Alison Hollomon Graettinger

University of Missouri–Kansas City | UMKC · Department of Geosciences

Call for abstract submission | IAVCEI 2025 Session title: "Small-scale volcanoes and their large-scale volcanic context" Deadline: 20 December 2024

Using a multidisciplinary approach to understand the subsurface processes behind the formation of maar‐diatreme volcanoes is of growing interest. While geophysical characterization can visualize the diatreme and the feeding dike system beneath the volcano at a reasonable scale, such data are rare and generally unavailable. Stratigraphic‐controlled...

We examine the morphology and chemistry of the Vikrahraun basaltic eruption emplaced at Askja Volcano, Iceland, from Oct. 26–Dec. 17, 1961. The eruption had three eruptive events, initiating with aʻa and followed by alternating aʻa and pahoehoe lava flow emplacement. We determine that while the eruption is chemically homogenous (Fe/Mg = 1.9–2.2, 47...

Accurate classification of terrestrial and non-terrestrial volcanic landforms requires a robust suite of morphometric parameters. The Small-volume Monogenetic Igneous Landforms and Edifices Statistics (SMILES) catalog contains the morphometric characterizations of mafic small-volume volcanic landforms and was created using uncrewed aerial system ph...

Blasting experiments were performed that investigate multiple explosions that occur in quick succession in unconsolidated ground and their effects on host material and atmosphere. Such processes are known to occur during phreatomagmatic eruptions at various depths, lateral locations, and energies. The experiments follow a multi‐instrument approach...

For decades scaled analog experiments have improved the understanding of a broad range of multiphase volcanological processes in controlled laboratory environments. Successfully modeled processes include magma flow through magma reservoirs, conduits and sheets, associated crustal deformation, lava flow, volcanic plume dynamics, ash cloud dispersion...

For decades, scaled analog experiments have improved the understanding of a broad range of multiphase volcanological processes in controlled laboratory environments. Successfully modeled processes include magma flow through magma reservoirs, conduits and sheets, associated crustal deformation, lava flow, volcanic plume dynamics, ash cloud dispersio...

Blasting experiments were performed that investigate multiple explosions that occur in quick succession in the ground and their effects on host material and atmosphere. Such processes are known to occur during volcanic eruptions at various depths, lateral locations, and energies. The experiments follow a multi-instrument approach in order to observ...

Maar volcanoes are produced by subsurface phreatomagmatic explosions that can move vertically and laterally during an eruption. Constraining the distances that maar-forming explosions move laterally, and the number of relocations common to these eruptions, is vital for informing hazard scenarios and numerical simulations. This study uses 241 intact...

Maars are volcanic craters surrounded by ejecta rings. The craters are excavated by subsurface explosions, commonly attributed to the interaction of magma and groundwater in phreatomagmatic explosions. Maar craters have a variety of shapes and sizes, but commonly are elongate. This paper explores the relationship between the orientation of maar elo...

A maar is a volcanic crater formed from subsurface phreatomagmatic explosions which produce a distinctive landform for remote morphometric analysis. Ninety one percent of maars with published compositional data are mafic. There is evidence for water and ice on Mars along with volcanic landforms that reflect probable interactions between magma and w...

The behavior of magma as it encounters unconsolidated sediment can be studied in fortuitous exposures of incised volcanic systems to help determine the conditions that control the transport, arrest, or mingling of that magma in the sediment. The Pliocene subaqueous basaltic fissure at 71 Gulch, Idaho, USA contains unusual light-colored glassy mingl...

71 Gulch Volcano, located in the western Snake River Plain, southwestern Idaho (USA), was formed by a basaltic fissure eruption into Pliocene Lake Idaho. Deposits at and below the eruptive surface record the nature of explosive and nonexplosive sediment-magma and water-magma interactions. The paleoenvironment and the volcanic plumbing system of 71...

A 7 km thick section of Oligocene to mid-Miocene Comondú Group arc volcanic, sedimentary, and intrusive rocks is exposed on the Bahía Concepción Peninsula. We created an updated map of the northern peninsula using field observations, petrography, and Google Earth imagery to establish stratigraphic and intrusive relations, from forearc sedimentation...

The Gulf of California is an archetype of continental rupture through transtensional rifting, and exploitation of a thermally weakened arc to produce a rift. Volcanic rocks of central Baja California record the transition from calcalkaline arc magmatism, due to subduction of the Farallon plate (ca. 24–12 Ma), to rift magmatism, related to the openi...

The Diamond Craters of Oregon provide a unique location containing craters of volcanic and collapse origins, which can serve as a terrestrial analog to the surface of Mars. 3-D models produced from Unmanned Aerial Vehicle (UAV) photogrammetry in Diamond Craters allowed for morphometric quantification of the craters. Morphometric perimeters include...

A maar is a volcanic crater formed from magma interaction with groundwater or ice, producing a subsurface explosion. The complexity of maar morphometry reflects complexities of eruption processes and sequences, suggesting changing hazards during an eruptive sequence. Maar shapes have been described in two dimensions in the MaarVLS database. A third...

A maar is a volcanic crater formed from magma interaction with groundwater or ice, producing a subsurface explosion. The complexity of maar morphometry reflects complexities of eruption processes and sequences, suggesting changing hazards during an eruptive sequence. Maar shapes have been described in two dimensions in the MaarVLS database. A third...

We present new structural data from the Bahia Concepción-Peninsula on the Gulf of California margin of Baja California Sur, using detailed mapping of plutonic, volcanic and sedimentary rocks. These are exposed along west-dipping range front normal faults first mapped by McFall in 1968. There, footwall uplift has exposed Cretaceous granitic basement...

Austurfjöll is the largest basaltic glaciovolcanic massif at Askja volcano (Central Iceland), and through detailed studies of its volcanological and geochemical characteristics, we provide a detailed account of the sequence and structure of the ice-confined construction of a large Icelandic basaltic volcano. In particular, Austurfjöll represents a...

Interaction of magma with groundwater or surface water can lead to explosive phreatomagmatic eruptions. Questions of this process center on effects of system geometry and length and time scales, and these necessitate experiments at larger scale than previously conducted in order to investigate the thermohydraulic escalation behavior of rapid heat t...

A maar crater is the top of a much larger subsurface diatreme structure produced by phreatomagmatic explosions and the size and shape of the crater reflects the growth history of that structure during an eruption. Recent experimental and geophysical research has shown that crater complexity can reflect subsurface complexity. Morphometry provides a...

A maar crater is the top of a much larger subsurface diatreme structure produced by phreatomagmatic explosions and the size and shape of the crater reflects the growth history of that structure during an eruption. Recent experimental and geophysical research has shown that crater complexity can reflect subsurface complexity. Morphometry provides a...

Experimental work and field observations have inspired the revision of conceptual models of how maar-diatreme eruptions progress and the effects of variable energy, depth, and lateral position of explosions during an eruption sequence. This study reevaluates natural tephra ring deposits to test these new models against the depositional record. Two...

Recent work is changing our understanding of phreatomagmatic maar-diatreme eruptions and resulting deposits. In previous models, explosions were often inferred to take place only at the base of a diatreme, with progressive downward migration due to a cone of depression in the host aquifer. However, diatremes themselves contain much water that is he...

Eruptions through debris-filled vents produce deposits containing magmatic juvenile lithic and recycled clasts. Recycled clasts are exposed to multiple transportation and fragmentation events. We used experiments with multiple subsurface explosions to track clasts and highlight dominant recycling processes in eruptions through analog debris-filled...

Deposit volume is a critical factor for reconstructing an explosive eruption. Volume estimate models typically used for large Plinian deposits have been adapted and improved repeatedly over the last few decades. Less work has been done to refine a method for estimating the volume from smaller deposits produced by discrete phreatic and phreatomagmat...

While the relationship between the host-substrate properties and the formation of maar-diatreme volcanoes have been investigated in the past, it remains poorly understood. In order to establish the effects of the qualitative host-substrate properties on crater depth, diameter, morphological features, and sub-surface structures, we present a compari...

Any evidence of possible water on Mars gives us a better understanding of what happened on the planet and the possibility of life on Mars. In our research, we are actively looking at processes that happen on Earth and applying them to what we see in the northern polar region of Mars, between 69°N-81°N and 197°E-330°E. Using Context Camera (CTX) dat...

Circumferential variation in sorting, thickness, granulometry, and componentry of tephra ring deposits can result from instabilities in the eruptive jet and interactions with the confining crater. Jet instabilities result in fingers of high particle concentrations that form deposits radiating away from a crater, referred to as rays. Two major types...

Most volcanic explosions leave a crater in the surface around the center of the explosions. Such craters differ from products of single events like meteorite impacts or those produced by military testing because they typically result from multiple, rather than single, explosions. Here we analyze the evolution of experimental craters that were creat...

The volume, grain size, and depositional facies of material deposited outside an explosion crater, ejecta, are sensitive to the depth of the explosion, the explosion energy, and the presence or absence of a crater before the explosion. We detonate buried chemical explosives as an analog for discrete volcanic explosions in experiments to identify un...

We present results of experiments that use small chemical explosive charges buried in layered aggregates to simulate the effects of subsurface hydrothermal and phreatomagmatic explosions at varying depths and lateral locations, extending earlier experimental results that changed explosion locations only along a vertical axis. The focus is on the re...

Subsurface phreatomagmatic explosions can result from the interaction of ascending magma with groundwater. Experiments over a wide range of energies show that for a given energy there is a depth below which an explosion will be contained within the subsurface (not erupt), and there is a corresponding shallower depth that will optimize ejecta disper...

Infrasound and high speed imaging during a series of field-scale buried explosions suggest new details about the generation and radiation patterns of acoustic waves from volcanic eruptions. We recorded infrasound and high speed video from a series of subsurface explosions with differing burial depths and charge sizes. Joint observations and modelin...

Basaltic maar-diatreme volcanoes, which have craters cut into pre-eruption landscapes (maars) underlain by downward-tapering bodies of fragmental material commonly cut by hypabyssal intrusions (diatremes), are produced by multiple subsurface phreatomagmatic explosions. Although many maar-diatremes have been studied, the link between explosion dynam...

Ballistics - bomb-sized pyroclasts that travel from volcanic source to final emplacement position along ballistic trajectories - represent a prime source of volcanic hazard, but their emplacement range, size, and density is useful to inverse model key eruption parameters related to their initial ejection velocity. Models and theory, however, have s...

Detailed analysis of volcanic craters and ballistic deposits can provide insight into eruption dynamics and evolution. As fully exposed craters and associated unmodified deposits are rarely preserved, the dynamics involved can only be inferred. Large-scale blast experiments conducted at the University at Buffalo Geohazards Field Station produced de...

In an ongoing effort to understand the relevant processes behind the formation of volcanic crater-, maar-, and diatreme structures, experiments producing craters with radii exceeding one meter were conducted at University at Buffalos Geohazards Field Station. A chemical explosive was used as energy source for the tests, and detonated in prepared te...

The surface geology of the Northern Volcanic Zone in Iceland is dominated by volcanic ridges, central volcanoes, shield volcanoes, and tuyas. The largest features are typically ice-confined glaciovolcanic in origin, and are overlain by voluminous Holocene subaerial lavas and glacial outwash deposits. The literature has focused heavily on prominent...

Volcanic craters are often formed by multiple subsurface explosions caused by the interaction of magma and groundwater [Lorenz, 1973; Valentine and White, 2012]. To understand the processes and products of such explosions, scientists spent 2 years conducting experiments that produced craters on the meter scale at the Geohazards Field Station in Ash...

Sequences of basaltic pillow lavas that transition upward with systematic gradation from pillow fragment breccias to fluidal bomb-bearing breccias to bomb-bearing lapilli tuffs are common at Askja volcano, Iceland. Based on the detailed textural investigation of three of these sequences, we argue that they record temporally continuous transitions f...

Coherent-Margined Volcaniclastic Dikes (CMVDs) are described for the first time from Askja (Dyngjufjöll), Iceland. These dikes display continuous, coherent glassy margins 5 cm thick and have a variety of clastic interiors comprising vitric tephra, pillow and pillow-fragment bearing lapilli tuffs. CMVDs are interpreted to form when basaltic dikes in...

Transitional sequences of subaqueous pillow basalt through pillow breccia to phreatomagmatic lapilli tuff are common at many subaqueous to emergent volcanic centers. Examples from Askja central volcano illustrate the many possible fragmentation and emplacement mechanisms that characterize such transitions. Askja (Dyngjufjöll) is a predominantly bas...

The Icelandic landscape is dominated by basaltic glaciovolcanic and Holocene post-glacial landforms. The lack of chemical diversity has led to significant simplification of regional maps. This includes areas of historic volcanic activity, such as Askja (Dyngjufjöll) in central Iceland. The purpose of this study is to improve the resolution of the r...

Ice-confined basaltic eruptions produce complex sequences of diverse lava flow types and primary and secondary deposits. While many of these have been described in detail from a variety of centers in Iceland, Canada and Antarctica, the role of intrusions in glaciovolcanic massif construction and evolution is as of yet poorly understood. Dyngjufjöll...

Break-out floods from natural or artificial impoundments are significant hazards in many environments and regions around the world, resulting in loss of life, damage to infrastructure, and dramatic geomorphic changes due to the very high rate of energy expenditure associated with high flow velocities and depths in newly created or underfit pre-exis...

Lahars, and other sudden onset floods, are highly dynamic with temporally and spatially evolving sediment loads. Numerical models of sudden onset flood behaviour, particularly those applied to real world events, have tended to neglect sediment transport processes. This is a serious though perhaps understandable shortcoming given a lack of field mea...

At 20:26 (NZDT) on 25 September 2007 a moderate gas-driven eruption beneath the summit Crater Lake of Mt. Ruapehu, New Zealand generated a directed ballistic fallout apron and surtseyan jet that impacted an area of c. 2.5 km2 to the north of the vent. Two climbers were caught in the blast at a hut 600 m from the vent. Primary, ice-slurry lahars wer...

Mt Ruapehu is New Zealand's most active onshore volcano. In 2007, the volcano produced a large lahar following a break-out from the summit Crater Lake. Here, satellite and airborne remote sensing and image processing is used to extract the path of the lahar using ASTER and SPOT5 visible and near infra-red imagery, ALOS-PALSAR L-band synthetic apert...

Mt. Ruapehu, in the central North Island of New Zealand, is one of the most lahar-prone volcanoes in the world. Since historic observations began in 1861 AD, more than 50 individual lahars have been recorded in the Whangaehu valley alone, the natural outlet to the summit Crater Lake. These lahars have been triggered by a variety of mechanisms, incl...

Sediment load within dilute lahars and other outburst floods is well known to be highly transient. Sediment in transport affects flow hydraulics through density, viscosity and turbulence modification, and exerts rapid landscape change through erosion and deposition. The failure of most previous models of dilute lahars and outburst floods to include...