scholarly journals Shear wave reflectivity imaging of the Nazca-South America subduction zone: Stagnant slab in the mantle transition zone?

2012 ◽  
Vol 39 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Sean Contenti ◽  
Yu Jeffrey Gu ◽  
Ahmet Ökeler ◽  
Mauricio D. Sacchi
Keyword(s):  
South America ◽  
Subduction Zone ◽  
Transition Zone ◽  
Shear Wave ◽  
Mantle Transition Zone ◽  
Stagnant Slab ◽  
Reflectivity Imaging

scholarly journals Seismic waveform tomography of the central and eastern Mediterranean upper mantle

Solid Earth ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 669-690 ◽  
Author(s):  
Nienke Blom ◽  
Alexey Gokhberg ◽  
Andreas Fichtner
Keyword(s):  
Subduction Zone ◽  
Transition Zone ◽  
Upper Mantle ◽  
High Velocity ◽  
Eastern Mediterranean ◽  
Crust And Upper Mantle ◽  
Mantle Transition Zone ◽  
Seismic Waveform ◽  
Waveform Tomography ◽  
Seismic Waveform Tomography

Abstract. We present a seismic waveform tomography of the upper mantle beneath the central and eastern Mediterranean down to the mantle transition zone. Our methodology incorporates in a consistent manner the information from body and multimode surface waves, source effects, frequency dependence, wavefront healing, anisotropy and attenuation. This allows us to jointly image multiple parameters of the crust and upper mantle. Based on the data from ∼ 17 000 unique source–receiver pairs, gathered from 80 earthquakes, we image radially anisotropic S velocity, P velocity and density. We use a multi-scale approach in which the longest periods (100–150 s) are inverted first, broadening to a period band of 28–150 s. Thanks to a strategy that combines long-period signals and a separation of body and surface wave signals, we are able to image down to the mantle transition zone in most of the model domain. Our model shows considerable detail in especially the northern part of the domain, where data coverage is very dense, and displays a number of clear and coherent high-velocity structures across the domain that can be linked to episodes of current and past subduction. These include the Hellenic subduction zone, the Cyprus subduction zone and high-velocity anomalies beneath the Italian peninsula and the Dinarides. This model is able to explain data from new events that were not included in the inversion.

Mantle transition zone input to kimberlite magmatism near a subduction zone: Origin of anomalous Nd–Hf isotope systematics at Lac de Gras, Canada

2013 ◽  
Vol 371-372 ◽  
pp. 235-251 ◽  
Author(s):  
Sebastian Tappe ◽  
D. Graham Pearson ◽  
Bruce A. Kjarsgaard ◽  
Geoff Nowell ◽  
David Dowall
Keyword(s):  
Subduction Zone ◽  
Transition Zone ◽  
Hf Isotope ◽  
Mantle Transition Zone ◽  
Isotope Systematics
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