scholarly journals Analysis of the deformation pattern along the subduction zone of Crete, Greece, using multi-temporal ERS and Envisat data

2015 ◽  
Author(s):  
Maria Kaskara ◽  
Aggeliki Barberopoulou ◽  
Ioannis Papoutsis ◽  
Charalampos Kontoes ◽  
Athanassios Ganas ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Deformation Pattern ◽  
Multi Temporal

scholarly journals Multi-Sensor SAR Geodetic Imaging and Modelling of Santorini Volcano Post-Unrest Response

2019 ◽  
Vol 11 (3) ◽  
pp. 259 ◽  
Author(s):  
Elena Papageorgiou ◽  
Michael Foumelis ◽  
Elisa Trasatti ◽  
Guido Ventura ◽  
Daniel Raucoules ◽  
...  
Keyword(s):  
Deformation Pattern ◽  
Volcano Deformation ◽  
Isotropic Source ◽  
Synthetic Aperture Radar Interferometry ◽  
Spatial Deformation ◽  
Deformation State ◽  
Multi Temporal ◽  
History Of ◽  
Best Fitting ◽  
Santorini Volcano

Volcanic history of Santorini over recent years records a seismo-volcanic unrest in 2011–12 with a non-eruptive behavior. The volcano deformation state following the unrest was investigated through multi-sensor Synthetic Aperture Radar Interferometry (InSAR) time series. We focused on the analysis of Copernicus Sentinel-1, Radarsat-2 and TerraSAR-X Multi-temporal SAR Interferometric (MT-InSAR) results, for the post-unrest period 2012–17. Data from multiple Sentinel-1 tracks and acquisition geometries were used to constrain the E-W and vertical components of the deformation field along with their evolution in time. The interpretation of the InSAR observations and modelling provided insights on the post-unrest deformation pattern of the volcano, allowing the further re-evaluation of the unrest event. The increase of subsidence rates on Nea Kameni, in accordance with the observed change of the spatial deformation pattern, compared to the pre-unrest period, suggests the superimposition of various deformation sources. Best-fitting inversion results indicate two deflation sources located at southwestern Nea Kameni at 1 km depth, and in the northern intra-caldera area at 2 km depth. A northern sill-like source interprets the post-unrest deflation attributed to the passive degassing of the magma intruded at 4 km during the unrest, while an isotropic source at Nea Kameni simulates a prevailing subsidence occurring since the pre-unrest period (1992–2010).

scholarly journals MULTI-TEMPORAL SAR INTERFEROMETRY FOR LANDSLIDE MONITORING

2016 ◽  
Vol XLI-B8 ◽  
pp. 55-58
Author(s):  
R. Dwivedi ◽  
A. B. Narayan ◽  
A. Tiwari ◽  
O. Dikshit ◽  
A. K. Singh
Keyword(s):  
Surface Deformation ◽  
Deformation Monitoring ◽  
Sar Interferometry ◽  
Line Of Sight ◽  
Landslide Monitoring ◽  
Deformation Pattern ◽  
Mean Velocity ◽  
Study Region ◽  
Persistent Scatterer ◽  
Multi Temporal

In the past few years, SAR Interferometry specially InSAR and D-InSAR were extensively used for deformation monitoring related applications. Due to temporal and spatial decorrelation in dense vegetated areas, effectiveness of InSAR and D-InSAR observations were always under scrutiny. Multi-temporal InSAR methods are developed in recent times to retrieve the deformation signal from pixels with different scattering characteristics. Presently, two classes of multi-temporal InSAR algorithms are available- Persistent Scatterer (PS) and Small Baseline (SB) methods. This paper discusses the Stanford Method for Persistent Scatterer (StaMPS) based PS-InSAR and the Small Baselines Subset (SBAS) techniques to estimate the surface deformation in Tehri dam reservoir region in Uttarkhand, India. Both PS-InSAR and SBAS approaches used sixteen ENVISAT ASAR C-Band images for generating single master and multiple master interferograms stack respectively and their StaMPS processing resulted in time series 1D-Line of Sight (LOS) mean velocity maps which are indicative of deformation in terms of movement towards and away from the satellites. From 1D LOS velocity maps, localization of landslide is evident along the reservoir rim area which was also investigated in the previous studies. Both PS-InSAR and SBAS effectively extract measurement pixels in the study region, and the general results provided by both approaches show a similar deformation pattern along the Tehri reservoir region. Further, we conclude that StaMPS based PS-InSAR method performs better in terms of extracting more number of measurement pixels and in the estimation of mean Line of Sight (LOS) velocity as compared to SBAS method. It is also proposed to take up a few major landslides area in Uttarakhand for slope stability assessment.

scholarly journals MULTI-TEMPORAL SAR INTERFEROMETRY FOR LANDSLIDE MONITORING

2016 ◽  
Vol XLI-B8 ◽  
pp. 55-58 ◽  
Author(s):  
R. Dwivedi ◽  
A. B. Narayan ◽  
A. Tiwari ◽  
O. Dikshit ◽  
A. K. Singh
Keyword(s):  
Surface Deformation ◽  
Deformation Monitoring ◽  
Sar Interferometry ◽  
Line Of Sight ◽  
Landslide Monitoring ◽  
Deformation Pattern ◽  
Mean Velocity ◽  
Study Region ◽  
Persistent Scatterer ◽  
Multi Temporal

In the past few years, SAR Interferometry specially InSAR and D-InSAR were extensively used for deformation monitoring related applications. Due to temporal and spatial decorrelation in dense vegetated areas, effectiveness of InSAR and D-InSAR observations were always under scrutiny. Multi-temporal InSAR methods are developed in recent times to retrieve the deformation signal from pixels with different scattering characteristics. Presently, two classes of multi-temporal InSAR algorithms are available- Persistent Scatterer (PS) and Small Baseline (SB) methods. This paper discusses the Stanford Method for Persistent Scatterer (StaMPS) based PS-InSAR and the Small Baselines Subset (SBAS) techniques to estimate the surface deformation in Tehri dam reservoir region in Uttarkhand, India. Both PS-InSAR and SBAS approaches used sixteen ENVISAT ASAR C-Band images for generating single master and multiple master interferograms stack respectively and their StaMPS processing resulted in time series 1D-Line of Sight (LOS) mean velocity maps which are indicative of deformation in terms of movement towards and away from the satellites. From 1D LOS velocity maps, localization of landslide is evident along the reservoir rim area which was also investigated in the previous studies. Both PS-InSAR and SBAS effectively extract measurement pixels in the study region, and the general results provided by both approaches show a similar deformation pattern along the Tehri reservoir region. Further, we conclude that StaMPS based PS-InSAR method performs better in terms of extracting more number of measurement pixels and in the estimation of mean Line of Sight (LOS) velocity as compared to SBAS method. It is also proposed to take up a few major landslides area in Uttarakhand for slope stability assessment.

scholarly journals Discrete element modeling of a subduction zone with a seafloor irregularity and its impact on the seismic cycle

2020 ◽  
Author(s):  
Liqing Jiao ◽  
Chung-Han Chan ◽  
Luc Scholtès ◽  
Aurélia Hubert-Ferrari ◽  
Frédéric-Victor Donzé ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Discrete Element ◽  
Deformation Pattern ◽  
Discrete Element Modeling ◽  
Coseismic Slip ◽  
Rupture Length ◽  
Major Fault ◽  
Large Earthquakes ◽  
Earthquake Cycles ◽  
Subducting Slab

Abstract. Seafloor irregularities influence rupture behavior along the subducting slab and in the overriding plate, thus affecting earthquake cycles. Whether seafloor irregularities increase the likelihood of large earthquakes in a subduction zone remains contested, partially due to focus put either on fault development or on rupture pattern. Here, we simulate a subducting slab with a seafloor irregularity and the resulting deformation pattern of the overriding plate using the discrete element method. Our simulations illustrate the rupture along three major fault systems: megathrust, splay and backthrust faults. Our results show different rupture dimensions of earthquake events varying from tens to ca. 140 km. Our results suggest that the recurrence interval of megathrust events with rupture length of ca. 100 km is ca. 140 years, which is overall comparable to the paleoseismic records at the Mentawai area of the Sumatran zone. We further propose the coseismic slip amounts decrease and interseismic slip amounts increase from the surface downwards gradually. We conclude that the presence of seafloor irregularities significantly affects rupture events along the slab as well as fault patterns in the overriding plate.

Active upper crust deformation pattern along the southern edge of the Tyrrhenian subduction zone (NE Sicily): Insights from a multidisciplinary approach

2015 ◽  
Vol 657 ◽  
pp. 205-218 ◽  
Author(s):  
Mimmo Palano ◽  
Domenico Schiavone ◽  
Mariano Loddo ◽  
Marco Neri ◽  
Debora Presti ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Multidisciplinary Approach ◽  
Deformation Pattern ◽  
Upper Crust ◽  
Ne Sicily ◽  
Crust Deformation

scholarly journals Multi-Temporal Investigation of the Boulder Clay Glacier and Northern Foothills (Victoria Land, Antarctica) by Integrated Surveying Techniques

2019 ◽  
Vol 11 (12) ◽  
pp. 1501 ◽  
Author(s):  
Stefano Urbini ◽  
Gianluca Bianchi-Fasani ◽  
Paolo Mazzanti ◽  
Alfredo Rocca ◽  
Luca Vittuari ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Sar Interferometry ◽  
Stereo Image ◽  
Deformation Pattern ◽  
Victoria Land ◽  
Multi Temporal ◽  
Geophysical Investigations ◽  
Boulder Clay ◽  
Ground Penetrating

The paper aims to detect the main changes that occurred in the area surrounding the Mario Zucchelli Station (MZS) through analysis of multi-temporal remote sensing integrated by geophysical measurements. Specific attention was directed at realizing an integrated geomorphological study of the Boulder Clay Glacier, a partially debris-covered glacier belonging to the Northern Foothills (Victoria Land, Antarctica). This area was recently chosen as the location for the construction of a new semi-permanent gravel runway for MZS logistical airfreight operations. Photogrammetric analysis was performed by comparing three historical aerial photogrammetric surveys (carried out in 1956, 1985, and 1993) and Very High Resolution (VHR) GeoEye-1 satellite stereo-image coverage acquired in 2012. The comparison of geo-referenced orthophoto-mosaics allowed the main changes occurring in some particular areas along the coast nearby MZS to be established. Concerning the study of the Boulder Clay Glacier, it has to be considered that glaciers and moraines are not steady-state systems by definition. Several remote sensing and geophysical investigations were carried out with the main aim of determining the general assessment of this glacier: Ground Penetrating Radar (GPR); Geodetic Global Positioning System (GPS) network; multi-temporal satellite Synthetic Aperture Radar (SAR) interferometry. The analysis of Boulder Clay Glacier moraine pointed out a deformation of less than 74 mm y−1 in a time span of 56 years, value that agrees with velocity and deformation data observed by GPS and InSAR methods. The presence of unexpected brine ponds at the ice/bedrock interface and the deformation pattern observed in the central part of the moraine has to be monitored and studied, especially under the long-term maintenance of the future runway.

The Relationship Between Leader–Member Exchange and Employees’ Proactive Behaviors

2019 ◽  
Vol 18 (2) ◽  
pp. 106-111
Author(s):  
Fong-Yi Lai ◽  
Szu-Chi Lu ◽  
Cheng-Chen Lin ◽  
Yu-Chin Lee
Keyword(s):  
Hierarchical Linear Modeling ◽  
Future Research ◽  
Leader Member Exchange ◽  
Voice Behavior ◽  
Linear Modeling ◽  
Team Members ◽  
Member Exchange ◽  
Multi Temporal ◽  
The Relationship ◽  
Practical Implications

Abstract. The present study proposed that, unlike prior leader–member exchange (LMX) research which often implicitly assumed that each leader develops equal-quality relationships with their supervisors (leader’s LMX; LLX), every leader develops different relationships with their supervisors and, in turn, receive different amounts of resources. Moreover, these differentiated relationships with superiors will influence how leader–member relationship quality affects team members’ voice and creativity. We adopted a multi-temporal (three wave) and multi-source (leaders and employees) research design. Hypotheses were tested on a sample of 227 bank employees working in 52 departments. Results of the hierarchical linear modeling (HLM) analysis showed that LLX moderates the relationship between LMX and team members’ voice behavior and creative performance. Strengths, limitations, practical implications, and directions for future research are discussed.

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