A joint analysis of the S-wave in the π+π− and π0π0 data

EPJ direct ◽  
2002 ◽  
Vol 4 (1) ◽  
pp. 1-23 ◽  
Author(s):  
R. Kaminski ◽  
L. Lesniak ◽  
K. Rybicki
Keyword(s):  
2021 ◽  
Author(s):  
Nils-Peter Finger ◽  
Mikhail K. Kaban ◽  
Magdala Tesauro ◽  
Walter D. Mooney ◽  
Maik Thomas

<p>The presented model describes the lithospheric state of the cratonic regions of Africa in terms of temperature, density and composition based on joint analysis of gravity and seismic data. In addition, a new model of depth to the Moho was calculated from available seismic data. It was then used in combination with data on topography, sediments, and deep mantle anomalies to obtain residual mantle gravity and residual topography. These residual fields were corrected for thermal effects based on S-wave tomography and mineral physics constraints, assuming a juvenile mantle. Afterwards, the thermally corrected fields are jointly inverted to uncover potential compositional density variations. Following the isopycnic hypothesis, negative variations in cratonic areas are interpreted to be caused by iron depletion. Adapting the initially juvenile mantle composition allows to iteratively improve the thermal and compositional variations, culminating in a self-consistent model of the African lithosphere. Deep depleted lithospheric roots exist under the Westafrican, northern to central Congo, and Zimbabwe Cratons. The temperatures in these areas range from below 800 °C at 100 km depth to 1200 °C at 200 km depth. Higher temperatures and absence of depletion at depths below 100 km in wide areas of the eastern to southern Congo and the Kaapvaal Cratons indicate a thinner and strongly reworked lithosphere.</p>


Geophysics ◽  
2016 ◽  
Vol 81 (5) ◽  
pp. V379-V385 ◽  
Author(s):  
Gabriel Gribler ◽  
Lee M. Liberty ◽  
T. Dylan Mikesell ◽  
Paul Michaels

Estimates of S-wave velocity with depth from Rayleigh-wave dispersion data are limited by the accuracy of fundamental and/or higher mode signal identification. In many scenarios, the fundamental mode propagates in retrograde motion, whereas higher modes propagate in prograde motion. This difference in particle motion (or polarity) can be used by joint analysis of vertical and horizontal inline recordings. We have developed a novel method that isolates modes by separating prograde and retrograde motions; we call this a polarity mute. Applying this polarity mute prior to traditional multichannel analysis of surface wave (MASW) analysis improves phase velocity estimation for fundamental and higher mode dispersion. This approach, in turn, should lead to improvement of S-wave velocity estimates with depth. With two simple models and a field example, we have highlighted the complexity of the Rayleigh-wave particle motions and determined improved MASW dispersion images using the polarity mute. Our results show that we can separate prograde and retrograde signals to independently process fundamental and higher mode signals, in turn allowing us to identify lower frequency dispersion when compared with single component data. These examples demonstrate that the polarity mute approach can improve estimates of S-wave velocities with depth.


2017 ◽  
Vol 12 (S 01) ◽  
pp. S1-S84
Author(s):  
B Hartmann ◽  
F Groß ◽  
P Bramlage ◽  
S Lanzinger ◽  
T Danne ◽  
...  
Keyword(s):  

2017 ◽  
pp. 89-94
Author(s):  
Ke Toan Tran ◽  
Thi Thuy Hang Nguyen

Objective: To determine pulmonary vascular resistance (PVR) by echocardiography - Doppler and to find correlation between pulmonary vascular resistance with left ventricular EF, PAPs, TAPSE, tissue S-wave of the tricuspid valve in patients with ischemic heart disease. Subjects and Methods: We studied on 82 patients with ischemic heart disease and EF<40% including 36 females, 46 males. Patients were estimated for pulmonary vascular resistance, EF, PAPs, TAPSE, tissue S-wave of the tricuspid valve by echocardiographyDoppler. Results: 64.6% of patients are increased PVR, average of PVR is 3.91 ± 1.85 Wood units and it is increasing with NYHA severity. There are negative correlations between pulmonary vascular resistance with left ventricular ejection fraction (r = - 0.545; p <0.001), TAPSE index (r= -0.590; p <0.001) and tissue S-wave of the tricuspid valve (r = -0.420; p <0.001); positive correlation with systolic pulmonary artery pressure (r = 0.361, p = 0.001), Conclusions: Increased PVR is the primary mechanism for pulmonary hypertension and right heart failure in patients with left heart disease. Determination of PVR in patients with left ventricular dysfunction by echocardiography is important in clinical practice. Key words: Echocardiography-Doppler; Pulmonary vascular resistance; ischemic heart disease


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