بررسي پديده ي فرونشست در دشت سلماس با استفاده از روش اينترفرومتري و مشاهدات ژئودتيك

Subsidence Detection in Salmas Area Using InSAR and Geodetic Techniques

The subsidence of the Earth surface is a phenomenon that occurs in some places in the Iran which caused by extraction of underground sources of water. The Interferometric Synthetic Aperture (InSAR) technique provides an effective tool to detect and measure the magnitude and spatial variation of the earth surface displacement ) such as subsidence especially when it is combined with geodetic techniques. Repeated levelling and permanent GPS measurement shows that there is subsidence in Salmas area with rate, about 6 cm/year. We used ENVISAT and ALOS radar images, the subsidence for GGSH permanent GPS station determined in 2005, 2007 (during 105 days) and 2009. The subsidence rate determined by InSAR has a good consistency with h-component of GPS time series. The subsidence map for Salmas area computed for 2009. This map shows that maximum subsidence occurs in middle W of Salmas plain and the rate of subsidence .9 increased during 2009 to 11 cm/year.