Reconstructing 3100 years of extreme coastal flooding events from Emau Island, Vanuatu

Li, Yanan and Donnelly, Jeffrey and Gao, Shu and Gao, Chujie and Bramante, James J. and Kotra, Krishna K. (2026) Reconstructing 3100 years of extreme coastal flooding events from Emau Island, Vanuatu. Quaternary Science Reviews, 373 . pp. 1-11. ISSN 1873-457X

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Abstract

Tropical cyclones (TCs) are posing growing threat to coastal populations and property, thereby necessitating more millennial paleoclimatic reconstructions. This study presents a 3100-year record from Marou Lagoon, Emau Island, Vanuatu. Using coarse anomalies as the main proxy, 36 intense tropical cyclones are identified (~1.2/ century). Active TC phases occurred during 1550–1750 CE, 350–750 CE, and the 20th century, contrasting with a pre-Common Era quiescent period. Comparative analysis with five paleotempestological records across the tropical South Pacific reveals multidecadal-to-centennial TC variability is dominantly governed by ENSO-driven shifts in the South Pacific Convergence Zone (SPCZ). La Ni˜ na-like periods cause southwestward SPCZ displacement and expansion, causing basin-wide enhanced cyclogenesis, while persistent strong El Ni˜ no conditions collapse the SPCZ into a zonal structure near French Polynesia, concentrating activity at eastern sites and suppressing western ones. Weak-to-moderate El Ni˜ no states exhibit stochastic dominance. Critically, sedimentological analysis reveals the most prominent event bed represents the cataclysmic Kuwae eruption in mid-15th. This deposit exhibits a five-stage sequence reflecting eruption progression, providing unprecedented resolution of eruption dynamics and tsunami impacts that surpass subaerial records. Typical diagnostic features of tsunami deposits (e.g., hummocky cross-stratification) are absent due to lagoon barrier/reef sheltering, and the heterogeneous density and shape of dominant pyroclastic materials (especially pumice) invalidate standard hydraulic grain-size models. This study demonstrates that sheltered lagoons preserve high-fidelity records of both extreme TCs and volcanogenic tsunamis. Such archives offer critical insights into regional climatic drivers and geohazard mechanisms but require environment-specific sedimentological frameworks, particularly where low-density pyroclastics dominate coarse fractions.

Item Type:	Journal Article
Uncontrolled Keywords:	Tropical cyclones, Tsunami, Reconstruction, South Pacific convergence zone, ENSO, Kuwae volcano
Subjects:	Q Science > Q Science (General) Q Science > Q Science (General) > Q1-295 General
Divisions:	Faculty of Science, Technology and Environment (FSTE) > School of Biological and Chemical Sciences
Depositing User:	Krishna Kotra
Date Deposited:	08 Dec 2025 23:01
Last Modified:	08 Dec 2025 23:01
URI:	https://repository.usp.ac.fj/id/eprint/15223

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