ROV SuBastian Dive 085- West Mata Summit – FK1711110 – Underwater Fire (Dive 1)
Location: Over West Mata Volcano in the Northern waters of the Kingdom of Tonga
Depth: From 1,400 m
Work Completed: A survey of 2.2 km long geotransect off the West Mata Summit between 1,200 – 1,400 m depth. Investigated several features that showed up as anomalies in previous mapping surveys. Some rock and push core samples taken and the team noted locations of vents for future dives.
ROV SuBastian Dive 086- West Mata Summit – FK1711110 – Underwater Fire (Dive 2)
Location:West Mata Volcano in the Northern waters of the Kingdom of Tonga
Depth: From 1,920 m
Work Completed: A 1.8 km long sinuous geo-transect of the lava formation NE of the West Mata Summit, seeking a feature that showed up as depth anomaly in between 2016 and 2017. The ROV moved upslope from 1,920 m to 1,485 m on a new lava flow and then in older terrain with interesting “Pillow Pox” formations. Opportunistic rock and push core samples taken.
ROV SuBastian Dive 087- West Mata Summit – FK171110 – Underwater Fire (Dive 3)
Location: West Mata Summit, off Tonga
Depth: From 1,643 m
Work Completed: A 1.9 km long geo-transect upslope from the shallow part of the south rift to depths between 1,643 m and 1,230 m. The science team collected lava and sediment samples with more intensive sampling of fluids and biology.
ROV SuBastian Dive 088 – West Mata NE Base “The Muffin” – FK171110 – Underwater Fire (Dive 4)
Location: NE base of West Mata, off Tonga
Depth: From 2700m
Work Completed: A transect across uplifted mound of sediment (“the muffin”) and young lava flows surrounding it at the NE base of West Mata. The science team sampled old and new lavas, and took opportunistic rock and push core samples, testing sediment scoop bags.
ROV SuBastian Dive 089 – Mata Ua – FK171110 – Underwater Fire (Dive 5)
Location: Mata Ua Volcano off Tonga
Depth: From 2400m
Work Completed: Beginning at a black smoker fled, this is a two part dive had a 1.3 km long track to survey/circumnavigate a previously studied vent field, taking rock, sulfide, water and biological samples. Lava samples were also collected to make observations on a geotransect to the summit.
SuBastian Dive 090- Mata Fitu – FK171110 – Underwater Fire (Dive 6)
Date: Dec 1, 2017
Location: Mata Fitu volcano, the northern-most of the North Mata group
Depth: Between 2,385m to 2,535m
Work Completed: This area of the seamount had not been visited before, so this was an exploratory dive, investigating where the MAPR sensors on AUV Sentry saw anomalies on Leg one of this expedition. Opportunistic rock sampling and fluids collected.
SuBastian Dive 091- Mata Tolu West Rift – FK171110 Underwater Fire (Dive 7)
Location: Mata Tolu West Rift, off Tonga
Depth: From 2360m depth
Work Completed: Sampling lavas and making observations on a geotransect along a 1.4 km long track on the west rift to the summit. Surveyed a previously studied vent field, taking rock, sulfide, water, and biological samples.
ROV SuBastian Dive 092- Dacite Flow – FK171110 Underwater Fire (Dive 8)
Location: The only dive outside of the Mata Seamounts: This dive is a geo-transect across Large Dacite Lava Flow on the seafloor located 19 km SW of West Mata summit, off Tonga
Depth: Mostly 2400-2550m
Work Completed: Sampling lavas and making visual observations from a large lava pond to a series of hills located to the west. The science team hopes to determine if the western hills are part of the eruption of this flow and source of the dacite lava flow.
ROV SuBastian Dive 093 – West Mata – NE Pillow Ridge – FK171110 Underwater Fire (Dive 9)
Depth: The starting depth is 2587m and will end at 2365m
Location: This dive was be two separate geo-transects: one shorter one up an older ridge NE of West Mata volcano, and a second longer transect up a young ridge of pillow lavas on the NE flank of West Mata volcano.
Work Completed: The main objectives are sampling both old and new lavas (and sediments) while making visual observations.
ROV SuBastian Dive 094 – Mata Tolu – FK171110 Underwater Fire (Dive 10)
Depth: The starting depth is 2150 m and will end at 1800m
Location: This dive will start at the West Rift and then move north towards the Summit.
Work Completed: The main objectives are taking observations and lava and water samples.
ROV SuBastian Dive 095 – West Mata SW Base – FK171110 Underwater Fire (Dive 11)
Depth: Approximately 3000m
Location: Traveling to West Mata’s SW Rift Zone, the deepest eruption site on West Mata that we know of, but we don’t expect any hydrothermal venting.
Work Completed: The dive will sample lavas and sediments in two areas
ROV SuBastian Dive 096- Mata Fa – FK171110 Underwater Fire (Dive 12)
Depth: The starting depth is 2150m and ending at 1800m
Location: A geo-transect across the summit of Mata Fa volcano, one of the North Mata group of volcanoes. The dive starts on the west rift zone of Mata Fa, which is made of two separate ridges, one higher than the other. It starts on the lower ridge then jumps to the higher ridge before proceeding towards the summit. Afterwards the ROV will drive down the east rift zone.
Work Completed: There have been no camera tows here, so the dive will be a very exploratory.The dive track is designed for viewing and sampling the main constructional morphologic features around the summit
ROV SuBastian Dive 097 – Mata Fitu vent site – FK171110 Underwater Fire (Dive 12)
Depth: Approximately 2700m
Location: The known hydrothermal vent field at Mata Fitu volcano, one of the North Mata group of volcanoes. This is the second dive of this expedition at Mata Fitu, but first visit to the hydrothermal vent field.
Work Completed: The dive starts downslope of the area of known venting and traverses back-and-forth upslope to establish the aerial extent of venting. The dive is a mix of geo-transects to visually explore the area, sample lavas and sediments, and also chemical and biological sampling at the hydrothermal vents.
ROV SuBastian Dive 098 – South Tafu Eruption – FK171110 Underwater Fire (Dive 14)
Depth: The starting depth is ~2100m and ends at ~1600m
Location: Visiting a young volcanic deposit that was emplaced sometime after 2010.
Work Completed: View and sample young basalt lava and pyroclasts. Opportunistic sampling of vent fluids or biota.
ROV SuBastian Dive 099 – North Tafu Eruption – FK171110 Underwater Fire (Dive 15)
Depth: Approximately 2000m to 1400m
Location: Two young eruption sites, one constrained by before-and-after bathymetric surveys between 2010-2017, and the other between 2006-2009
Work Completed: View and sample young basalt lava and pyroclasts, along with opportunistic sampling vent fluids or biota
ROV SuBastian Dive 100 – Mata Ua NE Flank & Vents – FK171110 Underwater Fire (Dive 15 )
Depth: The starting depth is ~2100m and ends at ~1600m
Location: Flank sites on the Northeast flank of Mata Ua. We will then traverse over the venting site, exploring along the way an additional 0.6 km of track.
Work Completed: 100th dive ceremony near vents. Explore for unknown vents several hundred meters NE of known vent sites, looking for additional chimneys as we move into the “Temple of Smoke” area. Observe and sample vent fluids, chimneys, and biota.
ROV SuBastian Dive 101 – Mata Ono – FK171110 Underwater Fire (Dive 17)
Depth: Dive starts on a constructional cone on the west flank, then ascend along a ridge and traverse the south flank at ~2500m for geological observations.
Location: First cone mentioned above, then constructional cone on the east flank, then ascends the east ridge up to the summit
Work Completed: Exploration – search for a vent site during the latter part of the dive, particularly on the traverse up the east ridge toward the summit. Opportunistic sampling vent fluids or biota.
ROV SuBastian Dive 102 – Mata Ono – FK171110 Underwater Fire (Dive 18 )
Depth: Up to 2,525m
Location: Second dive on Mata Ono volcano. The dive starts on a constructional cone on the west flank, then ascend along a ridge and traverse the west and north flanks. Then visit a constructional cone on the east flank and from there, ascend the west ridge upslope a bit.
Work Completed: Ran a series of lines traversing the west and north face of the cone looking at chimney structures and identifying sampling sites. Sampling will commenced once the field was evaluated and defined.
ROV SuBastian Dive 103 – West Mata Upper East Rift – FK171110 Underwater Fire (Dive 19)
Depth: 1600m – 1300m
Location: The dive starts at the 2016-2017 eruption site about 1.5 km NE of the summit, then visits two 2012-2016 eruptions sites further upslope.
Work Completed: Geo-traverse to sample lavas and sediments on three recent eruption sites. A secondary goal to sample fluids and biology late in the dive at the southern of the two 2012-2016 eruption sites, just east of the summit.
ROV SuBastian Dive 104 – Mata Taha – FK171110 Underwater Fire (Dive 20 )
Depth: ~2300m to ~2100m
Location: First ROV dive on Mata Taha volcano, another one of the North Mata Group of volcanoes.
Work Completed: Geo-traverse starting on the north flanks and visit several constructional cones on the way up to the summit. The main goal is rock and sediment sampling, but there is also a weak hydrothermal plume over Mata Taha. Sample fluids and biology any hydrothermal vent sites encountered.
ROV SuBastian Dive 105 – Northern Dacite Flow – FK171110 Underwater Fire (Dive 21)
Location: Deep dacite lava flow adjacent to the North Mata Volcanoes
Work Completed: Objective of dive is examining several different flow areas for lava morphology starting deep and moving shallower, including a traverse up a nearly 100m high escarpment that forms the edge of what looks like a lava drainout structure. The main goal is rock and sediment sampling.