PUBLICATIONS Geophysical Research Letters RESEARCH LETTER Three-dimensional displacements of a large volcano 10.1002/2016GL071402 flank movement during the May 2010 eruptions Key Points: at Pacaya Volcano, Guatemala • Three-dimensional displacements of a volcanic landslide created using pixel L. N. Schaefer1 , T. Wang2 , R. Escobar-Wolf1, T. Oommen1,Z.Lu2, J. Kim2 , offset measurements between two 3 1 synthetic aperture radar amplitude P. R. Lundgren , and G. P. Waite images 1 • Four meters of flank movement at Department of Geological and Mining Engineering and Sciences, Michigan Technological University, Houghton, Michigan, Pacaya Volcano suggest serious USA, 2Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, Texas, USA, 3Jet Propulsion instability hazard Laboratory, California Institute of Technology, Pasadena, California, USA • Episodic movement initiated by rapid triggers may promote volcano edifice instability without timely warning Abstract Although massive flank failure is fairly common in the evolution of volcanoes, measurements of flank movement indicative of instability are rare. Here 3-D displacements from airborne radar amplitude Supporting Information: images derived using an amplitude image pixel offset tracking technique show that the west and southwest • Supporting Information S1 flanks of Pacaya Volcano in Guatemala experienced large (~4 m), discrete landsliding that was ultimately Correspondence to: aborted. Pixel offset tracking improved measurement recovery by nearly 50% over classic interferometric L. N. Schaefer, synthetic aperture radar techniques, providing unique measurements at the event. The 3-D displacement
[email protected] field shows that the flank moved coherently downslope along a complex failure surface involving both rotational and along-slope movement. Notably, the lack of continuous movement of the slide in the years Citation: leading up to the event emphasizes that active movement should not always be expected at volcanoes for Schaefer, L.