By the use of differential SAR interferometry and permanent scatterer techniques, it is possible to study target movements between SAR acquisitions. For example, it is possible to predict earthquake risk, determine subsidence of cities and even single buildings. Vegetation, however, complicates the use of INSAR techniques, which is a problem in forested areas, such as in Finland. Finnish Geodetic Institute studies the use of INSAR techniques, e.g. for the determination of land uplift patterns.