Fig. 2: Map and tephra deposition pattern at the Northern Escanaba (NESCA) eruption site with theoretical fits.
From: Rapid heat discharge during deep-sea eruptions generates megaplumes and disperses tephra
Sidescan sonar imagery of the Northern Escanaba (NESCA) lava flow at the southern end of the Gorda Ridge (see Fig. 1A). Circles show locations of sediment pushcores taken along four profiles around the flow by15, with the area of the data points proportional to the mass per unit area of tephra in the 250–500 μm range. The extent of the lava flow is indicated by a red outline. The plots on the right show the mass per unit area of the corresponding sampled data profiles (labeled 1–4) as a function of distance from an inferred center marked by the yellow star in the map. The inferred center is the unique position creating a global minimum in mean square error resulting from fitting our Gaussian model given by Eq. (1) to the data. This is ~800 m from the location of the actual eruptive vent, recently identified using high-resolution bathymetric data (D. Clague, pers. comm.) and shown by the black cross. The Gaussian dispersal pattern resulting from our regression analysis is shown as a dashed curve on each of the plots, for which the dispersal scale L ≈ 4.9 km. The 15% error in estimating the mass of glass particles15 corresponds to the approximate size of the circular markers. Concentric circles on the map represent 2-km increments from the calculated center. Sonar imagery from38.
