Linking Magma Storage and Ascent to Eruption Volume and Composition at an Arc Caldera

Miller, David; Bennington, N. L.; Haney, Matthew M.; Bedrosian, Paul A.; Key, Kerry; Thurber, C. H.; Hart, L.; Ohlendorf, S. J.

doi:10.1029/2020gl088122

Cited by 10 publications

(5 citation statements)

References 57 publications

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“…The source depth accounting for the inflation immediately after the 2008 eruption in our study is very close to that before 2008, which is consistent with the progressive deepening in the deflation source during the 2008 eruption in previous inter‐eruption observations by Lu and Dzurisin (2010) and Freymueller and Kaufman (2010), indicating magma accumulation inside the shallow reservoir resumed rapidly after the eruption. The inferred locations of the magma reservoir from InSAR coincides with the low seismic velocity zone inferred from seismic radial anisotropy and resistivity survey (Miller et al., 2020).…”

Section: Discussionsupporting

confidence: 78%

Inflation of Okmok Volcano During 2008–2020 From PS Analyses and Source Inversion With Finite Element Models

2021

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Okmok, located in the northeast of the Umnak Island, Alaska, is one of the most activate volcanoes in the Aleutian Island Arc. Two major catastrophic pyroclastic eruptions with max Volcanic Explosivity Index exceeded 4, that is, Okmok Caldera Forming Eruption (CFE) I and Okmok CFE II dated about 12,000 years and 2050 14 C years ago, respectively, shaped the major topographic morphology of Okmok (Byers, 1959;Larsen et al., 2007). In addition to the current caldera rim, evidence from six arctic ice cores shows the Okmok CFE II may also be responsible for one of the coldest decades of recent millennia in the Northern Hemisphere (McConnell et al., 2020). Since 1900, multiple effusive eruptions have been documented at Okmok producing a new prominent cone, Cone A. From 1943 to 1997, all of Okmok's eruptions have originated from Cone A (Figure 1; Lu & Dzurisin, 2014). The most recent eruption in 2008, spanned from July 12 to mid-August, was the most explosive eruption since at least the late nineteenth century, and produced a minimum of 0.17 3 km E of dense rock-equivalent ejecta (Larsen et al., 2015). As opposed to previous eruptions, the 2008 eruption emanated from the northwest flank of an existing cinder cone (Cone D), about 5 km E

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Section: Discussionsupporting

confidence: 78%

Inflation of Okmok Volcano During 2008–2020 From PS Analyses and Source Inversion With Finite Element Models

2021

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“…The negative anisotropy beneath MSH terminates before reaching Mount Hood in the south. Negative radial anisotropy has also been previously detected in several other volcanic systems, including Piton de la Fournaise, Colima, and Okmok, and is interpreted to represent concentrations of dikes responsible for rapid magma transport (D. Miller et al, 2020;Mordret et al, 2015;Spica et al, 2017). A similar structure here could suggest a more prevalent magma transport through dikes beneath MSH (Figure 10g) compared to the other three volcanoes of Mt.…”

Section: Sub-arc Anisotropy and Implications For Magmatic Pathwayssupporting

confidence: 78%

“…In the crust, radial anisotropy is often taken as a strong indicator of tectonic deformation as its origin usually involves strain‐induced alignments of fractures in the shallow crust and anisotropic crustal minerals and foliations in the mid‐lower crust (Almqvist & Mainprice, 2017; Crampin, 1981, 1984; Mainprice & Nicolas, 1989). In volcanic settings, radial anisotropy can provide new insights into potential structural fabrics related to magma organization such as sill or dike complexes (Chambers et al., 2021; Harmon & Rychert, 2015; Jaxybulatov et al., 2014; Jiang et al., 2018; Lynner et al., 2018; D. Miller et al., 2020).…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, this study uses radially anisotropic surface wave tomography to constrain differences in vertically polarized shear velocity ( V SV ) and horizontally polarized shear velocity ( V SH ). Recent studies have shown distinctive radial anisotropic structure, with co‐located low V S and V SH > V SV , underlying volcanic systems in arc and intraplate settings with compositionally evolved magmas (Harmon & Rychert, 2015; Jaxybulatov et al., 2014; Jiang et al., 2018; Lynner et al., 2018; D. Miller et al., 2020). These results are consistent with the organization of melt into horizontally elongated sill‐like volumes.…”

Section: Introductionmentioning

confidence: 99%

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Segmentation and Radial Anisotropy of the Deep Crustal Magmatic System Beneath the Cascades Arc

Jiang

Schmandt

Abers

et al. 2023

Geochem Geophys Geosyst

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Subduction zone plate boundaries extend for hundreds to thousands of kilometers along strike fueling volcanic arcs on the overriding plate. Slab inputs to the mantle that are continuous along strike give rise to discrete volcanoes with variable distance from the plate boundary and along-strike spacing (e.g., Lee & Wada, 2017;O'Hara et al., 2020) as well as compositional heterogeneity within and between different volcanoes (e.g., Wanke et al., 2019). Heterogeneity also occurs at intermediate scales in which groups of adjacent volcanoes with common geochemical or eruptive characteristics define along-strike segments (O'Hara et al., 2020;Schmidt et al., 2008). It is unclear how these aspects of volcanic arc heterogeneity are linked to deep crustal magma reservoirs, which process mantle melt inputs into their eventual volcanic or intrusive products. Magma reservoirs beneath volcanic arcs are thought to span the entire crustal depth range and create long-lived hot zones, although the specific organization of melt accumulations is transient (Cashman Abstract Volcanic arcs consist of many distinct vents that are ultimately fueled by the common melting processes in the subduction zone mantle wedge. Seismic imaging of crustal-scale magmatic systems can provide insight into how melt is organized in the deep crust and eventually focused beneath distinct vents as it ascends and evolves. Here, we investigate the crustal-scale structure beneath a section of the Cascades arc spanning four major stratovolcanoes: Mt. Hood, Mt. St. Helens (MSH), Mt. Adams (MA), and Mt. Rainier, based on ambient noise data from 234 seismographs. Simultaneous inversion of Rayleigh and Love wave dispersion constrains the isotropic shear velocity (Vs) and identifies radially anisotropic structures. Isotropic Vs shows two sub-parallel low-Vs zones (∼3.45-3.55 km/s) at ∼15-30 km depth with one connecting Mt. Rainier to MA, and another connecting MSH to Mt. Hood, which are interpreted as deep crustal magma reservoirs containing up to ∼2.5%-6% melt, assuming near-equilibrium melt geometry. Negative radial anisotropy, from vertical fractures like dikes, is prevalent in this part of the Cascadia, but is interrupted by positive radial anisotropy, from subhorizontal features like sills, extending vertically beneath MA and Mt. Rainier at ∼10-30 km depth and weaker and west-dipping positive anisotropy beneath MSH. The positive anisotropy regions are adjacent to rather than co-located with the isotropic low-Vs anomalies. Ascending melt that stalled and mostly crystallized in sills with possible compositional differences from the country rock may explain the near-average Vs and positive radial anisotropy adjacent to the active deep crustal magma reservoirs.Plain Language Summary Volcanic arcs, a common result of subduction processes, comprise a large proportion of active volcanoes in the world and pose significant hazards. Seismic tomography measures variations of seismic wave speed in the subsurface, which can then be used to infer important properties of the vo...

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“…Seismic tomography (broadly defined) continues to be a fundamental tool for understanding volcanic structure (e.g., Iyer and Dawson (1993); Lees 2007;Koulakov and Shapiro 2021). Ambient noise tomography studies, often in conjunction with other methods, have imaged the S-wave structure under volcanoes (Lin et al 2014;Kiser et al 2016;Ulberg et al 2020), where S-wave travel times are sparse in the seismic catalog (Nagaoka et al 2012;Jaxybulatov et al 2014;Flinders and Shen 2017;Heath et al 2018;Green et al 2020;Miller et al 2020). Towards the end of the 2010-2019 decade Janiszewski et al (2020) and Portner et al (2020) have illuminated the mid and lower crust of volcanoes using receiver functions within sparse networks.…”

Section: Illuminating the Magmatic Plumbing Systemmentioning

confidence: 99%

Trends in volcano seismology: 2010 to 2020 and beyond

2022

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Volcano seismology has been fundamental to our current understanding of crustal magma migration and eruption. The increasing availability of portable seismic networks with the creative use of seismic sources and ambient noise has led to a better understanding of the volcanic structure of many volcanoes and is producing increasingly detailed images of the volcanic subsurface. The past decade (2010-2020) has seen advances in our understanding of seismic sources under and surrounding volcanoes through precise locations, and through analysis of source mechanisms from seismic signals that are more varied and smaller in magnitude, reaching beyond traditional techniques. In tandem with continued research on fundamental physics-based understanding of volcano-seismic sources, new advances in computational analyses including machine learning methods will push our understanding of volcanic processes into the future. Incorporation of multidisciplinary geophysical observations (especially infrasound) has become commonplace, and our understanding of infrasound propagation and sources will feed back into our ability to monitor ongoing eruptions and surficial mass movements. Open-source codes will permit widespread evaluation and adoption of new methodologies for volcano-seismic analysis and inversion. Combined with quantitative and conceptual source models using improved structural constraints, these new methodologies will better characterize the range of volcano-seismic signal evolution scenarios and hold promise for creating better short-term forecasts. Finally, permanent instrumentation is available on an expanding range of volcanoes, and open data policies are increasingly making these data available to the scientific community in near real time.

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Linking Magma Storage and Ascent to Eruption Volume and Composition at an Arc Caldera

Cited by 10 publications

References 57 publications

Inflation of Okmok Volcano During 2008–2020 From PS Analyses and Source Inversion With Finite Element Models

Inflation of Okmok Volcano During 2008–2020 From PS Analyses and Source Inversion With Finite Element Models

Segmentation and Radial Anisotropy of the Deep Crustal Magmatic System Beneath the Cascades Arc

Trends in volcano seismology: 2010 to 2020 and beyond

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