scholarly journals Railways’ Stability Observation by Satellite Radar Images

2018 ◽  
Author(s):  
Davod Poreh ◽  
Antonio Iodice ◽  
Daniele Riccio ◽  
Giuseppe Ruello
Keyword(s):  
Radar Images ◽  
Satellite Radar

The combination of methods for analyzing the amplitude and phase of satellite radar images for the estimation of displacements on landslide-affected slopes

2015 ◽  
Vol 70 (4) ◽  
pp. 303-311 ◽  
Author(s):  
E. A. Kiseleva ◽  
V. O. Mikhailov ◽  
E. I. Smolyaninova ◽  
E. P. Timoshkina ◽  
P. N. Dmitriev
Keyword(s):  
Radar Images ◽  
Satellite Radar ◽  
Combination Of Methods

Internal solitons on the Black Sea shelf: observation of waves of record amplitudes

2020 ◽  
Author(s):  
Andrey Serebryany ◽  
Valeriy Bondur ◽  
Viktor Zamshin
Keyword(s):  
Internal Waves ◽  
Black Sea ◽  
Satellite Images ◽  
Vertical Component ◽  
The Black Sea ◽  
Fish Food ◽  
Radar Images ◽  
Rfbr Grant ◽  
Satellite Radar ◽  
First Time

<p>When conducting work in the fall of 2015 on the Black Sea northeast shelf, we recorded internal waves, the unusualness of which attracts special attention for the following reasons. For the first time in 40 years of internal waves observations in the Black Sea, such high waves with amplitudes of 14–16 m were measured. The generation of these anomalous waves was connected with a cold atmospheric front passing over the sea. It was the first experimental evidence in the sea of such mechanism for internal waves generation. The observed internal waves had a clear seen character of nonlinear soliton-like waves.</p><p>We met the train of internal solitons during a sub-satellite survey conducted in the sea from a motor yacht equipped with ADCP “Rio Grande 600 kHz” in the waters near Cape Tolsty. The train was found at a point of the sea with a depth of 33 m and then was recorded on seven multidirectional tacks oriented normal to the coast. It moved across the shelf to the coast along the bottom thermocline, while the bottom currents accompanying it had a northwestern coastal orientation. The train included four waves of a soliton-like shape with sharpened crests and flattened troughs. Their lengths were 100-110 m, heights up to 14-16 m, vertical velocities in orbital currents reached 0.15-0.20 m/s. Another property of nonlinear waves was also expressed - the amplitude ranking of waves in the train. Traced on successive tacks for 2.5 hours, internal waves had preserved the soliton-like shape and as well the strong vertical component in their orbital currents. Despite the fact that the train was moving along the bottom thermocline, the effect of internal waves was sufficient to appear on satellite radar images of the sea surface of the study area. The performed processing of satellite images confirmed the wave parameters measured by contact methods.  An interesting fact of a long accompaniment of internal solitons by a school of fish was discovered. Fishes were concentrated in areas where internal waves carried the components of fish food supply to the surface from the bottom layers. The work was partially supported by RFBR grant 19- 05-00715.</p>

scholarly journals Satellite radar images capture a subglacial volcanic eruption in Iceland

Eos ◽  
1999 ◽  
Vol 80 (18) ◽  
pp. 205 ◽  
Author(s):  
James B. Garvin ◽  
Ahmed Mahmood ◽  
Christine Giguere
Keyword(s):  
Volcanic Eruption ◽  
Radar Images ◽  
Satellite Radar

Ground displacement over Petrinja area caused by earthquake M6.2: interdisciplinary analysis of geodesy and geology based on analysis from SAR Sentinel-1 data

2021 ◽  
Author(s):  
Olga Bjelotomić Oršulić ◽  
Tvrtko Korbar ◽  
Danko Markovinović ◽  
Matej Varga ◽  
Tomislav Bašić
Keyword(s):  
Horizontal Displacement ◽  
Ground Displacement ◽  
North West ◽  
Radar Images ◽  
New Findings ◽  
West Part ◽  
Vertical Ground ◽  
Spatio Temporal ◽  
Satellite Radar ◽  
The Impact

<p>At the very end of the year 2020, at 29th of December, hazard earthquake of M=6.2 hit near Petrinja, at NW of Croatia. Earthquake have been felt in a circumstance of a 400 kilometers, leaving in an epicenter vicinity inconceivable damage, devastated towns and obstructed lives. In order to obtain the first emergency crisis numbers over the impact of the earthquake on a ground motion, we have analyzed open satellite radar images of Copernicus Sentinel-1 along with the seismic faults. Multiple spatio-temporal Copernicus Sentinel-1 C-SAR images were used and processed for the differentiating the <em>before</em> and <em>after</em> earthquake state of the art. This presentation shows the results of the SAR conducted analysis, with the results of ground displacement in vertical up-down and horizontal east-west direction. The results show the vertical ground displacement to extent of -12 cm at southern area to +22cm at north-west part of a wide area covered by the earthquake impact regarding the epicenter. The horizontal displacement is detected in range between 30 cm towards west and 40 cm towards east is detected around the epicenter area, and +/-5cm horizontal displacement over a wider affected area indicate a spatial extent and hazardous impact the mainshock event made. The SAR results were verified by including the analysis over one station from the national positioning reference frame CROPOS. Accordingly, we obtained matching results of 5 cm easting shift and -3 cm subsidence on Sisak GNSS CROPOS station which coressponds to our SAR findings. Furthermore, geological interepretation of new findings is given based on results detecting Pokupsko and Petrinja fault.</p>

How to reveal the present-day mechanism of the 600 km long Doruneh fault in eastern Iran ?

2020 ◽  
Author(s):  
Fateme Khorrami ◽  
Andrea Walpersdorf ◽  
Zahra Mousavi ◽  
Erwan Pathier ◽  
Hamid Nankali ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Large Scale ◽  
Sand Dunes ◽  
Slip Rate ◽  
Seismic Velocities ◽  
Slip Rates ◽  
Radar Images ◽  
Eastern Iran ◽  
Spatial Coverage ◽  
Satellite Radar

<p>The enigmatic 600 km long E-W trending left-lateral Doruneh fault in eastern Iran is certified to be active by its well preserved geomorphological features all along its trace, but it is lacking recent seismic activity that could be attributed to its motion. Instead, the high seismogenic potential of the study zone is highlighted by the two M=7 earthquakes on the left-lateral E-W trending Dasht-e-Bayaz fault just south of Doruneh, in 1968 and 1979. Therefore, it remains important to understand the role of the Doruneh fault in the kinematics of the Arabia-Eurasia collision that takes place inside Iran’s political boundaries.</p><p>Many different slip-rates have been estimated for the left-lateral motion of the Doruneh fault: 2.5 mm/yr by geomorphological marker offset dating, 1 mm/yr from preliminary GNSS measurements, and 5 mm/yr from a local InSAR study.  These rather local estimates on the 600 km long fault highlight either temporal or spatial variability of the Doruneh present-day behavior. The spatial variability of the fault slip is still badly constraint as the western half of the fault is located in the Great Kavir desert. The analysis of satellite radar images was supposed to provide good constraints on the inter-seismic deformation with a full spatial coverage of the fault, especially thanks to the favorable E-W orientation of the Doruneh fault and the arid Iranian climate. However, decorrelation due to sand dunes and unexpected large tropospheric noise prohibited precise results from a first large-scale ENVISAT study, yielding an upper limit of the slip rate of 4 mm/yr. The high resolution SENTINEL-1 constellation (operational since 2014) is predicted to provide constraints on inter-seismic velocities down to 2 mm/yr from 2020 on. In complement, a dense GNSS survey has been conducted in 2012 and 2018 on a temporary network of 18 sites around a large part of the fault. This network densifies and completes the 17 permanent GNSS stations in up to 200 km distance to the fault trace situated mostly in the eastern, more populated part of the fault.</p><p>In this work, we will point out our recent GNSS, InSAR and tectonic studies on the present-day characteristics of the Doruneh fault, to better understand the mechanism of this major fault in the kinematics of the Arabia-Eurasia collision, and to contribute to a better assessment of the seismic hazard in eastern Iran.</p>

Twelve-Year Landslide Risk Assessment in Villa de Independencia, Bolivia, with Sentinel-1 and ALOS-1/2 InSAR Observations

2020 ◽  
Author(s):  
Chuang Song ◽  
Zhenhong Li ◽  
Stefano Utili ◽  
Chen Yu
Keyword(s):  
Time Series ◽  
Eigenvalue Decomposition ◽  
Landslide Risk ◽  
Time Interval ◽  
Deformation Pattern ◽  
Radar Images ◽  
Satellite Radar ◽  
North Edge ◽  
The Village ◽  
Landslide Movement

<p>Monitoring of slow landslide movement on a local scale with Interferometric Synthetic Aperture Radar (InSAR) observations can provide long-term deformation information and assist in identifying failure triggers. We combined three different tracks of satellite radar images spanning 12 years from ALOS-1 PALSAR-1, ALOS-2 PALSAR-2, and Sentinel-1 to assess the evolution of a landslide in Bolivia where the village of Independencia lies at the slope foot. For ALOS-1 PALSAR, SAR data was acquired on 15 dates during the period from 28 February 2007 to 11 March 2011 in ascending mode. For ALOS-2 PALSAR-2, eight acquisitions between 07 October 2015 and 29 November 2017 were available in ascending mode. The low temporal resolution of ALOS images makes the detection of deforming signal difficult though the L-band data captures more coherent pixels on vegetation areas than C-band. Sentinel-1 data with a minimum time interval of six days from 16 October 2014 to 08 September 2019 (144 images) is collected and processed to recover the dynamic behaviour of the landslide movement.</p><p>To explore the sensitivity of different InSAR time series analysis methods on revealing the deformation pattern of the landslide, we respectively used Persistent Scatterer Interferometry (PSI), Small Baseline Subset (SBAS) algorithm and Distributed Scatterer Interferometry (DSI) based on phase eigenvalue-decomposition to process the mentioned multiple satellite radar observations. Overlapping valid pixels from these three methods share similar temporal evolution while SBAS and DSI trace more measurement points than PSI in spatial distribution. Preliminary results show that the village central exhibits extremely slow movements (<= 10 mm/yr) with seasonal oscillation. The north edge of the village in the middle of the landslide body retains stable until 2018. Deformation time series after early 2018 perform an acceleration from about 5 mm/yr to 15 mm/yr. Such acceleration may result from artificial irrigation activities, precipitation or internal landslide reactivation, and we expect to collect more ground evidence to interpret the acceleration. To conclude, the failure risk of this landslide is relatively higher since 2018 and is more noteworthy than before.</p>

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