High‐resolution seismic velocity field estimation techniques and their application to geohazard, lithology and porosity prediction

2020 ◽  
Vol 18 (1) ◽  
pp. 61-72
Author(s):  
Vita Kalashnikova ◽  
Ivar Meisingset ◽  
Rune Øverås ◽  
Daria Krasova
Keyword(s):  
High Resolution ◽  
Velocity Field ◽  
Seismic Velocity ◽  
Estimation Techniques ◽  
Field Estimation

scholarly journals High Resolution Observations of Neutral Hydrogen in M33 - II: THE VELOCITY FIELD

1973 ◽  
Vol 163 (2) ◽  
pp. 163-182 ◽  
Author(s):  
P. J. Warner ◽  
M. C. H. Wright ◽  
J. E. Baldwin
Keyword(s):  
High Resolution ◽  
Velocity Field ◽  
Neutral Hydrogen

Large-scale, high-resolution maps of interseismic strain accumulation from Sentinel-1, and incorporation of along-track measurements

2021 ◽  
Author(s):  
Andy Hooper ◽  
Pawan Piromthong ◽  
Tim Wright ◽  
Jonathan Weiss ◽  
Milan Milan Lazecky ◽  
...  
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Velocity Field ◽  
Reference Frame ◽  
Line Of Sight ◽  
Tectonic Deformation ◽  
Low Resolution ◽  
Gnss Measurements ◽  
Along Track ◽  
East West

<p>High-resolution geodetic measurements of crustal deformation from InSAR have the potential to provide crucial constraints on a region’s tectonics, geodynamics and seismic hazard. Here, we present a high-resolution crustal velocity field for the Alpine-Himalayan Seismic Belt (AHSB) derived from Sentinel-1 InSAR and GNSS. We create time series and average velocities from ~220,000 interferograms covering an area of 15 million km<sup>2</sup>, with an average of 170 acquisitions per measurement point. We tie the velocities to a Eurasian reference frame by jointly inverting the InSAR data with GNSS data to produce a low-resolution model of 3D surface velocities. We then use the referenced InSAR velocities to invert for high-resolution east-west and sub-vertical velocity fields for the entire region. The sub-vertical velocities, which also include a small component of north-south motion, are dominated by non-tectonic deformation, such as subsidence due to water extraction. The east-west velocity field, however, reveals the tectonics of the AHSB with an unprecedented level of detail.</p><p>The approach described above only provides good constraints on horizontal displacement in the east-west direction, with the north-south component provided by low-resolution GNSS measurements. Sentinel-1 does also have the potential to provide measurements that are sensitive to north-south motion, through exploitation of the burst overlap areas produced by the TOPS acquisition mode. These along-track measurements have lower precision than line-of-sight InSAR and are more effected by ionospheric noise, but have the advantage of being almost insensitive to tropospheric noise. We present a time series approach to tease out the subtle along-track signals associated with interseismic strain. Our approach includes improvements to the mitigation of ionospheric noise and we also investigate different filtering approaches to optimize the reduction of decorrelation noise. In contrast to the relative measurements of line-of-sight InSAR, these along-track measurements are automatically provided in a global reference frame. We present results from five years of data for the West-Lut Fault in eastern Iran and the Chaman Fault in Pakistan and Afghanistan. Our results agree well with independent GNSS measurements; however, the denser coverage of the technique allows us to also detect the variation in slip rate along the faults.</p><p>Finally, we demonstrate the improvement in the resolution of horizontal strain rates when including these along-track measurements, in addition to the conventional line-of-sight InSAR measurements.</p>

scholarly journals Chromospheric Velocity Fields Diagnostics from CaII and MgII Emission Profiles

1988 ◽  
Vol 132 ◽  
pp. 283-285
Author(s):  
G. Vladilo ◽  
L. Crivellari ◽  
F. Castelli ◽  
J. E. Beckman ◽  
B. H. Foing
Keyword(s):  
High Resolution ◽  
Velocity Field ◽  
Velocity Fields

We discuss the present limits to the velocity field diagnostics in stellar chromospheres achievable with ESO CAT+CES and IUE high resolution spectra.

scholarly journals Concentration-based velocity reconstruction in convective Hele–Shaw flows

2020 ◽  
Vol 61 (9) ◽  
Author(s):  
Mobin Alipour ◽  
Marco De Paoli ◽  
Alfredo Soldati
Keyword(s):  
High Resolution ◽  
Velocity Field ◽  
Cost Effective ◽  
Velocity Fields ◽  
Reconstruction Process ◽  
Cost Effective Alternative ◽  
Laser Sources ◽  
Darcy Flows ◽  
Single Snapshot ◽  
Hele Shaw Cell

Abstract We examine the process of convective dissolution in a Hele–Shaw cell. We consider a one-sided configuration and we propose a newly developed method to reconstruct the velocity field from concentration measurements. The great advantage of this Concentration-based Velocity Reconstruction (CVR) method consists of providing both concentration and velocity fields with a single snapshot of the experiment recorded in high resolution. We benchmark our method vis–à–vis against numerical simulations in the instance of Darcy flows, and we also include dispersive effects to the reconstruction process of non-Darcy flows. The absence of laser sources and the presence of one low-speed camera make this method a safe, accurate, and cost-effective alternative to classical PIV/PTV velocimetry processes. Finally, as an example of possible application, we employ the CVR method to analyse the tip splitting phenomena. Graphic abstract

The Influence of Velocity Field Estimation on the Prediction of Far-Field Acoustics

2016 ◽  
Author(s):  
Adam Nickels ◽  
Lawrence S. Ukeiley ◽  
Robert W. Reger ◽  
Louis N. Cattafesta
Keyword(s):  
Velocity Field ◽  
Far Field ◽  
Field Estimation
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