## 4 InSAR Observations
Interferograms measure a maximum of \(\sim\)25 cm of deflation between 31 May 2010 and 16 July 2010 (Figure 4a), which reduces in magnitude to \(\sim\)10 cm over 682 days between 2011-2013 (Figure 4d). This subsidence differs in magnitude from that measured on the flank, and continues well beyond post-slide settlement, emphasizing a separate source. Several lava flows were deposited to the north of the summit, with selected flows shown in Figure 4e, which cover some of the spatial extent of the deformation described. \begin{table}
\begin{tabular}{l c c|c c c|c c c|c c c c} \hline \hline  & & \multicolumn{4}{c|}{**Acquisition 1**} & \multicolumn{4}{c|}{**Acquisition 2**} & & \\ \hline
**Satellite** & **Flight Direction** & **Look** & & & & & & & & & & & \\
**a** & **a** & **a** & **a** & **a** & **a** & **a** & **a** & **a** & **a** & **a** \\ \hline UAVSAR & 58\({}^{\circ}\)E to 108\({}^{\circ}\  
Figure 3: Slope deformation surrounding the May 2010 eruptions, with the black dashed line marking the outline of the slope instability in panel 3b. (**a**) No deformation of the southwest slope is seen prior to the eruption; (**b**) During the eruptions on the 27 and 28 of May, \(\sim\)3 m of LOS slope displacement can be seen on the southwest sector of the edifice (modified from [22]); (**c**) Immediately after the eruption, subsidence encompasses a similar extent of the southwest flank that moved during the slide; (**d**,**e**) This deformation decreases in magnitude and spatial extent until late December; (**f**) Deformation measured using the first available UAVSAR data after the May 2010 eruption spanning 26 April 2011–8 March 2013 is magnified to show the similarities in the fringe pattern over the southwest flank of the volcano. Similar fringe patterns between this UAVSAR interferogram and the ALOS-1 interferogram in Figure 3c suggests that the deformation observed after the slide is likely dominated by vertical subsidence, as the sensors have nearly opposite looking geometries. A final discernible deformation process is shown in eight interferograms in Figure 5, which depict the emplacement (Figure 5a) and subsequent subsidence (Figure 5b-h) of the 2010 lava flow (outlined in Figure 1b). The interferogram covering the time interval immediately after the eruption (31 May-16 July) additionally contains several ovoid fringes of inflation oriented NNW-SSE near the 2010 lava flow vents (zoomed view, Figure 5a). The fringes, which represent \(\sim\)16 cm of LOS range shortening (corresponding to inflation if the deformation is assumed vertical), extend from the SE slope over the ancestral collapse scrap around 1700-1900 m asl. This area of inflation is directly related to lava flow emplacement, as they are not seen in ALOS-1 interferograms prior to (Figure 3a) or after (Figure 3d) the effusive eruption. The elongated shape suggests a diking event forced magma to the surface, resulting in inflation near the vents. Much of the lava flow becomes coherent in July (Figure 5b), which agrees with CONRED reports of emplacement that state that the flow began on 28 May and ceased movement 33 days on 30 June. Thus, from July 2010 to April 2014, the lava flow shows persistent subsidence that varies in rate but  
Figure 4: Localized deformation to the north of the summit. (**a**) Several fringes to the north of the summit are difficult to discern from subsidence of the southwest flank in the ALOS-1 interferogram immediately after the eruptions on 27 and 28 May; (**b,c**) This signal becomes the only deformation event in subsequent months, reducing in magnitude and spatial extent; (**d**) Fringes are more distinct in a later UAVSAR interferogram, which shows that the area was still subsiding at very slow rates (\(\sim\)10 cm over 682 days) between 2011 and 2013; (**e**) Several recent lava flows (outlined from Landsat satellite images and [20]) have flowed to the north of the summit, the contraction of which could account for some of the measured deformation. decreases over time (Figure 6 and Table 2).