The Drivers of Land Use Change in the Migration Area, Three Gorges Project, China: Advances and Prospects

This paper reviewed existing literatures on land use change since the demonstration phase of the Three Gorges Project and found that reservoir inundation, migration resettlement, urban relocation, and post-supporting construction were first paid more attention to, when analyzing the driving forces of land use change in the migration area. However, at the post-migration period （the end of migration resettlement）, above-mentioned drivers had not obviously driven land use change, but the evolutions of ＂migration demands＂ replacing them increasingly became the major drivers of land use change in the migration area. Therefore, the future priority fields of land use explanations in the mi- gration area, Three Gorges Project were （1） identifying the corresponding relationships between the spatial distributions of land use change and migration resettlement and indigenous inhabitants; （2） un- derstanding the change of ＂migration demands＂ and their causing ＂indigenous inhabitants＇ demands＂ being how to drive land use transforms; （3） finding the driving processes of the conflict and exclusion between immigrants and indigenous inhabitants, and the transfer of immigrants and indigenous in- habitants on land use change; and （4） measuring the dynamic feedback of ＂migration demands＂ at dif- ferent stages on the processes, directions and their corresponding impacts of land use change in order to building the coupling framework among ＂migration demands＂, driver behaviors, and land use. This paper presents a new access for the explanation of land use change and also supplies scientific proofs to obtain adaptive decision-making to optimize land use patterns in the migration area, Three Gorges Project.

Temporal variation of gravity field prior to the Ludian Ms6.5 and Kangding Ms6.3 earthquakes

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 Ms6.5 earthquake that occurred on August 3rd, 2014, and the Kangding Ms6.3 earthquake that occurred on November 22 nd, 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 Ms6.3 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 Ms6.5 earthquake.（3） The gravity variation characteristics are reasonably consistent with crustal movements, and deep material migration is likely the primary cause of gravity variation.