Figure 4
From: First 3D imaging characterization of Pele’s hair from Kilauea volcano (Hawaii)
Eruption type comparison. (a) Boxplot of the Vesicle Number Density (VND) per melt volume for each eruption type, computed dividing the number of observed vesicles by the volume of the melt phase of each sample. The central red line indicates the median, and the bottom and top edges of the box indicate the 25th and 75th percentiles, respectively. The whiskers extend to the most extreme data points not considered outliers. VND for KI samples shows the highest values, while for HMM the lowest. VND for LOE are in between the previous two; (b) show the Probability Density Function (PDF) computed from the elongation of all the segmented vesicles grouped by eruption type. LOE and HMM samples show a very elongated structure, while PDF for KI samples is almost flat indicating the presence of a mixture of round and very elongated objects (significant differences checked with a one-way Anova test, nKI = 17500, nLOE = 1100, nHMM = 200, p-value < 10−5). Bins are equally spaced in the range determined by the minimum and maximum measured values between the three groups; (c) scatterplot of the elongation as a function of the equivalent spherical diameter of the vesicle. In HMM and LOE Pele’s hair most of the vesicles are strongly stretched. Only few, small and rounded bubbles occur in these two kinds of fragments. The correlation between elongation and size is less evident in KI vesicles.
