The Katla volcanic system imaged using local earthquakes recorded with a temporary seismic network

Jeddi, Zeinab; Tryggvason, Ari; Guðmundsson, Ólafur

doi:10.1002/2016jb013044

Cited by 13 publications

(16 citation statements)

References 63 publications

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“…2d and 3 in map-view section. A similar pattern with a dome-shaped seismicity as well as vertical and elongated seismic clusters has also been observed at the Katla volcano using a continuous 2.5-year passive seismic experiment 37 .…”

Section: Resultssupporting

confidence: 77%

Hydrothermal fluid flow triggered by an earthquake in Iceland

Geoffroy

Dorbath

Ágústsson

et al. 2022

Commun Earth Environ

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Microearthquake hypocenters were analyzed in the Krýsuvík geothermal area in SW-Iceland with data taken from two consecutive passive seismic surveys, 2005 and 2009. Five years prior to the 2005 survey, this area was struck by an earthquake initiating a major top-to-bottom fluid migration in the upper crust. We observe from our surveys a complex bottom-to-top migration of seismicity with time following this fluid penetration, suggesting the migration of a pore pressure front controlled by the upper-crust fracture system. We interpret these data as the time and space development of high-temperature hydrothermal cells from a deep upper crustal fluid reservoir in the supercritical field. These results provide an insight into the coupling mechanisms between active tectonics and fluid flow in upper-crustal extensional systems with high thermal flux.

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Section: Resultssupporting

confidence: 77%

Hydrothermal fluid flow triggered by an earthquake in Iceland

Geoffroy

Dorbath

Ágústsson

et al. 2022

Commun Earth Environ

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“…A more recent experiment using LET did not have good enough resolution to confirm these results (Jonsdottir et al, 2007). Jeddi et al (2016) used a denser earthquake dataset and combined it with the active source data from Gudmundsson et al (1994) to perform joint ASTT/ LET. They found velocities of 3.5 km/s-4.0 km/s beneath the caldera, suggesting a smaller but still significant amount of melt.…”

Section: Katlamentioning

confidence: 99%

Advances in seismic imaging of magma and crystal mush

et al. 2022

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Seismic imaging methods have provided detailed three-dimensional constraints on the physical properties of magmatic systems leading to invaluable insight into the storage, differentiation and dynamics of magma. These constraints have been crucial to the development of our modern understanding of magmatic systems. However, there are still outstanding knowledge gaps resulting from the challenges inherent in seismic imaging of volcanoes. These challenges stem from the complex physics of wave propagation across highly heterogeneous low-velocity anomalies associated with magma reservoirs. Ray-based seismic imaging methods such as travel-time and surface-wave tomography lead to under-recovery of such velocity anomalies and to under-estimation of melt fractions. This review aims to help the volcanologist to fully utilize the insights gained from seismic imaging and account for the resolution limits. We summarize the advantages and limitations of the most common imaging methods and propose best practices for their implementation and the quantitative interpretation of low-velocity anomalies. We constructed and analysed a database of 277 seismic imaging studies at 78 arc, hotspot and continental rift volcanoes. Each study is accompanied by information about the seismic source, part of the wavefield used, imaging method, any detected low-velocity zones, and estimated melt fraction. Thirty nine studies attempted to estimate melt fractions at 22 different volcanoes. Only five studies have found evidence of melt storage at melt fractions above the critical porosity that separates crystal mush from mobile magma. The median reported melt fraction is 13% suggesting that magma storage is dominated by low-melt fraction crystal mush. However, due to the limits of seismic resolution, the seismological evidence does not rule out the presence of small (<10 km3) and medium-sized (<100 km3) high-melt fraction magma chambers at many of the studied volcanoes. The combination of multiple tomographic imaging methods and the wider adoption of methods that use more of the seismic wavefield than the first arriving travel-times, promise to overcome some of the limitations of seismic tomography and provide more reliable constraints on melt fractions. Wider adoption of these new methods and advances in data collection are needed to enable a revolution in imaging magma reservoirs.

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“…These applications are mainly based on active sources. When the source locations of local earthquakes are estimated (Jeddi et al, ; Kissling et al, ; Miller & Smit, ), MVA can also be used on local earthquakes data. Furthermore, because the velocity analysis is a critical step for seismic processing and interpretation, it is necessary to consider efficiency.…”

Section: Introductionmentioning

confidence: 99%

Wave‐Equation Migration Velocity Analysis Using Radon‐Domain Common‐Image Gathers

Liu

2020

JGR Solid Earth

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The accuracy of the background velocity analysis is critical to image the subsurface structure in seismology. Wave‐equation migration velocity analysis using source‐domain common‐image gathers requires picking the relative moveouts based on semblance analysis. However, the picking process is complex and time‐consuming. To avoid picking and maintain efficiency in generating CIGs, an automatic wave‐equation migration velocity analysis method is proposed utilizing the focusing properties of the Radon‐domain common‐image gathers. Seismic events in the Radon‐domain common‐image gathers appear focused if an accurate migration velocity model is used; otherwise, the resultant events will be unfocused. The objective function is defined in the Radon domain to measure focus of the common‐image gathers automatically. The proposed migration velocity analysis method links the defocusing information to the migration velocity update under the assumption that model perturbations only result in slope shifts in the common‐image gathers. This method provides a reasonably accurate background velocity model for imaging and full‐waveform inversion without requiring an accurate initial velocity model. Tests on synthetic and field data demonstrate the effectiveness of the method. This method is tolerable to both inaccurate initial velocity models and the lack of low‐frequency data.

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The Katla volcanic system imaged using local earthquakes recorded with a temporary seismic network

Cited by 13 publications

References 63 publications

Hydrothermal fluid flow triggered by an earthquake in Iceland

Hydrothermal fluid flow triggered by an earthquake in Iceland

Advances in seismic imaging of magma and crystal mush

Wave‐Equation Migration Velocity Analysis Using Radon‐Domain Common‐Image Gathers

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