Figure 7

Temporal and spatial influence of great-earthquake cycles on coral reefs along the Sunda megathrust. (a) Schematic summary of earthquake cycles and coral reef response over the last seven centuries. Maximum coseismic uplift values are in red (± 2σ) and interseismic subsidence rates are in blue (in mm/y, ± 2σ); dotted lines are inferred. Color-coded bars show schematic three-phase reef response to culminating earthquakes and interseismic subsidence (orange bars indicate nominal 30 year windows for full post-earthquake reef recovery). The Nias-Simeulue example is a composite microatoll elevation record for Simeulue²⁴ (Bunon village, 1311–1576 CE) and northern Nias²⁵ (sites AFL, MZL, PWG; 1800–1861 CE, 1960–2000 CE). Batu Islands is a composite for south Tanabala island showing a rare locality with long-term tectonic stability^60,63. Mentawai Islands shows strong earthquake cycles at Bulasat, South Pagai island²². (b) Spatial distribution of crustal ruptures for recent large earthquakes (> M_w 7) along the Sunda megathrust since 2000 CE. Red circles indicate estimated rupture areas. Blue letters show the approximate locations of the earthquake cycle time-series for Nias-Simeulue (N, S), Batu Islands (B) and the Mentawai Islands (M). Map is adapted from Natawidjaja et al.²³ with rupture areas and magnitudes from Briggs et al.², Chlieh et al.⁸⁵, Konca et al.⁸⁶, Meltzner et al.⁶², Hill et al.⁸⁷, and references therein.