Episodic inflation events at Akutan Volcano, Alaska, during 2005–2017

Ji, Kang Hyeun; Yun, Sang‐Ho; Rim, Hyoungrea

doi:10.1002/2017gl074626

Cited by 15 publications

(11 citation statements)

References 29 publications

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“…Akutan volcano has shown multiple episodic inflation events that have occurred approximately every 2-3 years (Figure 2b). The inflation events in 2008,2011,2014, and 2016 already were identified by previous studies (DeGrandpre et al, 2017;Ji et al, 2017;Ji & Herring, 2011), and the estimated volume increase of each event is consistent with the previous results. We also find two earlier events that happened in 2004 and 2006, when only the AVO continuous GPS sites were operational, and an inflation event that has been ongoing since 2019.…”

Section: Resultssupporting

confidence: 91%

A 25‐Year History of Volcano Magma Supply in the East Central Aleutian Arc, Alaska

Xue

Freymueller

2020

Geophysical Research Letters

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Using ~25 years of GPS and InSAR observations and the time‐dependent inversion filter, we invert for the volume change history of three active volcanoes in the east central Alaska Aleutian arc and the secular velocity of the region. The inferred time‐dependent volume change shows (1) two exponentially decaying pulses followed by a nearly linear inflation period at Westdahl volcano, (2) multiple episodic inflation events at Akutan volcano, and (3) transient volcanic inflation and long‐term deflation signals at Makushin volcano. Comparing our regional velocity estimates with recently published block models, we find a small signal that can be explained by slip deficit on the megathrust, either from a shallow (<20 km depth) almost fully locked zone or a weakly locked zone confined to 25–50 km depth.

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Section: Resultssupporting

confidence: 91%

A 25‐Year History of Volcano Magma Supply in the East Central Aleutian Arc, Alaska

Xue

Freymueller

2020

Geophysical Research Letters

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“…For example, before its 2010 eruption, repeated episodes of magma intrusion and accumulation were found beneath Eyjafjallajökull, Iceland (Sigmundsson et al, 2010). In the Aleutian arc, multiple episodic inflation events have been observed at Akutan volcano from 2005 to 2017 (DeGrandpre et al, 2017;Ji et al, 2017). Episodic inflation events are common at Kilauea volcano in Hawaii as well (e.g., Cervelli & Miklius, 2003); in that case, episodic deflation-inflation events were interpreted to result from short-lived blockages in the magma supply.…”

Section: Magma Supply Dynamicsmentioning

confidence: 99%

Modeling the Posteruptive Deformation at Okmok Based on the GPS and InSAR Time Series: Changes in the Shallow Magma Storage System

2020

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Based on the unscented Kalman filter, we develop a time‐dependent inversion filter combining Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) time series observations for modeling volcano deformation. We use the Variance Component Estimation method as means to assign the relative weights for GPS and InSAR data. Then we use the inversion filter to model the posteruptive deformation at Okmok volcano, Alaska. We find that a Mogi source at 3–4 km depth fits the InSAR data well, while the best fit to the GPS data is an oblate spheroid source at about 2.5 km depth. Our final model consists of a shallow sill at ~0.9 km and a Mogi source at ~3.2 km depth, which well fit both the GPS and InSAR data simultaneously. We think the Mogi source obtained here is the same source account for the preeruptive deformation. The shallow sill is a new structure that was not seen before the 2008 eruption. From 2008 to 2019, we have observed five inflation episodes, each of which decays exponential in time. We find that the characteristic timescale of those inflation episodes decreases with respect to time. The total volume change from the two sources is 0.068 km3, which recovers 50–60% of the volume decrease during the 2008 eruption.

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“…Real-time geophysical monitoring is a fundamental tool for tracking and understanding volcanic activity and real-time hazard assessment (e.g., Scarpa and Tilling, 1996;Sparks et al, 2012;Ji et al, 2017). In the aftermath of Iceland's Ejafyallajokull eruption of 2010 numerous working groups and think-tanks (Wotawa and Stohl, 2012;Bonadonna, 2014;Brenot et al, 2014) identified real-time tracking of particle size distribution (PSD), in synergy with plume modeling, as a fundamental need for improved hazard assessment and effective management of volcanic crises.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Geophysical Monitoring of Particle Size Distribution During Volcanic Explosions at Stromboli Volcano (Italy)

Pioli

Harris

2019

Front. Earth Sci.

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Of all the key parameters needed to inform forecast models for volcanic plumes, real-time tracking particle size distribution (PSD) of pyroclasts leaving the vent coupled with plume modeling has probably the highest potential for effective management of volcanic hazard associated with plume dispersal and sedimentation. This paper presents a novel algorithm capable of providing syn-emission horizontal size and velocity of particles in real time, converted in mass discharge rates, and its evolution during an explosion, using thermal infrared videos. We present data on explosions that occurred at the SW crater of Stromboli volcano (Italy) in 2012. PSDs and mass eruption rate (MER) data, collected at frequencies of 40 Hz, are then coupled with particle and gas speed data collected with traditional image analysis techniques. The dataset is used to quantify for the first time the dynamics of the explosions and the regime of magma fragmentation. We find that explosive evacuation of magma from a Strombolian conduit during a single explosion proceeds at a constant rate while the explosive dynamics are marked by a pattern that includes an initial transient and short phase until the system stabilizes at equilibrium. These stationary conditions dominate the emission. All explosions begin with a gas jet (onset phase), with maximum recorded vertical velocities above 150 m/s. These high velocities are for small particles carried by the faster moving gas or pressure wave, and larger particles typically have slower velocities. The gas jets are followed by a particle-loaded plume. The particles increase in number until the explosion dynamics become almost constant (in the stationary phase). MER is either stable or increases during the onset to become stable in the stationary phase. The shearing at the interface between the magma and the gas jets controls fragmentation dynamics and particles sizes. Quantification of the Reynolds and Weber numbers suggests that the fragmentation regime changes during an explosion to affect particle shape. The algorithm proposed requires low-cost thermal monitoring systems, and low processing capability, but is robust, powerful, and accurate and is able to provide data with unprecedented accuracy. In general terms, its applicability is limited by the size of individual pixels recorded by the camera, which depends on the detector, the recording distance, and the optical system, particle temperature, which has to be significantly higher than the background.

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Episodic inflation events at Akutan Volcano, Alaska, during 2005–2017

Cited by 15 publications

References 29 publications

A 25‐Year History of Volcano Magma Supply in the East Central Aleutian Arc, Alaska

A 25‐Year History of Volcano Magma Supply in the East Central Aleutian Arc, Alaska

Modeling the Posteruptive Deformation at Okmok Based on the GPS and InSAR Time Series: Changes in the Shallow Magma Storage System

Real-Time Geophysical Monitoring of Particle Size Distribution During Volcanic Explosions at Stromboli Volcano (Italy)

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