What techniques does YVO use to measure ground deformation?
Our primary techniques for measuring ground deformation are GPS and InSAR, defined below. Scientists study ground deformation or movement of the earth’s surface at volcanic sites to help them to determine what could be happening at depth. An injection of magma at depth can move the ground up (inflation) whereas magma draining out of a system, from an eruption or movement elsewhere, can cause the ground to subside (subsidence). Ground movement can be a precursor to magma moving towards the surface but there is evidence of ground movement at many volcanic systems for hundreds to thousands of years without an eruption. There are a variety of techniques that can be used to monitor ground deformation. Early measurements were made by measuring distances with rulers or special measuring sticks to determine vertical ground movements. Electronic distance measurements (EDM – an instrument that both sends and receives an electromagnetic signal) were later used to determine horizontal movements an
