While the survey was not focused on this volcano, Perbakti-Gagak was included in the 2007-2008 PALSAR interferometric study of the island of Java performed by Philibosian & Simons. This survey noted significant deformation at the Gede stratovolcano; between 18th September 2007 and 21st December 2008, the east flank of the edifice subsided by approximately 7cm at a steady rate of ~5cm/yr. However, the summit of the volcano appears to have remained roughly stationary during that time period, leading the authors to suggest that the subsidence was due to groundwater extraction. However, as the volcano last erupted in 1957, it is plausible that magma is still present at the site.