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    Abstract:
    The 2012 submarine eruption of Havre volcano in the Kermadec arc, New Zealand, is the largest deep-ocean eruption in history and one of very few recorded submarine eruptions involving rhyolite magma. It was recognized from a gigantic 400-km2 pumice raft seen in satellite imagery, but the complexity of this event was concealed beneath the sea surface. Mapping, observations, and sampling by submersibles have provided an exceptionally high fidelity record of the seafloor products, which included lava sourced from 14 vents at water depths of 900 to 1220 m, and fragmental deposits including giant pumice clasts up to 9 m in diameter. Most (>75%) of the total erupted volume was partitioned into the pumice raft and transported far from the volcano. The geological record on submarine volcanic edifices in volcanic arcs does not faithfully archive eruption size or magma production.
    Keywords:
    Pumice
    Submarine volcano
    Effusive eruption
    Dense-rock equivalent
    Silicic
    Vulcanian eruption
    Peléan eruption
    Seafloor Spreading
    Lateral eruption
    Volcanology
    Monogenetic volcanoes are the most common volcanic landforms on Earth and usually form isolated small-volume volcanic centres with a wide range of eruptive styles and products. Here, I focus on the case of Tseax volcano (Wil Ksi Baxhl Mihl) in north-western British Columbia, Canada's deadliest volcanic eruption; its ~ 1700 CE eruption killed up to 2,000 people of the Nisga'a First Nation. Tseax is composed by two imbricated volcanic edifices (an outer breached spatter rampart and an inner 70 m high tephra cone) and 4 far-travelled, valley-filling lava flows (2 pahoehoe and 2 'a'a) for a total volume of 0.5 km³ submerging the former Nisga'a villages. All the erupted products are Fe-, Ti-rich, basanite-to-trachybasalts and their geochemical homogeneity suggests the eruption of a single magma batch that was produced by low partial melting of a cpx-poor wehrlite at 52 - 66 km depth. The magma was stalled for > 10³ days in the upper crust and cooled down to 1094 - 1087 °C prior to eruption. The eruption lasted between 1 to 4 months and was divided in two main periods. The first period occurred in a typical Hawaiian-style with lava fountaining, spatter activity and the eruption of long pahoehoe flows. Almost half of the total lava volume was erupted in the first days of the eruption with fluxes > 800 m³/s. The lava may have engulfed the Nisga'a villages in a few tens of hours and thus be one of the cause for the fatalities. A vog produced when the lava entered the Nass River may have been also responsible for the Nisga'a deaths. The second period of activity was characterized by low intensity Strombolian explosions with the building of the tephra cone and eruption of the shorter 'a'a lava flows.In high speed channelised lava flows, standing waves are often interpreted as hydraulic jumps, indicating supercritical conditions. Using open channel hydraulic theory for supercritical flows, the geometry of the standing waves to constrain eruption flux and viscosity. I propose that investigating standing waves during ongoing eruption is a powerful tool to help for lava flow modelling and hazard mitigation.
    Lateral eruption
    Dense-rock equivalent
    Effusive eruption
    Phreatic eruption
    Peléan eruption
    Vulcanian eruption
    Magma chamber
    Volcanic cone
    Stratovolcano
    Citations (1)
    Dense-rock equivalent
    Phreatic eruption
    Effusive eruption
    Lateral eruption
    Peléan eruption
    Citations (148)
    Pumice
    Dense-rock equivalent
    Peléan eruption
    Effusive eruption
    Phreatic eruption
    Lateral eruption
    Vulcanian eruption
    Citations (0)
    Abstract Reconstruction of the eruption history of an active volcano is necessary to elucidate its volcanic activity and to assess the probability of its volcanic eruption. Yokodake volcano in central Japan is the only active volcano among the Yatsugatake volcano group. It has effused nine lava flows, most of which have not been dated. For this study, we ascertained the eruption ages of the latest lava (Y9) and second most recent lava (Y8) using radiocarbon ( 14 C), thermoluminescence (TL), and paleomagnetic dating methods. Results revealed the eruption ages of the two lava flows and the recent eruption history of Yokodake volcano. Yokodake volcano effused its Y8 lava flow at ca. 3.4 ka, ejected NYk-2 tephra with explosive eruption at ca. 2.4–2.2 ka, and effused the Y9 lava flow associated with Y9-T tephra at ca. 0.6 ka. Magma eruption rates of Yokodake at 34 ky and 3.4 ky were estimated as about 9 × 10 −3 km 3 /ky and 1 × 10 −2 km 3 /ky, indicating a stable eruption rate maintained during the past 34 ky. This result suggests that Yokodake volcano retains some potential for eruption, although the volcanic activity of the Yatsugatake volcanoes (10 −1 –10 −2 km 3 /ky) has weakened over time.
    Effusive eruption
    Dense-rock equivalent
    Peléan eruption
    Lateral eruption
    Phreatic eruption
    Vulcanian eruption
    Volcanic hazards
    Lateral eruption
    Phreatic eruption
    Dense-rock equivalent
    Effusive eruption
    Peléan eruption
    Phreatomagmatic eruption
    Vulcanian eruption
    Volcanic hazards
    Citations (5)
    Lateral eruption
    Phreatic eruption
    Peléan eruption
    Effusive eruption
    Dense-rock equivalent
    Strombolian eruption
    Stratovolcano
    Vulcanian eruption
    Magma chamber
    Citations (91)
    By research with field investigation and observation records of volcanic eruption,combining with the achievement in volcanic research home and abroad,the authors discuss the volcanic eruption features of Laoheishan and Huoshaoshan in Wudalianchi of Heilongjiang,China in volcanic genetic type,eruption mode,eruption symptom and other aspects,and point out that the Laoheishan and Huoshaoshan volcanoes are monogenetic in genetic type,the eruption mode is not a simple way of central eruption,but experienced fission eruption turn to central eruption.Through the analysis of volcanic eruption observational record and the comparison with foreign volcanoes,it is revealed that this volcanic eruption possesses precursor which features benefit the monitor and forecast future volcanic eruption.
    Peléan eruption
    Dense-rock equivalent
    Vulcanian eruption
    Effusive eruption
    Lateral eruption
    Phreatic eruption
    Citations (1)