Seismic evidence for a steeply dipping reflector—stagnant slab in the mantle transition zone

Weber, M.; Wicks, Charles W.; Stunff, Yves Le; Romanowicz, Barbara

doi:10.1093/gji/ggu438

Cited by 7 publications

(3 citation statements)

References 53 publications

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“…This approach has been used in global seismology for the detection and location of heterogeneities in the Earth mantle that cause scattering and/or reflection of seismic waves (e.g. Kaneshima, 2009Kaneshima, , 2016Kaneshima & Helffrich, 2003;Rost et al, 2008;Schumacher & Thomas, 2016;Schumacher et al, 2018;Weber and Wicks, 1996;Weber et al, 2015;Wicks and Weber, 1996;Wright, 1972;Wright & Muirhead, 1969).…”

Section: Resultsmentioning

confidence: 99%

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Mapping lithological boundaries in mines with array seismology and in situ acoustic emission monitoring

Pisconti

Plenkers²,

Philipp³

et al. 2019

Geophysical Journal International

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SUMMARY Knowledge of the position of lithological boundaries is key information for a realistic interpretation of geological settings. Especially in the mining environment, the exact knowledge of geometrical boundaries and characteristics of rock structures has a great impact for both economic decisions and safety awareness. For this purpose, we investigate the P-coda of high frequency acoustic emission (AE) events (picoseismicity) and test the application of array seismology techniques, usually used to study the Earth's deep interior, on a much smaller scale in a mining environment. In total 52 events were used, all of them recorded in the Asse II salt mine in Lower Saxony (Germany) using a network of 16 piezoelectric sensors. Many of these events show a pulse-like arrival in the late P-coda, suggesting the presence of a well-defined structure which scatters seismic energy. To explore the directional information of the signals in the seismograms we use the sliding-window slowness-backazimuth analysis, performed on the waveform envelope of the entire recording. Strong direct P-wave arrivals are clearly visible with observed slowness and backazimuth as expected for a homogenous medium. This implies straight ray paths from event to sensors indicating that the medium between the events and the sensors is homogeneous for wavelengths larger than about 60 cm. In the late P-coda we observe out-of-plane arrivals from southeast and, assuming single P-to-P scattering, we find that the scatterers responsible for these observations are clustered in space defining a sharp reflector corresponding to a known lithological boundary located at the southern flank of the salt dome. In agreement with the established geological model we observe no other dominant reflections in the analysed waveforms that would indicate previously unknown lithological boundaries. This study shows that array seismology can be applied to AEs in mines to gain more information on structures and heterogeneities located in the vicinity of the monitored rock volume. In micro-acoustically monitored mines, this technique could be a valuable addition to increase hazard awareness and mining efficiency at little or no extra costs.

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Section: Resultsmentioning

confidence: 99%

“…allow us to use and analyze the S-coda as an independent proof of the imaged reflector as shown by Weber and Wicks, (1996) and Weber et al (2015) for the detections of heterogeneities at the larger scale of the Earth's mantle. S-to-S reflections would arrive at travel time of at least 35 ms, while our recording last 32.768 ms.…”

Section: Discussionmentioning

confidence: 99%

Mapping lithological boundaries in mines with array seismology and in situ acoustic emission monitoring

Pisconti

Plenkers²,

Philipp³

et al. 2019

Geophysical Journal International

View full text Add to dashboard Cite

show abstract

“…Recently, Weber et al [2015] challenged the interpretation of Kaneshima and Helffrich [1998]. Using events #7, 10, 12, and two more recent events, they suggested the presence of a reflector near 400 km depth, instead of the scatterer K2 located around 1600 km depth (which probably corresponds to the scatterer #27 in Table 2).…”

Section: 1002/2015jb012432mentioning

confidence: 99%

Constraining the geometries of small‐scale heterogeneities: A case study from the Mariana region

Korenaga

2015

JGR Solid Earth

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A new array‐based method for seismic waveform data is developed to detect small‐scale heterogeneities in the mantle and constrain their possible locations and sizes. Detecting small‐scale heterogeneities using scattered waves has been challenging because scattered phases usually suffer from low signal‐to‐noise ratios, and determining the shapes of such heterogeneities is even more difficult because of isochronal artifacts. In the proposed method, the problem of the low signal‐to‐noise ratio is addressed by adopting dual bootstrap stacking, which can detect weak signals even with a limited number of seismic traces, as well as by ensuring reproducibility among multiple events. The locations of detected scatterers and their sizes and shapes are then estimated using a new kind of hierarchical cluster analysis that could minimize the effect of isochronal artifacts. The new method is applied to a previously analyzed data set of Mariana earthquakes to facilitate a comparison with conventional methods. In the middle to lower mantle beneath the Mariana Trench region, a total of 39 scatterers are identified via S‐to‐P scattering, with their potential volumes ranging from <8 × 104 to ∼1 × 106 km3.

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Effects of Fe-Ca-Mg substitutions on the equation-of-state of pyrope-rich garnet from ab initio modeling and experiments: Insights and implications for the upper mantle

Núñez-Valdez,

Satta,

Speziale

2024

Physics of the Earth and Planetary Interiors

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Seismic evidence for a steeply dipping reflector—stagnant slab in the mantle transition zone

Abstract: . (2015): Seismic evidence for a steeply dipping reflector--stagnant slab in the mantle transition zone.

Cited by 7 publications

References 53 publications

Mapping lithological boundaries in mines with array seismology and in situ acoustic emission monitoring

Mapping lithological boundaries in mines with array seismology and in situ acoustic emission monitoring

Constraining the geometries of small‐scale heterogeneities: A case study from the Mariana region

Effects of Fe-Ca-Mg substitutions on the equation-of-state of pyrope-rich garnet from ab initio modeling and experiments: Insights and implications for the upper mantle

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