Episodic inflation and complex surface deformation of Akutan volcano, Alaska revealed from GPS time-series

DeGrandpre, K.; Wang, Teng; Lü, Zhong; Freymueller, J. T.

doi:10.1016/j.jvolgeores.2017.10.003

Cited by 16 publications

(9 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

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

Self Cite

View full text Add to dashboard Cite

show abstract

“…The surface deformation at Semisopochnoi Volcano, observed in the processed interferograms, was analyzed through the inversion of LOS displacement measurements to define the best-fit deformation source parameters for three commonly used geometries (Lee et al, 2006(Lee et al, , 2013Lu et al, 2002Lu et al, , 2003Lu et al, , 2007Lu & Dzurisin, 2010Lu, Masterlark, & Dzurisin, 2005;Masterlark et al, 2012). The latitude, longitude, depth, source geometry, and pressure/volume change for a Mogi point source (Mogi, 1958), Yang spheroid (Yang et al, 1988), and Okada dislocation plane (Okada, 1985) were estimated in Matlab through a nonlinear least squares inversion of Monte Carlo simulations limited by upper and lower bounded input parameters, using the "trust-region-reflective" optimization algorithm to minimize the residual sum of squares (RSS) with an error tolerance of 0.0001 and a maximum of 2,500 iterations for each simulation (DeGrandpre et al, 2017;Lu et al, 2002Lu et al, , 2003Lu et al, , 2007Lu, Masterlark, & Dzurisin, 2005). Residuals are calculated by estimating the three-component displacement (east, north, and vertical) from the forward model predictions for each pixel in the interferogram, converting these directional displacements to LOS displacements, and then subtracting them from the LOS measurement available from every coherent pixel.…”

Section: Inversion Of Surface Deformationmentioning

confidence: 99%

“…Establishing records of an individual volcano's deformation “baseline” with InSAR measurements of the direction, shape, rate, and magnitude of displacement as well as nondeforming periods is essential for hazard mitigation (e.g., Ebmeier et al, ; Lu et al, ; Lu & Dzurisin, , ; Pritchard et al, ; Reath et al, ). Episodes of inflation have been observed to extend through months or even years with rates of 10 s–100 s mm/yr, but the precise nature of the relationship between displacement and parameters that describe eruptive activity has not yet been defined (e.g., DeGrandpre et al, ; Lee et al, ; Lu & Dzurisin, ; Pritchard et al, ). However, surface deformation that exceeds these rates commonly terminates with an eruption, except in cases of large caldera systems, such as Campi Flegrei or Laguna del Maule, where respective inflation rates of up to 90 and 40 cm/yr have been observed (Acocella et al, ; Le Mével et al, ).…”

Section: Introductionmentioning

confidence: 99%

High Rates of Inflation During a Noneruptive Episode of Seismic Unrest at Semisopochnoi Volcano, Alaska in 2014–2015

DeGrandpre

Pesicek

Lü

et al. 2019

Geochem Geophys Geosyst

Self Cite

View full text Add to dashboard Cite

Magma intrusion rate is a key parameter in eruption triggering but is poorly quantified in existing geodetic studies. Here we examine two episodes of rapid inflation in this context. Two noneruptive microseismic swarms were recorded at Semisopochnoi Volcano, Alaska in 2014-2015. We use differential SAR techniques and TerraSAR-X images to document surface deformation from 2011 to 2015, which comprises island-wide radial inflation totaling~25 cm (+/−1 cm) line of sight displacement in 2014-2015. Multiple source geometries are tested in an inversion of the deformation data, and InSAR data are best fit by a spheroid trending to the northeast and plunging to the southeast, with a major axis of~4 km and minor axes of~1 km, directly under the central caldera of Semisopochnoi. In 2014, a modeled influx of 0.043 km 3 of magma caused line of sight displacement of~17 cm. This magma was stored at a depth of~8 km, until 2015 when 0.029 km 3 was added. Along with the definition of inflation source parameters, the recorded seismic events are relocated using differential travel times. These relocated events outline a linear aseismic area within a larger zone of shallow (<10 km) seismicity. This aseismic region aligns with the centroid of the deformation model. Based on these geodetic and seismic models, the plumbing system at Semisopochnoi is interpreted as a spheroidal magma storage zone at a depth of˜8 km below a linear feature of partial melt. The observed deformation and seismicity appear to result from rapid injection into this main storage region.

show abstract

“…Previous studies have shown that a spherical “Mogi” source is sufficient to model the volcanic deformation at Westdahl and Makushin volcanoes (Gong et al, 2015; Lu et al, 2002, 2003; Mann & Freymueller, 2003). Akutan has a more complex magma plumbing system (DeGrandpre et al, 2017), but we found a Mogi source is still sufficient enough for studying the volume change history of Akutan volcano because the largest inflation events were well described by a Mogi source (Text S4). Therefore, we assume Mogi sources that are not moving over time (i.e., the source location is estimated as a constant in time) to represent the pressurized magma chamber producing the surface deformation for all three volcanoes.…”

Section: Methodsmentioning

confidence: 76%

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

Xue

Freymueller

2020

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Episodic inflation and complex surface deformation of Akutan volcano, Alaska revealed from GPS time-series

Cited by 16 publications

References 28 publications

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

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

High Rates of Inflation During a Noneruptive Episode of Seismic Unrest at Semisopochnoi Volcano, Alaska in 2014–2015

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

Contact Info

Product

Resources

About