scholarly journals One-Sided Joint Inversion of Shear Velocity and Resistivity from the PI-LAB Experiment at the Equatorial Mid-Atlantic Ridge

2021 ◽  
Author(s):  
Nicholas Harmon ◽  
Shunguo Wang ◽  
Catherine A. Rychert ◽  
Steven Constable ◽  
John-Michael Kendall
Keyword(s):  
Joint Inversion ◽  
Shear Velocity ◽  
Lab Experiment ◽  
Mid Atlantic Ridge

scholarly journals Sediment Characterization at the Equatorial Mid‐Atlantic Ridge From P ‐to‐ S Teleseismic Phase Conversions Recorded on the PI‐LAB Experiment

2018 ◽  
Vol 45 (22) ◽  
pp. 12,244-12,252 ◽  
Author(s):  
M. R. Agius ◽  
N. Harmon ◽  
C. A. Rychert ◽  
S. Tharimena ◽  
J.‐M. Kendall
Keyword(s):  
Lab Experiment ◽  
Mid Atlantic Ridge

A new crustal shear-velocity model in Southwest China from joint seismological inversion and its implications for regional crustal dynamics

2019 ◽  
Author(s):  
Yan Yang ◽  
Huajian Yao ◽  
Hanxiao Wu ◽  
Ping Zhang ◽  
Maomao Wang
Keyword(s):  
Tibetan Plateau ◽  
Rayleigh Wave ◽  
Joint Inversion ◽  
Shear Velocity ◽  
P Wave ◽  
Tectonic Deformation ◽  
Inversion Method ◽  
Low Velocity ◽  
Sw China ◽  
S Period

SUMMARY Southwest (SW) China is located in a transition site from the active Tibetan Plateau to the stable Yangtze craton, which has complicated tectonic deformation and severe seismic hazards. We combine data from ambient noise, teleseismic body and surface waves, and petroleum wells to better constrain the crustal shear-velocity structure in SW China. We jointly invert the Rayleigh wave dispersion (5–40 s period), Rayleigh wave ZH ratio (20–60 s period), and P-wave receiver function for 114 permanent stations with a stepwise linearized joint inversion method. Compared to previous tomography results, we observe higher shear velocity in the sedimentary rocks within the Sichuan Basin, which is consistent with sonic logging measurements. Our model reveals widespread low-velocity zones in the mid-lower crust, and their boundaries correlate well with major fault systems. Between two main mid-crustal low-velocity channels, a prominent high-velocity region surrounded by earthquakes is observed in the inner zone of the Emeishan large igneous province (ELIP) and around the Anninghe-Zemuhe fault zone. These observations are comparable to regional tomography results using very dense arrays. Based on the results, we suggest that mid-lower crustal ductile flow and upper-crustal rigid fault movement play equally important roles in controlling the regional deformation styles and earthquake distribution in SW China. Our results also resolve thick crust-mantle transition zones beneath the eastern Tibetan Plateau and the inner zone of the ELIP due to ‘top-down’ and ‘bottom-up’ crust-mantle interactions, respectively. Our new model can serve as a reference crustal model of future high resolution model construction in SW China.

scholarly journals Triggering of Microseismicity During Low Tides at the Equatorial Mid-Atlantic Ridge, Inferred from the PI-LAB Experiment Data

2021 ◽  
Author(s):  
Konstantinos Leptokaropoulos ◽  
Nicholas Harmon ◽  
Stephen Hicks ◽  
Catherine Rychert ◽  
David Schlaphorst ◽  
...  
Keyword(s):  
Lab Experiment ◽  
Experiment Data ◽  
Mid Atlantic Ridge

scholarly journals Sediment structure at the equatorial mid-atlantic ridge constrained by seafloor admittance using data from the PI-LAB experiment

2020 ◽  
Vol 41 (1) ◽  
Author(s):  
Utpal Saikia ◽  
Catherine Rychert ◽  
Nicholas Harmon ◽  
J. M. Kendall
Keyword(s):  
Lab Experiment ◽  
Sediment Structure ◽  
Mid Atlantic Ridge ◽  
Using Data

Radial anisotropy in Europe from surface waves ambient noise tomography and transdimensional hierarchical inversion

2020 ◽  
Author(s):  
Chloé Alder ◽  
Eric Debayle ◽  
Thomas Bodin ◽  
Anne Paul ◽  
Laurent Stehly ◽  
...  
Keyword(s):  
Group Velocity ◽  
Shear Wave ◽  
Rayleigh Waves ◽  
3D Model ◽  
Joint Inversion ◽  
Shear Velocity ◽  
Dispersion Curves ◽  
Uppermost Mantle ◽  
Radial Anisotropy ◽  
Anisotropy Model

<p>We present a 3D probabilistic model of shear wave velocity and radial anisotropy of the European crust and uppermost mantle mainly focusing on the Alps and the Apennines.</p><p>The model is built using continuous seismic noise recorded between 2010 and 2018 at 1521 broadband stations, including the AlpArray network (Hetényi et al., 2018).</p><p>We use a large dataset of more than 730 000 couples of stations representing as many virtual source-receiver pairs. For each path, we calculate the cross-correlation of continuous vertical- and transverse-components of the noise records in order to get the Green’s function. From the Green’s function, we then obtain the group velocity dispersion curves of Love and Rayleigh waves in the period range 5 to 149 s.</p><p>Our 3D model is built in two steps. First, the dispersion data are used in a linearized least square inversion providing 2D maps of group velocity in Europe at each period. These maps are obtained using the same coverage for Love and Rayleigh waves. Dispersion curves for both Love and Rayleigh waves are then extracted from the maps, at each geographical point. In a second step, these curves are jointly inverted to depth for shear velocity and radial anisotropy. The inversion in done within a Bayesian Monte-Carlo framework integrating some a priori information coming either from PREM (Dziewonski and Anderson 1961) or the recent 3D shear wave model of Lu et al. 2018 performed for the same region.</p><p>Therefore, this joint inversion of Rayleigh and Love data allows us to derive a new 3D model of shear velocity and radial anisotropy of the European crust and uppermost mantle. The isotropic part of our model is consistent with the shear velocity model of Lu et al. 2018. The 3D radial anisotropy model of the region adds new constraints on the deformation of the lithosphere in Europe. Here we present and discuss this new radial anisotropy model, with particular emphasis on the Apennines.</p>

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