smith included: slope, soil type, forms of using land, covering density of forest. Potential areas of flash floods and the potential level of each part were indentified. The resulted maps can be used for forecasting risk regions of flash floods at the district.

By 5 main methods including data collections and compilations, field surveys, similarity comparison, mapping and GIS, the geomorphological characteristic of notches in Ha Tien – Kien Luong containing morphologies, origins and ages are proved. Those notches had morphologies of U and V and 3 types of origins including chemical solution, mechanical abrasion and bioerosion; notches were formed in stage of Holocene regressive sea. Notches were created at four stopped periods corresponding to four sea level elevations: 5 m, 3 m, 1 m and 0 m (current sea level) respectively had the age of 5.480, 3.180, 1.025 years ago and the current level has being formed. This research had provided a useful scientific literature that includes the essential role of organisms in forming notches, the influences of organisms, waves and shielding rate on morphologies, and evidence of climate change in the past. By those reasons, people need to calm down, observe, adapt, and respond flexibly to the climate change instead of constructing costly structures. Coastal notches are important marine geological heritage so the conservation of those coastal notches were necessary for research and education, prediction of the sensitive Ha Tien – Kien Luong region, contribution towards risks of planning and construction in areas of underground limestone caves.

Binh Thuan coastal zone, nearly 192,9 km shoreline, is well known for residential, recreational areas and minor industries. Shoreline is vulnerable to accelerated sea level rise (SLR) due to its low topography and its high ecological. The present study has been carried out with a view to assess the coastal vulnerability of SLR. Coastal vulnerability map has been built to the calculating results of the place vulnerability index (PVI). The PVI is derived by summing the CVI (coastal vulnerability index) and CSoVl (coastal social vulnerability index) scores. CVI is calculated from nine variables: Geology, geomorphology, coastal slope(%), shoreline change rate (m/yr), mean elevation (m), shoreline direction, mean tidal range (m), wave height (m) and SLR (mm/yr). We use two socioeconomic variables for CSoVI which are socioeconomic variable and relative distance to coast. Results of the vulnerable areas analysis indicate that 120,73 km2 is at very high vulnerable, 84,96 km2 high, 109,23 km2 moderate, 113,99 km2 low and 232,20 km2 very low. The method in this study which combine CVI, CSoVI and PVI together is new protocol of coastal vulnerability assessment for Vietnam coastal zone due to future SLR.

Geosites in Ha Tien - Kien Luong are classified into different categories of stratigraphy (Paleozoic, Mesozoic, Kainozoic); tectonics and geomorphology (coast, karst, landscape). Values of geosites are estimated by marks (in range from 0 to 1) for each criterion of two value sets: 1) The scientific value (integrity representativeness, rareness, paleogeographic value and complexity); and 2) The additional value (ecological, aesthetic, cultural and economic value). The study showed that geosites with high scientific value are Minh Hoa, Bai Nam (Hon Nghe island), Thach Dong, Hon Chong. Some of karstic geosites have high cultural value as Thach Dong, Da Dung, Hang Tien, Chua Hang, Mo So. The dominant value for aesthetics belongs to geosites of Hon Nghe, Mui Nai, Hon Chong. Phu My plain is attracted by ecological value and Mui Hon Trem has high mark of economic value. Two maps were created for displaying geosites of the study area. The first one represents “scientific values” of geosites. The second map represents the scientific and the dominantly additional values by proportional circles.

Geodiversity may be defined as the range or diversity of geological (rocks, minerals, fossils), geomorphological (landforms and processes) and soil features, including their assemblages, properties, interpretations and systems. Hatien-Kienluong area contains some of the most important and diverse geological and geomorphological features. There exists the oldest sedimentary formation in the South of Vietnam, almost all types of rocks, various landforms and mineral resources, particularly building materials. Many landscapes here were acknowledged as national beauty spots, for instance, Hon Chong mount, Thach Dong and Da Dung mount. However, we have neither a comprehensive evaluation nor an appropriate conservation and management of geodiversity of this area that leads to degradation and destruction of many geosites by natural impacts and human economic development activities. Therefore, an integrated approach to conserve geodiversity is necessary for sustainable development that ensures the benefit of both present and future generations.

Can Gio coastal zone is composed of funnel – shaped estuaries (Soai Rap, Dong Tranh, Long Tau) and coastal line from Dong Hoa headland to Can Gio headland. Dominant dynamic geomorphic process in study area is coastal erosion by tides and waves. In the study, the using associative methods: collection of data, analysis of satellite imageries, GIS and field work is to detect and identify levels of coastal erosion. Results of this research have indicated that erosion process in study area has been taking place during several decades with moderate rate 5 – 12m/year and even 22m/year in sensitive segments. Especially, the sand dune from Dong Hoa headland to Can Gio headland, Long Tau estuary and the Eastern shore of Thanh An Island are seriously eroded. Coastal erosion in Can Gio, Viet Nam as well as throughout the world is relative to sea level rise happening gradually. Anthropogenic activities such as: Buildings of hydroelectric dams, exploitation of sand are the other factors have accelerated erosion in the area.