Havre Volcano: Deep-Sea Currents Sculpt Seafloor Secrets

Recent scientific expeditions have revealed the intricate relationship between deep-ocean currents and the seafloor sediments surrounding Havre Seamount, a significant volcanic feature in the Kermadec arc. These interactions are crucial for understanding sediment transport mechanisms, reconstructing past oceanic environments, guiding resource exploration, and mapping marine ecosystems.

An international research collaboration utilized data from the MESH voyage in 2015 and the VULKA expedition in 2022, conducting high-resolution seafloor observations around Havre Seamount. The analysis identified 433 distinct seafloor bedforms at depths ranging from 794 to 1,662 meters. The findings highlight that deep-sea bedforms are significantly shaped by the dynamic interplay of shifting ocean currents and underlying seafloor topography, with variations occurring across scales from meters to hundreds of meters.

This variability challenges existing sedimentological models, leading to the development of a novel facies model termed Deep-water Multidirectional Tractional Sands (DMTS). Research on areas like the Mozambique continental slope indicates that mixed turbidity-contour current networks are increasingly recognized as major drivers of sediment transport. These complex systems, where turbidity and contour currents intertwine, can alter traditional sediment transport pathways and influence the distribution of materials, including carbon and pollutants, across the seafloor.

The study also emphasizes the critical role of seafloor topography, such as submarine canyons, in directing and interacting with these currents, resulting in localized and intricate sediment transport patterns. The complexity of bottom currents can further complicate modern data collection and the modeling of volcanic events. Understanding these deep-sea sediment dynamics is paramount for accurately reconstructing historical oceanographic conditions, supporting marine resource exploration, and advancing marine conservation initiatives.

The Havre Seamount, part of the Kermadec Volcanic Arc, experienced a major eruption in August 2012, noted as the largest submarine explosive eruption ever recorded. This event, occurring at depths of at least 900 meters, produced a plume that reached the ocean's surface and extended into the atmosphere. The 2015 expedition to Havre, employing advanced underwater robots, aimed to sample rocks and pumice and observe new volcanic rock formations, thereby enhancing the comprehension of these deep-sea volcanic phenomena.