Post-Eruption Deformation Processes Measured Using ALOS-1 and UAVSAR InSAR at Pacaya Volcano, Guatemala

Abstract

Pacaya volcano is a persistently active basaltic cone complex located in the Central American Volcanic Arc in Guatemala. In May of 2010, violent Volcanic Explosivity Index-3 (VEI-3) eruptions caused significant topographic changes to the edifice, including a linear collapse feature 600 m long originating from the summit, the dispersion of~20 cm of tephra and ash on the cone, the emplacement of a 5.4 km long lava flow, and~3 m of co-eruptive movement of the southwest flank. For this study, Interferometric Synthetic Aperture Radar (InSAR) images (interferograms) processed from both spaceborne Advanced Land Observing Satellite-1 (ALOS-1) and aerial Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) data acquired between 31 May 2010 and 10 April 2014 were used to measure post-eruptive deformation events. Interferograms suggest three distinct deformation processes after the May 2010 eruptions, including: (1) subsidence of the area involved in the co-eruptive slope movement; (2) localized deformation near the summit; and (3) emplacement and subsequent subsidence of about a 5.4 km lava flow. The detection of several different geophysical signals emphasizes the utility of measuring volcanic deformation using remote sensing techniques with broad spatial coverage. Additionally, the high spatial resolution of UAVSAR has proven to be an excellent compliment to satellite data, particularly for constraining motion components. Measuring the rapid initiation and cessation of flank instability, followed by stabilization and subsequent influence on eruptive features, provides a rare glimpse into volcanic slope stability processes. Observing these and other deformation events contributes both to hazard assessment at Pacaya and to the study of the stability of stratovolcanoes.

Three‐dimensional displacements of a large volcano flank movement during the May 2010 eruptions at Pacaya Volcano, Guatemala

“…Amplitude pixel offset tracking increased measurement recovery by 48%, or an area increase of ~1.29 km 2 , over classic InSAR techniques (Figure b), confirming that parts of the upper edifice were involved in the slope movement. Although pixel offset tracking cannot recover deformation on the upper southwest flanks due to severe surface disturbances, based on the smooth deformation field and the spatial extent of settlement posteruption [ Schaefer et al ., ], we speculate that displacements increase toward the summit, similar to the western flank. This is supported by significant deformation (~20 cm) of the ancestral collapse scarp located to the NNW of the linear trough measured with GPS in January of 2009 and 2011.…”

“…Substantial horizontal movement of the SW flank perpendicular to the trough also likely played a role in its formation, although the lack of measurements near the summit prevents us from directly correlating a landslide head scarp to the trough location. However, cracking along this NNW trend and the eruption of a large lava flow on the SE flank shortly after the explosive eruptions indicate that a tensional zone spans the entire cone [ Schaefer et al ., ]. The orientation of the magma intrusion and trough formation is likely controlled by the local transtensional (ENE‐WSW σ 3 component) stress regime [ Schaefer et al ., ].…”

“…The absence of long-term deformation prior to (PSI results Figure 3) and after [Schaefer et al, 2016] the slope movement suggests that the landslide was both rapidly triggered and arrested, likely contained to the explosive phases during the 2 day eruption. Magma-induced flank displacement on the order of tens of centimeters has been observed at smaller scales at other volcanoes such as Kilauea [Swanson et al, 1976], Piton de la Fournaise [Sigmundsson et al, 1999], and Etna [Acocella et al, 2003].…”

Mining-Induced Time-Series Deformation Investigation Based on SBAS-InSAR Technique: A Case Study of Drilling Water Solution Rock Salt Mine

“…The new monitoring approach is an important complement to the traditional geodetic surveying methods [12]. D-InSAR is widely applied to detect and monitor earthquake deformation [13], glacial shift [14], volcanic activity [15], and landslides [16], as well as man-made activities such as mining subsidence [17] and urban settlement caused by groundwater overdraft [18]. However, the unavoidable influences of the temporal and spatial decorrelation and atmospheric delay have brought restrictions on its application, especially on mining areas vulnerable to decorrelation.…”

Investigation on Mining Subsidence Based on Multi-Temporal InSAR and Time-Series Analysis of the Small Baseline Subset—Case Study of Working Faces 22201-1/2 in Bu’ertai Mine, Shendong Coalfield, China

“…Differential InSAR (DInSAR), as an extension of InSAR in terms of monitoring ground deformation, is mainly used to capture centimeter-level or smaller ground deformations along the line of sight (LOS) of a radar satellite. Considerable developments related to DInSAR monitoring of earthquake deformation [3,4], volcanic activities [5,6], glacial shift [7,8], urban water-loss settlement [9,10], mining subsidence [11,12], and landslides [13,14] have been achieved. However, DInSAR technology can easily cause interference decorrelation for mining subsidence with immense deformation and short deformation period.…”