Submarine radial vents on Mauna Loa Volcano, Hawai'i

A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created ''irregular'' cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km 2 of seafloor and comprise a total volume of ∼2 × 10 9 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level

Dynamics of magma mixing and magma mobilisation beneath Mauna Loa—insights from the 1950 AD Southwest Rift Zone eruption

Eruptions from Mauna Loa’s Southwest Rift Zone (SWRZ) pose a significant threat to nearby communities due to high eruption rates and steep slopes resulting in little time for evacuation. Despite the large body of research done on Mauna Loa, knowledge of the timing and duration of magma residence and transfer through its internal plumbing system is still poorly constrained. This study presents a first quantitative look at thermochemical conditions and timescales of potentially deep storage and disaggregation of magmatic mush during the run-up to the voluminous 1950 AD SWRZ eruption. Details of heterogeneous compositions and textures of the macrocryst and glomerocryst cargo in 1950 AD lavas suggest magma mixing and crystal recycling along the entire plumbing system. Furthermore, the crystal cargo contains evidence for the direct interaction between primitive, deeply stored magma and pockets of more evolved magma stored at shallow to intermediate depths. An enigmatic attribute of 1950 near-vent lava is the near-ubiquitous presence of subhedral, unreacted Mg-rich orthopyroxene phenocrysts (Mg#>80). Phase relations of Mauna Loa olivine-tholeiite indicate that orthopyroxene joins olivine as a primary phase at pressures higher than 0.6 GPa. Coexisting Mg-rich olivine and orthopyroxene and the occurrence of harzburgitic (olivine-orthopyroxene) glomerocrysts provide evidence for cognate crystallisation at near-Moho (~ 18 km) depths (Thornber and Trusdell 2008). Petrogenetically diverse populations of glomerocrysts and macrocrysts alongside evidence of multilevel magma storage indicate a network of ephemeral and possibly interconnected magma pockets from near-Moho depths to the upper/mid-crust. Fe-Mg diffusion chronometry applied to 1950 AD olivine populations implies rapid mobilisation and transport of large volumes of magma (376×10⁶ m³) from near-Moho storage to the surface within less than 8 months, with little residence time (~ 2 weeks) in the shallow (3–5 km) plumbing system

Explosive Activity on Kīlauea's Lower East Rift Zone Fueled by a Volatile-Rich, Dacitic Melt

Abstract: Magmas with matrix glass compositions ranging from basalt to dacite erupted from a series of 24 fissures in the first 2 weeks of the 2018 Lower East Rift Zone (LERZ) eruption of Kīlauea Volcano. Eruption styles ranged from low spattering and fountaining to strombolian activity. Major element trajectories in matrix glasses and melt inclusions hosted by olivine, pyroxene and plagioclase are consistent with variable amounts of fractional crystallization, with incompatible elements (e.g., Cl, F, and H2O) becoming enriched by 4–5 times as melt MgO contents evolve from 6 to 0.5 wt%. The high viscosity and high H2O contents (∼2 wt%) of the dacitic melts erupting at Fissure 17 account for the explosive Strombolian behavior exhibited by this fissure, in contrast to the low fountaining and spattering observed at fissures erupting basaltic to basaltic‐andesite melts. Saturation pressures calculated from melt inclusion CO2‐H2O contents indicate that the magma reservoir(s) supplying these fissures was located at ∼2–3 km depth, which is in agreement with the depth of a dacitic magma body intercepted during drilling in 2005 (∼2.5 km) and a seismically imaged low Vp/Vs anomaly (∼2 km depth). Nb/Y ratios in erupted products are similar to lavas erupted between 1955 and 1960, indicating that melts were stored and underwent variable amounts of crystallization in the LERZ for >60 years before being remobilized by a dike intrusion in 2018. We demonstrate that extensive fractional crystallization generates viscous and volatile‐rich magma with potential for hazardous explosive eruptions, which may be lurking undetected at many ocean island volcanoes

Reconstructing Magma Storage Depths for the 2018 Kı̄lauean Eruption From Melt Inclusion CO ₂ Contents: The Importance of Vapor Bubbles

The 2018 lower East Rift Zone (LERZ) eruption and the accompanying collapse of the summit caldera marked the most destructive episode of activity at Kı̄lauea Volcano in the last 200 years. The eruption was extremely well-monitored, with extensive real-time lava sampling as well as continuous geodetic data capturing the caldera collapse. This multiparameter data set provides an exceptional opportunity to determine the reservoir geometry and magma transport paths supplying Kı̄lauea’s LERZ. The forsterite contents of olivine crystals, together with the degree of major element disequilibrium with carrier melts, indicates that two distinct crystal populations were erupted from Fissure 8 (termed high- and low-Fo). Melt inclusion entrapment pressures reveal that low-Fo olivines (close to equilibrium with their carrier melts) crystallized within the Halema’uma’u reservoir (∼2-km depth), while many high-Fo olivines (>Fo81.5; far from equilibrium with their carrier melts) crystallized within the South Caldera reservoir (∼3–5-km depth). Melt inclusions in high-Fo olivines experienced extensive post-entrapment crystallization following their incorporation into cooler, more evolved melts. This favored the growth of a CO2-rich vapor bubble, containing up to 99% of the total melt inclusion CO2 budget (median = 93%). If this CO2-rich bubble is not accounted for, entrapment depths are significantly underestimated. Conversely, reconstructions using equation of state methods rather than direct measurements of vapor bubbles overestimate entrapment depths. Overall, we show that direct measurements of melts and vapor bubbles by secondary-ion mass spectrometry and Raman spectroscopy, combined with a suitable H2O-CO2 solubility model, is a powerful tool to identify the magma storage reservoirs supplying volcanic eruptions. Key Points Petrological, gaseous and geophysical observations can be reconciled by a model where Fissure 8 was supplied from two summit storage reservoirs (∼1–2- and 3–5-km depth) Extensive post-entrapment crystallization of melt inclusions within high-Fo olivines (Fo > 81.5) caused ∼90% of the CO2 to enter the vapor bubble Raman analyses of vapor bubbles combined with choice of a suitable H2O-CO2 solubility model is required to accurately determine magma storage depths Plain Language Summary Pockets of frozen magma trapped within olivine crystals, termed “melt inclusions,” can provide information about the depths at which magma is stored beneath the surface prior to a volcanic eruption. This is because the amount of CO2 and H2O that can be dissolved in a melt is dependent on the pressure, and therefore the depth. We examine melt inclusions from lava flows produced during the 2018 eruption of Kı̄lauea Volcano. Previous work, based on geophysics, has shown that magma is stored in two main reservoirs at Kı̄lauea, located at ∼1–2- and ∼3–5-km depth. However, because many melt inclusions host almost all of their CO2 within a vapor bubble, which is rarely measured, previous petrological estimates of magma storage depths at Kı̄lauea do not align with the depths of the two reservoirs identified by geophysics. In this study, we measure the amount of CO2 in the glass and the bubble using secondary-ion mass spectrometry and Raman spectroscopy, respectively. By adding these two measurements together, we can reconstruct the amount of CO2 that was present when melt inclusions were trapped. Calculated depths align remarkably well with geophysical estimates, and demonstrate that the 2018 eruption was supplied by both magma storage reservoirs

Non-Equilibrium Evolution Thermodynamics Theory

Alternative approach for description of the non-equilibrium phenomena arising in solids at a severe external loading is analyzed. The approach is based on the new form of kinetic equations in terms of the internal and modified free energy. It is illustrated by a model example of a solid with vacancies, for which there is a complete statistical ground. The approach is applied to the description of important practical problem - the formation of fine-grained structure of metals during their treatment by methods of severe plastic deformation. In the framework of two-level two-mode effective internal energy potential model the strengthening curves unified for the whole of deformation range and containing the Hall-Petch and linear strengthening sections are calculated.Comment: 7 pages, 1 figur

Population Density Estimates and Growth Rates of Eleutherodactylus coqui in Hawaii

The Puerto Rican terrestrial frog (Eleutherodactylus coqui) has received considerable attention in Hawaii because of its rapid spread, loud mating calls, and its potential threat to native species. Thus far, its invasion potential on the Island of Hawaii remains poorly understood. Critical components for determining this potential are robust estimates of abundance and vital rates across habitat types. To address this lack of information, we used mark-recapture methods to estimate E. coqui survival and abundance, determine growth rates of adult male and female frogs, and relate densities to elevation, snout–vent length (SVL), habitat structure, and invertebrate abundance. Mean adult E. coqui density across eight sites was 62 ± 12 adults/100 m2 and ranged from 6-138 adults/100 m2. Our three-year mean adult density estimates were three times greater at three of our study sites (100 adults/100 m2) than the highest long-term estimates from Puerto Rico (33 adults/100 m2). Mean individual growth rates were 0.0078 mm/day (± 0.007 SD, N = 87) for males and 0.0097 mm/day (± 0.009 SD, N = 11) for females. Frogs of similar size were found to be growing slower in Hawaii than Puerto Rico. We found no relationship between elevation and E. coqui density or elevation and SVL or between invertebrate abundance and E. coqui density. However, there was a positive relationship between understory structure and E. coqui density. This relationship suggests that removing understory structure could reduce E. coqui densities, although other potential implications of this management treatment should be considered

New York Mayor's Court. William Trusdell against Francis Harison, Esq. For arresting, imprisoning and keeping the Plaintif Ten weeks in prison, at the suit of Joseph Weldon, without authority ... [Dated New York, August 25th, 1733].

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