Geology topics

Research about Kīlauea Volcano

Source-linked reports with geographic coverage including Kīlauea Volcano.

At least 19 recordsLinked to original sources

USGS2024

Using ground crack and very low frequency measurements to map the location of the June 2007 Father’s Day dike, Kīlauea Volcano

An intrusion into Kīlauea’s upper East Rift Zone during June 17–19, 2007, during the 1983–2018 Pu‘u‘ō‘ō eruption, led to widespread ground cracking and a small (approximately 1,525 cubic meters) eruption on the northeast flank of Kānenuiohamo, a cone about 6 kilometers upslope from Pu‘u‘ō‘ō. Transmitted and induced very low frequency (VLF) magnetic fields were measured with a handheld VLF receiver along transects spanning the dike trace, and zones of ground cracking related to the intrusion were mapped. The locations of crack zones and the VLF receiver measurements suggest that the Father’s Day dike splayed as it approached the surface, dividing into four segments—one between Pauahi Crater and Pu‘uhuluhulu and three en echelon segments near Kānenuiohamo. The dike did not extend appreciably northeastward beyond the eruption site.

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USGS2024

Chemistry, growth, and fate of the unique, short-lived (2019–2020) water lake at the summit of Kīlauea Volcano, Hawaii

Less than a year after the 2018 Kīlauea caldera collapse and eruption, water appeared in newly deepened Halemaʻumaʻu crater. The lake—unprecedented in the written record—grew to a depth of ∼50 m before lava from the December 2020 eruption boiled it away. Surface water heightened concerns of potential phreatic or phreatomagmatic explosions but also offered a new means of possibly identifying eruption precursors. The U.S. Geological Survey Hawaiian Volcano Observatory (HVO) monitored the lake via direct visual observation, webcams, thermal imaging, colorimetry, and laser rangefinders. HVO also employed uncrewed aircraft systems to sample the water and measure near-lake gas composition. The lake's δD and δ 18 O indicate a groundwater source with substantial evaporation. The initial sample had a salinity (total dissolved solids concentration) of 71,000 mg/L and was rich in sulfate (∼53,000 mg/L), iron (∼500 mg/L), and magnesium (∼10,000 mg/L). Subsequent samples were slightly more dilute. The water's pH (∼4), δ 34 S (+4.3‰), and surface temperatures (up to 85°C) suggest, rather than significant scrubbing of magmatic volatiles, leaching of basalt and reactions with sulfate minerals resulted in high concentrations of sulfate and other solutes. Thermodynamic modeling and precipitate mineralogy indicate that water composition was controlled by iron oxidation and sulfate dissolution. Although the lake exhibited no detectable precursors before the next eruption, and phreatic or phreatomagmatic explosions did not materialize, our multi-parameter approach to monitoring yielded an enhanced understanding of the hydrologic, geologic, and magmatic conditions that led to the formation of the unique and short-lived lake.

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USGS2024

USGS and social media user dialogue and sentiment during the 2018 eruption of Kīlauea Volcano, Hawaii

Responsive and empathic communication by scientists is critical for building trust and engagement with communities, which, in turn, promotes receptiveness toward authoritative hazard information during times of crisis. The 2018 eruption of Hawai‘i's Kīlauea Volcano was the first volcanic crisis event in which communication via the U.S. Geological Survey (USGS) social media group, “USGS Volcanoes,” played a major role in providing eruption information to publics. Providing a concrete assessment of the social media effort during the eruption is necessary for optimizing future social media hazard crisis communication. We present qualitative and quantitative analyses of USGS Volcanoes' Facebook posts and over 22,000 follow-on comments spanning the 2018 eruption. Our analyses reveal that, for the 16 posts with the highest user engagement, USGS Volcanoes and informed non-USGS users directly answered 73% of questions and directly corrected or called out inaccuracies in over 54% of comments containing misinformation. User sentiments were 66% positive on average per comment thread regarding eruption information, and user feedback toward USGS Volcanoes, USGS scientists, or the Hawaiian Volcano Observatory was 86% positive on average. Quantitative sentiment analysis reveals a 61% correlation between users' overall expressed sentiments and frequency of the word “thank,” providing further evidence that social media engagement by USGS Volcanoes and informed users positively impacted collective user sentiment. Themes emerging from our qualitative thematic analysis illustrate how communication strategies employed by USGS Volcanoes successfully engaged and benefitted users, providing insights for communicating with publics on social media during crisis situations.

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USGS2024

Insights into magma storage depths and eruption controls at Kīlauea Volcano during explosive and effusive periods of the past 500 years based on melt and fluid inclusions

Kīlauea Volcano experiences centuries-long cycles of explosive and effusive eruptive behavior, but the relation, if any, between these eruptive styles and changing conditions in the magma plumbing system remains poorly known. We analyze olivine-hosted melt and fluid inclusions to determine magma storage depths during the explosive-era Keanakākoʻi Tephra eruptions (∼1500–1840 CE) and compare these results to modern effusive-era Kīlauea eruptions (1959 Kīlauea Iki, 1960 Kapoho, 2018 lower East Rift Zone). We find that shallow (1–3 km) magma storage has persisted for centuries at Kīlauea, spanning both explosive and effusive periods. In contrast, mid-crustal zones of magma storage shallowed over time, from 5 to 8 km during the Keanakākoʻi sequence to 3–5 km during the modern effusive period. Melt and fluid inclusions in high-forsterite olivine (Fo 86–89 ) trapped at shallow depths indicate that high-temperature magmas (1200 to ∼1300 °C) commonly reach depths of ≤3 km. CO 2 -rich fluid inclusions are present in olivine from all investigated Kīlauea eruptions but are larger and much more abundant in Keanakākoʻi units, which we interpret as indicating that a greater volume fraction of exsolved CO 2 -rich fluid was present in pre-eruptive Keanakākoʻi melts. Increased amounts of CO 2 -rich fluids in the Keanakākoʻi-era magmas would have increased magma buoyancy and driven rapid magma ascent, thereby increasing eruption energy and enhancing near-surface magma-water interactions compared to the current effusive period.

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USGS2023

Hawaiian volcanic ash, an airborne fomite for nontuberculous mycobacteria

Nontuberculous mycobacteria (NTM) are environmentally acquired opportunistic pathogens that can cause chronic lung disease. Within the U.S., Hawai'i shows the highest prevalence rates of NTM lung infections. Here, we investigated a potential role for active volcanism at the Kīlauea Volcano located on Hawai'i Island in promoting NTM growth and diversity. We recovered NTM that are known to cause lung disease from plumbing biofilms and soils collected from the Kīlauea environment. We also discovered viable Mycobacterium avium, Mycobacterium abscessus , and Mycobacterium intracellulare subsp. chimaera on volcanic ash collected during the 2018 Kīlauea eruption. Analysis of soil samples showed that NTM prevalence is positively associated with bulk content of phosphorus, sulfur, and total organic carbon. In growth assays, we showed that phosphorus utilization is essential for proliferation of Kīlauea-derived NTM, and demonstrate that NTM cultured with volcanic ash adhere to ash surfaces and remain viable. Ambient dust collected on O'ahu concurrent with the 2018 eruption contained abundant fresh volcanic glass, suggestive of inter-island ash transport. Phylogenomic analyses using whole genome sequencing revealed that Kīlauea-derived NTM are genetically similar to respiratory isolates identified on other Hawaiian Islands. Consequently, we posit that volcanic eruptions could redistribute environmental microorganisms over large scales. While additional studies are needed to confirm a direct role of ash in NTM dispersal, our results suggest that volcanic particulates harbor and can redistribute NTM and should therefore be studied as a fomite for these burgeoning, environmentally acquired respiratory infections.

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USGS2023

Complex styles of phreatomagmatic explosions at Kīlauea Volcano, Hawaii, controlled by magma structure

Explosive eruptions at basaltic volcanoes remain poorly understood. Kīlauea Volcano is a type locality for basaltic eruptions and is well-known for effusive activity. However, more than 7 m of phreatomagmatic Keanakākoʻi Tephra unit D deposits from explosive eruptions crown the southern rim of the summit caldera and provide a stark reminder of Kīlauea’s explosive past and future potential. We used detailed field observations as well as granulometric and morphological analysis of 100 samples from two proximal sections to assess the eruption style and fragmentation mechanism. The deposits can be divided into four subunits, six different lithofacies, and contain three juvenile tephra components. Each juvenile component shows distinct shape variability resulting from molten fuel-coolant interaction (MFCI) explosions of magma of variable vesicularity. Fragmentation of dense glass generates olive-green ash, fragmentation of low to moderately vesicular magma generates a dark gray ash-lapilli component, and fragmentation of highly vesicular magma generates light-yellow pumice. Our work shows that magma structure impacts MFCI explosion efficiency. Small-scale planar bedding throughout most of the deposit points to a general eruption style of small, frequent explosions generating low plumes. Thicker beds of accretionary lapilli of fine-extremely fine ash are related to very efficient magma-water mixing. Pyroclastic density current (PDC) deposits in the upper part of the stratigraphy contain at least three flows but show no significant dune or cross-bedding structures. We suggest that this is a function of the vent being situated in a caldera that was then ∼600 m deep, where the caldera wall acted as a barrier and changed the flow dynamics to very dilute overspills and co-PDC plume falls over the wall. Deconvolution modeling of the polymodal grain size distributions is used to assess grain size changes of each juvenile component for this deposit, which greatly improves interpretation of lithofacies generation and eruption dynamics. Size-correlated shape parameters show that shape data across a wide size range are needed to accurately track grain shapes. This study demonstrates how careful examination of grain size and shape of juvenile tephra clasts can help volcanologists understand how effusive basaltic volcanoes can become violently explosive.

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USGS2023

Years of magma intrusion primed Kīlauea Volcano (Hawai'i) for the 2018 eruption: Evidence from olivine diffusion chronometry and monitoring data

The mechanisms that led to the exceptionally large Kīlauea 2018 eruption are still poorly understood and actively debated. External processes such as rainfall events or flank sliding have been proposed to play a triggering role. Here, we present field, geophysical, and petrological observations to show that internal changes within the magmatic plumbing system most likely led to the eruption. Chemical zoning in olivine crystals records the intrusion of primitive magma that is concurrent with deep seismicity and inflation at the volcano’s summit. Magma replenishment and pressurization of the summit reservoirs already started around 2014 and accelerated towards the eruption. Kīlauea volcano was therefore primed to experience a shift in eruptive activity in 2018. This pressure increase associated with reservoir replenishment may have been sufficient to overcome a previously blocked conduit. These findings imply that precursory signs of years of protracted magma intrusion and pressurization of the system may be recognizable in the future, which could lead to improved hazards mitigation.

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USGS2023

The 2018 eruption of Kīlauea: Insights, puzzles, and opportunities for volcano science

The science of volcanology advances disproportionately during exceptionally large or well-observed eruptions. The 2018 eruption of Kīlauea Volcano (Hawai‘i) was its most impactful in centuries, involving an outpouring of more than one cubic kilometer of basalt, a magnitude 7 flank earthquake, and the volcano’s largest summit collapse since at least the nineteenth century. Eruptive activity was documented in detail, yielding new insights into large caldera-rift eruptions; the geometry of a shallow magma storage-transport system and its interaction with rift zone tectonics; mechanisms of basaltic tephra-producing explosions; caldera collapse mechanics; and the dynamics of fissure eruptions and high-volume lava flows. Insights are broadly applicable to a range of volcanic systems and should reduce risk from future eruptions. Multidisciplinary collaboration will be required to fully leverage the diversity of monitoring data to address many of the most important outstanding questions.

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USGS2022

Incremental caldera collapse at Kīlauea Volcano recorded in ground tilt and high-rate GNSS data, with implications for collapse dynamics and the magma system

Ground deformation during caldera collapse at Kīlauea Volcano in 2018 was recorded in unprecedented detail on a network of real-time GNSS (Global Navigation Satellite System) and tilt instruments. Observations informed hazard assessments during the eruption and now yield insight into collapse dynamics and the magma system. The caldera grew in size over 78 days in a series of repeating, quasi-periodic ∼ "> ∼ ∼ day-long cycles. During abrupt seconds-long collapse events, fault-bounded caldera blocks subsided by meters, while the surrounding edifice moved upwards and outwards by as much as tens of centimeters. Between collapses, stations outside of the caldera moved inwards and downwards at decreasing rates, largely reversing co-collapse deformations. In total, the caldera subsided >500 m at its deepest point while the surrounding edifice subsided mostly less than 2 m chiefly in a region south of the new caldera. Ground deformation reflects magma withdrawal from the broader summit magma system and faulting processes related to collapse. Deformation cycles were caused by step-like pressurization of Kīlauea’s subcaldera magma system due to episodic, stick-slip roof rock subsidence, followed by gradual pressure reduction as magma continued to drain from the summit, stressing faults and leading to subsequent collapses. A model of piston-like subsidence implies that larger collapses increased pressure in a compressible subcaldera magma reservoir by several MPa, driving flow to the rift through a relatively wide conduit. Collapses did not fully recover precollapse pressure loss in the reservoir, and excess pressure driving the eruption was very low; the eruption was thus tenuously sustained by collapses. Important open questions remain about the relation between caldera floor subsidence and ground deformation, the role of other magma storage zones, and the interplay of summit and rift processes in controlling the evolution of the eruption.

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USGS2022

Magnetotelluric investigations of the Kīlauea Volcano, Hawaii

In 2002 and 2003 a collaborative effort was undertaken between Lawrence Berkeley National Laboratory, Sandia National Laboratories, the U.S. Geological Survey (USGS) Menlo Park, the USGS Hawaiian Volcano Observatory, and Electromagnetic Instruments Inc. to study the Kīlauea volcano in Hawaii using the magnetotelluric (MT) technique. The work was motivated by a desire to improve understanding of the magma reservoirs and conduits within Kīlauea and the East and Southwest Rift zones, which has implications for understanding Kīlauea's plumbing system. An improved understanding of the rift zones has implications in understanding large-scale landslides that are generated in the Hilina Slump, which produce significant impacts on coastal communities. Up to eight stations operated simultaneously, with multiple remote reference sites, and data were processed using multi-station robust processing techniques. In total, data were acquired at 70 sites over the Southwest and East rift zones. Good to excellent quality data were obtained even in the harshest conditions, such as those encountered on the fresh lava flows of the East Rift Zone, where electrical contact resistances are on the order of 100 kΩ. A three-dimensional (3D) MT model study was done to guide interpretation of the observed MT measurements. Synthetic modeling demonstrates that conductive bodies in the upper 3 km can be spatially resolved where MT station sampling is good. Resistivity anomalies in the 3D inversions have a high degree of spatial correlation with previously published seismic velocity anomalies beneath Kīlauea. Melt fractions between 0.096 and 0.117 are calculated for the Kīlauea and Puʻuʻōʻō low resistivity anomalies, respectively.

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USGS2022

Olivine and glass chemistry record cycles of plumbing system recovery after summit collapse events at Kīlauea Volcano, Hawai‘i

The eruptive activity of Kīlauea Volcano (Hawai‘i) in the past 2500 years has alternated between centuries-long periods dominated either by explosive or effusive eruptions. The onset of explosive periods appears to be marked by caldera collapse events at the volcano's summit accompanied by draining of Kīlauea's magmatic plumbing system. Here we leverage >1800 olivine forsterite (Fo) contents, >900 glass MgO contents, and estimated magma supply rates from the past six centuries to describe the relationships between summit collapse and the composition of erupted material. On a first order basis, the major element chemistry of the centuries-long eruptive periods largely originates from fundamental differences between fractional crystallization of shallowly stored magmas during high-supply effusive-dominated periods versus little evolution of mafic recharge magmas during low-supply explosive-dominated periods. The modern effusive period (1820s-present) is dominated by relatively evolved olivine forsterite contents (Fo81–82) for Kīlauea, which is interpreted to reflect a buffered crustal reservoir system in which shallow storage and fractional crystallization control the composition of magmas. In contrast, olivine crystals from the explosive Keanakāko‘i Tephra (1500 - early 1800s C.E.) are dominated by higher olivine forsterite contents (Fo89) which are interpreted to reflect more primitive compositions, are correlated with glass MgO compositions extending to high values (e.g.,11.0 wt%), and show signs of magma mixing (zoned olivine, bimodal Fo populations). These signatures reflect a disrupted reservoir system in which high-MgO recharge melts mix with melts left over from draining of the shallow (<5 km) magma plumbing. Superimposed on these explosive-effusive periods are three decades- to centuries long periods of progressively evolving olivine and glass compositions. Eruptions that occur after caldera collapse in ~1500C.E. and smaller scale crater collapse events in 1790 (inferred) and 1924 have heterogeneous olivine populations dominated by ≥Fo88 and typically high MgO glasses. These compositions reflect inefficient mixing of stored and primitive recharge magmas after the disruption of the shallow plumbing system. After these collapses, olivine Fo and glass MgO subsequently evolve to <Fo82 and <7.0 wt% compositions, reflecting the recovery of the crustal plumbing system to an end-member system state characterized by efficient mixing of recharge and stored magmas that serve to buffer the shallow magma reservoirs. These evolved signatures suggest that a mature and buffered reservoir system may be a key condition for significant disruptions of volcanic plumbing systems. Plumbing system recovery is slower following large-scale caldera collapse (hundreds of years) compared to recovery following smaller crater collapse (tens of years), which may be modulated by differences in magma supply rates. Following the 2018 crater collapse olivine populations have high-Fo but glasses are low MgO, suggesting that this collapse might have disrupted shallow magma pathways but not strongly impacted the reservoir(s). Ultimately, olivine and glass major element chemistry record the impacts of caldera and smaller but significant summit crater collapse events at Kīlauea and could be used to provide a framework for better characterizing long-term volcano evolution in Hawai‘i and shield volcanoes elsewhere.

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USGS2022

Development, structure, and behavior of a perched lava channel at Kīlauea Volcano, Hawaiʻi, during 2007

Channelized lava flows are commonly produced during the early stages of basaltic eruptions. These channels usually maintain their morphology until the eruption ends or discharge is diverted. In some instances, narrower channels can roof over, developing into lava tubes. We report here on a channelized flow erupted at Kīlauea volcano in 2007 that evolved into a “perched lava channel” composed of a string of interconnected, elongate lava pools, forming a lava channel/lava pool hybrid. The lava channel, which had a time-averaged discharge rate of ~3–9 m 3 /s, initially fed a series of flow branches that exhibited cooling-limited and volume-limited controls on flow length, sometimes with each process controlling a different morphological aspect of a single flow branch. The perched lava channel grew vertically primarily by overplating of the channel levees from frequent overflows, forming a compound flow field. This vertical growth only occurred when the distal end of the channel was blocked. When levee failure at the distal end of the channel caused the lava level in the channel to drop below the levee rim, no vertical growth occurred. Seeps of spiny lava and slabby pāhoehoe were common, erupting from uplift scarps on the channel levees, apparently fed by sills from denser, relatively crystal-rich material filling the bottom of the channel. We infer that lava in the channel was stratified in vesicularity and velocity, with foamy, vesicular, faster-moving lava at the top of the lava stream and denser, relatively outgassed, slower-moving lava filling the bottom of the channel. The channel levees were unstable, failing on several occasions, perhaps triggered by the levee seeps. The appearance of seeps, therefore, is one way of assessing the collapse potential of similar perched lava structures.

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USGS2022

Evolving magma temperature and volatile contents over the 2008–2018 summit eruption of Kīlauea Volcano

Magma rheology and volatile contents exert primary and highly nonlinear controls on volcanic activity. Subtle changes in these magma properties can modulate eruption style and hazards, making in situ inference of their temporal evolution vital for volcano monitoring. Here, we study thousands of impulsive magma oscillations within the shallow conduit and lava lake of Kīlauea Volcano, Hawai‘i, USA, over the 2008–2018 summit eruptive sequence, encoded by “very-long-period” seismic events and ground deformation. Inversion of these data with a petrologically informed model of magma dynamics reveals significant variation in temperature and highly disequilibrium volatile contents over days to years, within a transport network that evolved over the eruption. Our results suggest a framework for inferring subsurface magma dynamics associated with prolonged eruptions in near real time that synthesizes petrologic and geophysical volcano monitoring approaches.

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USGS2021

Crater growth and lava-lake dynamics revealed through multitemporal terrestrial lidar scanning at Kīlauea Volcano, Hawaiʻi

Lava lake surfaces display the tops of active magma columns and respond to eruption variables such as magmatic pressure, convection, degassing, and cooling, as well as interactions with the craters that contain them. However, they are challenging to study owing to the numerous hazards that accompany these eruptions, and they are typically difficult to observe because the emitted gas plumes obscure the lava lake surfaces. The 2008–2018 Overlook crater and lava lake at Kīlauea Volcano, Hawaiʻi, provided a remarkable opportunity to study several high-resolution data streams of eruption variables that impacted the lava lake. To investigate how the crater and associated lava lake responded to changes in these eruption variables, we acquired terrestrial light detection and ranging (lidar) surveys of the Overlook crater and lava lake surface from February 2012 through December 2013, supplemented with several earlier terrestrial and airborne lidar datasets, to quantitatively track changes in the shape of the lava lake surface and the crater walls. Lidar captures high-resolution data even when the lake is completely obscured by thick gas plumes. We used a novel “unrolling technique” to map volumetric changes in crater shape, because standard elevation differencing fails to capture all topographic changes on the nearly vertical, and sometimes overhanging, crater walls. We measured crater perimeter growth rates of approximately 52 meters per year from 2009 to 2013, with the greatest growth occurring along a line linking areas of persistent upwelling and downwelling. We suggest that the development of an oblong crater with a perimeter that grows linearly is best explained by a model where degradation is favored at the sites of persistent upwelling and downwelling and where growth is controlled by a lithology that varies little with respect to rock strength. We also found that most of the Overlook crater growth occurred during a relatively small number of significant rockfall events (~16) over this period. Additional lidar datasets revealed that the lava lake surface has a measurable slope from the areas of persistent upwelling to downwelling, although rockfalls from the crater walls temporarily changed the direction of crustal plate movement along with the magnitude and direction of the lava lake surface slope. Our study demonstrates that lidar is an effective tool for tracking the topography of an active volcanic crater when heavy outgassing renders other tools, such as structure from motion, ineffective.

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USGS2021

Evaluating lava flow propagation models with a case study from the 2018 eruption of Kīlauea Volcano, Hawai'i

The 2018 lower East Rift Zone (LERZ) eruption of Kīlauea, Hawai’i, provides an excellent natural laboratory with which to test models of lava flow propagation. During early stages of eruption crises, the most useful lava flow propagation equations utilize readily determined parameters and require fewer a priori assumptions about future behavior of the flow. Here, we leverage the numerous observations of lava flows collected over the duration of the eruption crisis at Kīlauea in 2018 to test simple lava flow propagation models. These models track the one-dimensional propagation of the flows according to three main rheological restraining forces: bulk viscosity, yield strength, and growth of a surface crust. We calculate the predicted changes in length through time of three flows that vary in bulk composition, crystal content, and total flow length. Cooler flows that are more crystal-rich tend to be more dominated by crust growth, though early stages of propagation can be controlled by bulk viscosity. We find that variations in effusion rate significantly impact flows that are short-lived; flows that are produced during steady-state effusion are readily approximated by average values for the entire flow. Thus, accurate knowledge of variations in effusion rate are critical to accurate lava flow propagation forecasting.

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USGS2021

Post audit of simulated groundwater flow to a short-lived (2019-2020) crater lake at Kīlauea Volcano

About 14.5 months after the 2018 eruption and summit collapse of Kīlauea Volcano, Hawaiʻi, liquid water started accumulating in the deepened summit crater, forming a lake that attained 51 m depth before rapidly boiling off on December 20, 2020, when an eruption from the crater wall poured lava into the lake. Modeling the growth of the crater lake at Kīlauea summit is important for assessing the potential for explosive volcanism. Our current understanding of the past 2500 years of eruptive activity at Kīlauea suggests a slight dominance of explosive behavior over effusive. The deepened summit crater and presence of the crater lake in 2019 raised renewed concerns about explosive activity. Groundwater models using hydraulic-property data from a nearby drillhole successfully forecast the timing and rate of lake filling. Here we compare the groundwater-model predictions with observational data through the demise of the crater lake, examine the implications for local water-table configuration, consider the potential role of evaporation and recharge (neglected in previous models), and briefly discuss the energetics of the rapid boil-off. This post audit of groundwater-flow models of Kīlauea summit shows that simple models can sometimes be used effectively to simulate complex settings such as volcanoes.

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USGS2021

Sources of volcanic tremor associated with the summit caldera collapse during the 2018 east rift eruption of Kīlauea Volcano, Hawai'i

Volcanic tremor occurring at the beginning of the 2018 Kīlauea eruption is characterized using both seismic and tilt data recorded at the Kīlauea summit. An automatic seismic network-based approach detects several types of tremor including (a) 0.5–1 Hz long-period tremor preceding the eruption, located at the south-southwest edge of Halema'uma'u Crater and attributed to the quasi-steady radiation from a shallow hydrothermal system and (b) two sequences of gliding tremor at the beginning of the eruption, both with locations on the edges of the crater and within it. The first sequence is attributed to two swarms of low-amplitude regularly repeating earthquakes induced by the jerky motions of a cylindrical rock piston with radius of 325 m, height of 250 m, and mass of 2.07 × 10 11 kg, progressively intruding 12.3 m into the shallow hydrothermal system with volume of 10 8 m 3 and depth extent of 300 m. The second sequence is attributed to a gradual evolution in the properties of a bubbly magma within an east-striking dike below Halema'uma'u Crater, impacted by repeated roof collapses. A fluid-filled crack model points to a decrease in gas volume fraction from 4.22% to 1.6 × 10 −2 % in the magma filling the dike, and a model of gas retro-diffusion within the melt suggests a two orders of magnitude decrease in bubble number density from 7 × 10 8 m −3 down to 4 × 10 6 m −3 . Both models feature a quasi to totally degassed magma by May 26.

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USGS2021

Volatile metal emissions from volcanic degassing and lava–seawater interactions at Kīlauea Volcano, Hawai’i

Volcanoes represent one of the largest natural sources of metals to the Earth’s surface. Emissions of these metals can have important impacts on the biosphere as pollutants or nutrients. Here we use ground- and drone-based direct measurements to compare the gas and particulate chemistry of the magmatic and lava–seawater interaction (laze) plumes from the 2018 eruption of Kīlauea, Hawai’i. We find that the magmatic plume contains abundant volatile metals and metalloids whereas the laze plume is further enriched in copper and seawater components, like chlorine, with volatile metals also elevated above seawater concentrations. Speciation modelling of magmatic gas mixtures highlights the importance of the S 2− ligand in highly volatile metal/metalloid degassing at the magmatic vent. In contrast, volatile metal enrichments in the laze plume can be explained by affinity for chloride complexation during late-stage degassing of distal lavas, which is potentially facilitated by the HCl gas formed as seawater boils.

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