Extended Data Figure 5 : Linear resolution analysis.

From: Broad plumes rooted at the base of the Earth's mantle beneath major hotspots

Extended Data Figure 5

Similar to that in Extended Data Fig. 4. This analysis again features whole- and partial-mantle plumes of peak strength −2%, but now of width 600 km (meaning the effective width above 1% anomaly strength is only 300 km). We again find that the synthetic input plumes are recovered quite well, with no evidence of lateral or radial smearing, as well as no gaps in recovery. At the same time, we find that recovered amplitude is poorer than for the larger, 1,000-km-width plumes, in some cases recovering amplitudes of the order of one-quarter of the input, and we note that there is again a slight disparity in amplitude recovery between Hawaii and Iceland. Furthermore, we note that tests using synthetic plumes at or below widths of 600 km push the limits of the spherical-spline lateral basis functions used in our model—particularly in the upper mantle, where the inter-spline absolute distance is larger (although the angular distance remains constant).