Professor Richard Robertson

Description / abstract: Hazardous, volcanic sediment-laden ows called lahars are among the largest sediment ows on Earth, yet their impacts beyond the coastline remain essentially unknown. Although lahars frequently reach the ocean, a lack of offshore observations limits understanding of their contribution to marine sediment budgets, biogeochemical cycling, ecosystem impacts, and hazards to coastal communities and critical infrastructure. Based on the rst offshore observations of ocean-entering lahars, we show that the prevailing conceptual model of direct, short-lived sediment delivery is fundamentally-incomplete. Instead, lahar-derived sediment is transferred offshore through complex, delayed and long-lived process cascades, conveying substantially greater volumes of material to the deep sea than previouslyrecognized, producing widespread damage. A single lahar in a small, normally dry river catchment delivered> 1,600 tonnes of sediment to the ocean in~ 20 minutes, while others damaged subsea telecommunications cables and economically-important sheries. Lahars from a single volcanic island contribute 7% of the annual sediment ux from all ocean islands worldwide, revealing lahars are a dominant and previously-overlooked agent of volcanic sediment delivery to the ocean. As climate change intensi es rainfall, lahar-driven ocean sediment uxes and associated hazards are likely to increase, with far-reaching implications for marine systems and global infrastructure at hundreds of coastal volcanoes worldwide.

Publication/source: EarthArXiv, 2026

Description / abstract: The temporal compositional variation of individual volcanic centres is key to understanding magmatic processes in the underlying crust. La Soufrière volcano, St. Vincent, Lesser Antilles, has erupted predominantly basaltic andesite magmas for hundreds of thousands of years. Sampling of the recently exposed crater walls at La Soufrière reveals that sequentially emplaced crater lavas, feeder dykes, and western flank lavas are low-magnesium basaltic andesites with little variation in major and trace element concentrations, suggesting the system is buffered by the underlying crystal-mush. A single basaltic crater lava unit is more mafic (8 wt. % MgO, 51 – 52 wt. % SiO2) and is compositionally similar to rare low-magnesium basaltic tephra from large explosive eruptions, suggesting more primitive melts are present in the underlying crust but rarely erupt at the surface. New 40Ar/39Ar ages fill a period of previously …

Publication/source: Bulletin of Volcanology 88 (4), 43, 2026

Description / abstract: The compositional variation of individual volcanic centres over time is key to understanding magmatic processes in the underlying crust. La Soufrière volcano, St. Vincent, Lesser Antilles, has erupted predominantly basaltic andesite magmas for hundreds of thousands of years. Sampling of the recently re-exposed crater walls at La Soufrière reveals that sequentially emplaced crater lavas, feeder dykes and lavas on the volcano’s western flank are low-magnesium basaltic andesites with little variation in major and trace element concentrations. A single La Soufrière crater lava unit is more mafic (8 wt.% MgO, 51–52 wt.% SiO2) and is compositionally similar to rare low-magnesium basaltic tephra from large explosive eruptions on St. Vincent, suggesting more primitive melts are present in the underlying crust but rarely reach the surface. New 40Ar/39Ar ages fill in a period of previously undocumented eruptive history …

Publication/source: Goldschmidt 2026 Conference, 2026

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Publication/source: Academic Press, 2026

Description / abstract: The Encyclopedia of Volcanoes, Third Edition, an updated edition of the PROSE award winning title, summarizes our knowledge on volcanoes. The book provides a comprehensive source on the causes of volcanic eruptions with both destructive and beneficial effects. This new edition illustrates the best approaches to characterize key aspects of volcanology, demonstrates the importance of volcanology for a sustainable planet, and was developed by a multidisciplinary, multi-gender, and multi-cultural team of both editors and authors. This is a necessary reference for students, academics, and professionals in volcanology and Earth science to understand and characterize the effects and role played by volcanoes.-Provides a comprehensive reference work on all aspects of volcanology-Explores an integrated transition from the physical process of eruptions through hazards and risk and how volcanoes play a role in global sustainability-Presents hundreds of color photographs, maps, charts, and illustrations, making this an aesthetically appealing reference-Includes a glossary of 3,000 key terms with definitions of all key vocabulary items in the field-Incorporates significantly expanded material on the role of volcanoes in the global cycle, sustainability, and energy