Radar Altimetry as a Robust Tool for Monitoring the Active Lava Lake at Erebus Volcano, Antarctica
6
Citation
30
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract The level of lava within a volcanic conduit reflects the overpressure within a connected magma reservoir. Continuous monitoring of lava level can therefore provide critical insights into volcanic processes and aid hazard assessment. However, accurate measurements of lava level are not easy to make, partly owing to the often dense fumes that hinder optical techniques. Here we present the first radar instrument designed for the purpose of monitoring lava level and report on its successful operation at Erebus volcano, Antarctica. We describe the hardware and data‐processing steps followed to extract a time series of lava lake level, demonstrating that we can readily resolve ∼1 m cyclic variations in lake level that have previously been recognized at Erebus volcano. The performance of the radar (continuous, automated data collection in temperatures of around −30 °C) indicates the suitability of this approach for sustained automated measurements at Erebus and other volcanoes with lava lakes.Keywords:
Lava dome
Lava field
Volcanic hazards
Stratovolcano
The structures and textures preserved in lava domes reflect underlying magmatic and eruptive processes, and may provide evidence of how eruptions initiate and evolve. This study explores the remarkable cycles in lava extrusion style produced between 1922 and 2012 at the Santiaguito lava dome complex, Guatemala. By combining an examination of eruptive lava morphologies and textures with a review of historical records, we aim to constrain the processes responsible for the range of erupted lava type and morphologies. The Santiaguito lava dome complex is divided into four domes (El Caliente, La Mitad, El Monje, El Brujo), containing a range of proximal structures (e.g. spines) from which a series of structurally contrasting lava flows originate. Vesicular lava flows (with a'a like, yet non-brecciated flow top) have the highest porosity with interconnected spheroidal pores and may transition into blocky lava flows. Blocky lava flows are high volume and texturally variable with dense zones of small tubular aligned pore networks and more porous zones of spheroidal shaped pores. Spines are dense and low volume and contain small skeletal shaped pores, and subvertical zones of sigmoidal pores. We attribute the observed differences in pore shapes to reflect shallow inflation, deflation, flattening or shearing of the pore fraction. Effusion rate and duration of the eruption define the amount of time available for heating or cooling, degassing and outgassing prior to and during extrusion, driving changes in pore textures and lava type. Our new textural data when reviewed with all the other published data allows cyclic models to be developed. The cyclic eruption models are influenced by viscosity changes resulting from (1) initial magmatic composition and temperature, and (2) effusion rate which in turn affects degassing, outgassing and cooling time in the conduit. Each lava type presents a unique set of hazards and understanding the morphologies and dome progression is useful in hazard forecasting.
Lava dome
Lava field
Effusive eruption
Shield volcano
Dome (geology)
Cite
Citations (42)
During eruptive activity of andesitic stratovolcanoes, the extrusion of lava domes, their collapse and intermittent explosions are common volcanic hazards. Many lava domes grow in a preferred direction, in turn affecting the direction of lava flows and pyroclastic density currents. Access to active lava domes is difficult and hazardous, so detailed data characterising lava dome growth are typically limited, keeping the processes controlling the directionality of extrusions unclear. Here we combine TerraSAR-X satellite radar observations with high-resolution airborne photogrammetry to assess morphological changes, and perform finite element modelling to investigate the impact of loading stress on shallow magma ascent directions associated with lava dome extrusion and crater formation at Volcán de Colima, México. The TerraSAR-X data, acquired in ~1-m resolution spotlight mode, enables us to derive an accurate chronology of the eruptive processes from intensity-based time-lapse observations of the general crater and dome evolution. The satellite images are complemented by close-range airborne photos, processed by the Structure-from-Motion workflow. This allows the derivation of high-resolution digital elevation models, providing insight into detailed loading and unloading features. During the observation period from Jan-2013 to Feb-2016, we identify a dominantly W-directed dome growth and lava flow production until Jan-2015. In Feb-2015, following the removal of the active summit dome, the surface crater widened and elongated along a NE-SW axis. Later in May-2015, a new dome grew towards the SW of the crater while a separate vent developed in the NE of the crater, reflecting a change in the direction of magma ascent and possible conduit bifurcation. Finite element models show a significant stress change in agreement with the observed magma ascent direction changes in response to the changing surface loads, both for loading (dome growth) and unloading (crater forming excavation) cases. These results allow insight into shallow dome growth dynamics and the migration of magma ascent in response to changing volcano summit morphology. They further highlight the importance of detailed volcano summit morphology surveillance, as changes in direction or location of dome extrusion may have major implications regarding the directions of potential volcanic hazards, such as pyroclastic density currents generated by dome collapse.
Lava dome
Dome (geology)
Stratovolcano
Cite
Citations (22)
The Mount Meager Volcanic Complex (Mount Meager) is a glacier-clad stratovolcanic system in southwestern British Columbia which last erupted over 2400 years ago (VEI 4). While this is Canada's most recent major explosive eruption, most past research on Mount Meager has focused on its numerous and large volume landslides and thus the volcanic hazard characteristics remain understudied. Here we present a suite of scenario-based hazard maps and an assessment addressing a range of potential future explosive eruptions and associated hazards. In order to overcome limited knowledge of the eruptive history, numerical models have been used to simulate the primary syneruptive hazards of concern (dome-collapse pyroclastic density currents, lahars and tephra fallout) largely utilizing eruption parameters from analogous volcanoes, i.e., glacier-clad stratovolcanoes in a subduction zone setting. This study provides a framework for similar volcanic hazard studies where geologic data is limited, funds are minimal, and access is difficult. Furthermore, this sets the stage for recognizing volcanic hazards in the Canadian landscape, providing a resource to prepare for and mitigate potential impacts well in advance of a crisis situation.
Mount
Volcanic hazards
Cite
Citations (16)
Lava dome
Dome (geology)
Volcanic hazards
Basaltic andesite
Cite
Citations (74)
Meter‐scale DSL‐120 sonar mapping and coregistered Argo II photographic observations reveal changes in eruptive style that closely follow the third‐order structural segmentation of the ridge axis on the southern East Pacific Rise, 17°11′–18°37′S. Near segment ends we observe abundant basaltic lava domes which average 20 m in height and 200 m in basal diameter and have pillow lava as the dominant lava morphology. The ubiquity of pillow lava suggests low effusion rate eruptions. The abundance of lava domes suggests that the fissure eruptions were of sufficient duration to focus and produce a line of volcanic edifices. Near segment centers we observe fewer but larger lava domes, voluminous drained and collapsed lava lakes, and smooth lobate and sheet lava flows with very little pillow lava. The abundance of sheet flows suggests that high effusion rate eruptions are common. Fewer lava domes and large lava lakes suggest that fissure eruptions do not focus to point sources. This pattern was observed on eight third‐order ridge segments suggesting that a fundamental volcanic segmentation of the ridge occurs on this scale. The third‐order segment boundaries also correlate with local maxima in the seismic axial magma chamber reflector depth throughout the study area and decreased across‐axis width of the region of seismic layer 2A thickening along the one segment where sufficient cross‐axis seismic lines exist. The geochemically defined magmatic segment boundaries in the study area match the locations of our volcanic segment boundaries, although rock sampling density is not adequate to constrain the variation across all the third‐order volcanic segments that we identify. These observations suggest that variation in the processes of crustal accretion along axis occurs at a length scale of tens of kilometers on superfast spreading (>140 km/Myr full rate) mid‐ocean ridges.
Lava field
Lava dome
Effusive eruption
Pillow lava
Volcanic plateau
Cite
Citations (76)
Caldera
Lava dome
Dome (geology)
Stratovolcano
Magma chamber
Cite
Citations (10)
Silicic Lava Domes.- Regularities in Growth of the Mount St. Helens Dacite Dome 1980-1986.- The Development and Distribution of Surface Textures at the Mount St. Helens Dome.- Lava Domes Modeled as Brittle Shells that Enclose Pressurized Magma, with Application to Mount St. Helens.- A Model for Dome Eruptions at Mount St. Helens, Washington Based on Subcritical Crack Growth.- Viscoplastic Models of Lava Domes.- Mafic Lava Flow.- Surfaces of Aa Flow-Fields on Mount Etna, Sicily: Morphology, Rheology, Crystallization and Scaling Phenomena.- Longitudinal Variations in Rheological Properties of Lavas: Puu Oo Basalt Flows, Kilauea Volcano, Hawaii.- Numerical Simulation of Lava Flows on Some Volcanoes in Japan.- On the Mechanisms of Lava Flow Emplacement and Volcano Growth: Arenal, Costa Rica.
Lava dome
Stratovolcano
Silicic
Dome (geology)
Cite
Citations (113)
Lava field
Lava dome
Scoria
Effusive eruption
Volcanic hazards
Cite
Citations (36)
Lava dome
Stratovolcano
Dome (geology)
Lineament
Cite
Citations (45)
Stratovolcano
Dacite
Lava dome
Phreatic eruption
Dome (geology)
Cite
Citations (9)