Magma chamber deflation recorded by the global positioning system: The Hekla 1991 Eruption

Between January 17 and March 11, 1991, 0.15 km3 of lava erupted initially from several radial fissures and subsequently from a single fissure on the SE flank of Hekla volcano, Iceland. Hekla is surrounded by an array of control points measured in 1989 using GPS geodesy and re‐measured after the eruption. These measurements indicate that the eruption was associated with a surface deflation volume of centered on Hekla . The depth to the magma reservoir is km, poorly constrained due to the absence of GPS control points close to the volcano.