SPATIOTEMPORAL EVOLUTION ANALYSIS OF LAND SUBSIDENCE IN FUZHOU CITY UNDER THE INFLUENCE OF COMPLEX FACTORS

Land subsidence is one of the major geological disasters in Fuzhou, south China. The land subsidence in Fuzhou was discovered by ground monitoring in the mid-20th century. This paper uses the persistent scatterer interferometry(IPTA) to process the time series TerraSAR-X data from 2008 to 2014, and obtains the time series deformation in Fuzhou during this period, the history of urban land subsidence, the status of construction and the abnormal distribution of land subsidence in the study area. Then the spatiotemporal evolution of land subsidence is analyzed under the influence of these complex factors in Fuzhou City. The results suggest that the land subsidence is about 15mm·a^-1 in Fuzhou. There are many obvious rapid subsidence areas. The rapid subsidence area on the ground presents a new feature of space transfer. The subsidence center is transferred from the geothermal hot spring area to the engineering-intensive construction area comparing to the monitoring data from 1960s to 1990s. The large settlement area is dominated by rapid linear settlement. The variation of land subsidence characteristics is affected by the superposition of various complex factors, resulting in expansion of land subsidence space and increased subsidence rate. The research results can provide certain scientific basis and reference for land subsidence risk assessment and land subsidence prevention and control in Fuzhou or other coastal cities.