Figure 3: Coral-based uplift profile over three timescales on Ranongga and Vella Lavella islands.

(a) Along path AA′ (Fig. 1), with trench to the left, comparison of net mid-Holocene emergence (blue stars; left axis), coseismic uplift pattern during the 2007 M_w 8.1 earthquake (red stars; right axis) and elevations of uplifted, in situ corals sampled (blue circles, sizes decreasing with age; left axis). Locations (blue triangles below) of sampling sites are plotted below along a profile of highest elevation on the islands along AA′; numbers indicate map locations labelled in Fig. 1. All elevation measurements are in metres above living coral (m ALC) except the topography, which is in metres above the mean sea level (ASL). Note: different sized blue circles (in situ coral samples) indicate different ages where sizes decrease with age. (b,c) Comparison of recently killed coral microatolls at Lale (b) and Konggu (c) that reveal vertical motion before the 2007 event along with an illustrative graph of the deformation profiles at their locations on a thousands-of-years timescale (below). The Lale microatoll indicates large pre-2007 submergence (that is, large interseismic subsidence before 2007 event), whereas the Konggu microatoll, ∼10 km north of Lale, shows a marked lack of pre-2007 submergence (that is, suppressed interseismic subsidence before the 2007 event). (d) A typical example of sampled in situ fossil coral with intact, well-preserved morphological characteristics at Konggu. Scale bars, (b) 25 cm, (c) 15 cm, and (d) 20 cm.