Volcano number:263040
Geodetic measurements?Yes
Deformation observation?Yes
Measurement method(s):InSAR
Duration of observation:2007-2008
Inferred cause of deformation:Hydrothermal
Characteristics of deformation:

While the survey was not focused on this volcano, Perbakti-Gagak was included in the 2007-2008 InSAR study of the island of Java performed by Philibosian & Simons. Using interferometric PALSAR data, the study noticed a widespread, locally heterogeneous subsidence signal of just over 5cm associated with Perbakti-Gagak, which the authors deemed most likely to be linked to a hydrothermal cause; there has been significant phreatic activity at this location in the past, and the site is used for fluid extraction for the purposes of geothermal power.

Reference:Philibosian, B. and Simons, M. 2011. A survey of volcanic deformation on Java using ALOS PALSAR interferometric time series. Geochemistry, Geophysics, Geosystems, 12 (11). DOI: 10.1029/2011GC003775
Location:106.7, -6.75

Photo from Smithsonian Institution Global Volcanism Program: Perbakti-Gagak. 1989.

Deformation of Perbakti-Gagak. (a) Sum of all time steps (dates are in YYYYMMDD format) for track 438. Box shows area of Figure 14b; black circle shows location of Perbakti-Gagak volcano. (b) Detail of Perbakti-Gagak area; black circle centered on time series point. (c) Time series of Perbakti-Gagak showing ∼5 cm/yr LOS change consistent with subsidence. (Philibosian & Simons, 2011).