Miniature Autonomous Plume Recorder (MAPR) data acquired at Hunga volcano, Kingdom of Tonga, in July-August 2022 during phase 2 of the Tonga Eruption Seabed Mapping Project (TESMaP-2)

The second phase of the Tonga Eruption Seabed Mapping Project (TESMaP-2) utilized the uncrewed surface vessel (USV) Maxlimer (Sea-Kit International) to conduct remotely-operated surveys of the Hunga volcano seven months after the powerful explosive eruption of 15 January 2022. A custom-built cage and winch with 300 m of non-conducting cable were added to the USV Maxlimer payload to accommodate Miniature Autonomous Plume Recorder (MAPR) instruments, and used to map hydrothermal and volcanic plumes within the crater at Hunga volcano. The MAPR data files are in ASCII comma-delimited format that contains the date/time (UTC), pressure (db), depth (m), temperature (°C), turbidity (optical backscatter, NTU) and oxidation-reduction potential (E, mV) measurements from 29 vertical casts and 8 tow-yo operations that were conducted during TESMaP-2. Methods and results are published in Walker and de Ronde (2024). Unique to this project, this was the first time that standard vertical cast and tow-yo operations were conducted from an uncrewed surface vessel being operated remotely 16,000 km distant from the study site. USV Maxlimer was launched from Nuku'alofa, Kingdom of Tonga and MAPR operations occurred between 27 July 2022 and 29 August 2022. TESMaP-2 was funded by The Nippon Foundation and GEBCO-Seabed2030, with additional support for MAPR operations from NOAA-PMEL Earth-Ocean Interactions program and GNS Science, New Zealand.