On January 29 and 30, a network of data-collecting stations placed along the flanks of Kilauea Volcano in Hawaii went on the move. Eight hours before Hawaii's most active volcano erupted, a new rift on the volcano's south flank opened and expanded 20 cm, spewing fountains of lava from a series of cracks more than a mile long. The stations, placed along the flanks of the volcano by a team of scientists from Stanford University and the U.S. Geological Survey's Hawaiian Volcano Observatory, consisted of markers anchored in the rock and antennae taking readings from Global Positioning System (GPS) satellites to precisely calibrate each marker location