Active surface deformation in the south-central Andes revealed by multiple-sensor InSAR, GNSS and field observations

2020 ◽  
Author(s):  
Bodo Bookhagen ◽  
Manfred R. Strecker ◽  
Jonathan R. Weiss ◽  
Ricardo N. Alonso
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Central Andes ◽  
Tectonic Activity ◽  
Spatiotemporal Pattern ◽  
Tectonic Deformation ◽  
Field Observations ◽  
Cosmogenic Nuclide ◽  
Decadal Scale ◽  
Gnss Data

<p>With an average elevation of about 3.7 km the semi-arid to arid Central Andean Plateau (Altiplano-Puna) constitutes the world’s second largest orogenic plateau. The internally drained region is characterized by compressional basin-and-range topography. Many of the basins in the Argentine sector of the plateau (Puna) are presently evaporitic salt pans, but during the Pleistocene the basins have repeatedly experienced high lake-level phases during pluvial periods. Due to protracted sedimentary infilling and sustained internal drainage conditions the basins have thick sedimentary sequences that have partially coalesced. The basins are bordered by reverse-fault bounded ranges, reaching 5 to 6 km elevation, but the history and extent of tectonic deformation in this region is not very well known. Global Navigation Satellite System<span> (</span>GNSS) data have been used to estimate decadal-scale tectonic shortening rates but the spatiotemporal pattern of surface deformation is complex and includes the compounding effects of subduction zone megathrust earthquake transients.</p><p>Here, we use a combination of field observations, cosmogenic nuclide dating of deformed alluvial-fan surfaces, Interferometric Synthetic Aperture Radar (InSAR), and GNSS data time series to quantify Quaternary to decadal-scale tectonic deformation. The arid mountain ranges provide ideal conditions to observe deformation from multiple sensors, including TerraSAR-X, Sentinel-1, ALOS2, and ENVISAT. Furthermore, we rely on 12 m TanDEM-X topographic data to characterize 10<sup>3</sup>-10<sup>6</sup> yr surface deformation using cosmogenic nuclide exposure dating and digital elevation model analysis.</p><p> The Puna has been previously characterized as a region with little tectonic activity including very low levels of seismicity despite evidence for strike-slip and extensional faulting accompanied by mafic volcanism. The eastern plateau margins in particular record this type of kinematic regime, while the adjacent foreland is characterized by a higher level of seismicity and ongoing contraction. Here, we present evidence of ongoing contraction during the past two decades compatible with tectono-geomorphic phenomena that support the notion of tectonic shortening in the central Puna Plateau. For example, tilted shorelines associated with former lake-highstands along the flanks of an anticline and Neogene-Pleistocene growth strata associated with this structure indicate that shortening in this region has been sustained since the Neogene. InSAR and GNSS time series analysis permit the identification and characterization of previously unrecognized tectonic activity in adjacent sectors of the intermontane basins, thus helping to improve our understanding of crustal dynamics in the Central Andes.</p>

Tectonic Deformation and Surface Processes of the Tibetan Plateau Constrained by Time Series Analysis of Sentinel-1 InSAR Data

2020 ◽  
Author(s):  
Robert Zinke ◽  
Gilles Peltzer ◽  
Eric Fielding ◽  
Simran Sangha ◽  
David Bekaert ◽  
...  
Keyword(s):  
Time Series ◽  
Tibetan Plateau ◽  
Surface Deformation ◽  
Active Faults ◽  
High Rate ◽  
Surface Processes ◽  
Tectonic Deformation ◽  
The Tibetan Plateau ◽  
Data Set ◽  
Temporal Sampling

<p>We quantify deformation patterns resulting from tectonic motions and surface processes across the central Tibetan Plateau (29–45ºN, 83–92ºE) since late 2014 using ascending and descending passes of the Sentinel-1A and -1B radar satellites. The broad spatial extent of these data (> 10<sup>6</sup> km<sup>2</sup>), fine spatial resolution (originally 90 m pixels, resampled to 270 m pixels), and high rate of temporal sampling (12–24-day orbit repeat time) offer unprecedented resolution of surface deformation in space and time. To process such an extensive data set – including more than 100 dates and 300 interferograms per track thus far – we leverage the Advanced Rapid Imaging and Analysis (ARIA) standardized interferometric synthetic aperture radar (InSAR) products and toolbox. We construct time series of surface deformation constrained from our Sentinel-1 interferograms using the small baseline subset approach implemented by the Miami InSAR time series software in Python (MintPy). Our preliminary results from three Sentinel-1 orbits (two descending and one ascending; each comprising 10 frames along track) allow us to quantify deformation in the satellite lines of sight. Combinations of ascending and descending track measurements are used to approximate east-west and vertical ground velocities. The resulting velocity fields will provide a more complete and accurate picture of interseismic strain accumulation rates across active faults in the region such as the Altyn Tagh and Kunlun faults, and allow us to study surface processes such as permafrost active layer dynamics and isostatic adjustment due to lake level changes in unparalleled scope and detail.</p>

Impact of solutions on the identification of tectonic transients: A case study using the last decade of GNSS data in South America

2021 ◽  
Author(s):  
Jonathan Bedford ◽  
Susanne Glaser ◽  
Benjamin Männel
Keyword(s):  
Time Series ◽  
South America ◽  
Reference Frame ◽  
Plate Tectonics ◽  
Tectonic Activity ◽  
Plate Boundaries ◽  
Nazca Plate ◽  
Processing Strategies ◽  
Gnss Data ◽  
Gnss Processing

<p>GNSS derived displacement time series are used to track plate tectonics and the associated motions across major plate boundaries. With a growing number of continuous GNSS observations, it is becoming increasingly apparent that plate trajectories rarely conform to standard trajectory models. The deviations from these expected trajectories can be considered as transient motions, some being tectonically related, and others being related to geophysical fluid loading, local site effects, and artifacts of the GNSS processing. As we increasingly inspect the transient motions of GNSS displacement time series, we have to take care that the GNSS processing choices, such as the reference frame<!-- The reference frame is already the realization of the system. Just a terminology fineness. -->, are not introducing non-tectonically related artifacts into the eventual isolated tectonic signals.</p><p>Here we explore the effects that different solutions <!-- Take up the abstract title. -->and processing strategies have on our eventual daily GNSS displacement time series - the aim being to explain how artifacts arise and to determine which strategies best mitigate these artifacts. We compare displacement time series made from both Precise Point Positioning and network (double-differenced) solutions that are provided in the latest official reference frame solution ITRF2014, and in JTRF2014 based on Kalman filtering.</p><p>In our analyses, we use approximately one hundred GNSS stations from South America, with a focus being to identify transient tectonic activity related to the subduction of the Nazca plate under Chile over the past decade.</p><p> </p>

Analysis of the hydrological and tectonic deformation in the eastern part of the Tibetan plateau, from FLATSIM automated time series analysis of Sentinel-1 InSAR

2021 ◽  
Author(s):  
Laëtitia Lemrabet ◽  
Marie-Pierre Doin ◽  
Cécile Lasserre ◽  
Anne Replumaz ◽  
Marianne Métois ◽  
...  
Keyword(s):  
Time Series ◽  
Tibetan Plateau ◽  
Time Series Analysis ◽  
Surface Deformation ◽  
Tectonic Deformation ◽  
The Tibetan Plateau ◽  
Continental Scale ◽  
Series Analysis ◽  
Fault Systems ◽  
Seasonal Signal

<p>The global and systematic coverage of Sentinel-1 radar images allows characterizing, by radar interferometry (InSAR), surface deformation on a continental scale.</p><p>Our study focuses on the eastern part of the Tibetan plateau, where a combination of major strike-slip and thrust fault systems accommodates part of the deformation related to the collision between the Indian and Eurasian plates.</p><p>We use an automated Sentinel-1 InSAR processing chain based on the NSBAS approach (Doin et al., 2011, Grandin, 2015) to measure the interseismic deformation across these fault systems. Processing is made on the CNES high-performance computer center in Toulouse in the FLATSIM project framework (ForM@Ter LArge-scale multi-Temporal Sentinel-1 Interferometric Measurement, Durand et al., 2019). We perform a time series analysis of the 2014-2020 Sentinel-1 InSAR data set, for 1200 km-long tracks (acquired along 7 ascending and 7 descending orbits), covering a 1 700 000 km<sup>2</sup> area, with a 160 m spatial resolution. From about 130 acquisitions per track, we perform about 600 interferograms, with short, three months, and one-year temporal baselines. After inversion, we obtain time series of line-of-sight (LOS) delay maps, including residual atmospheric delay and network misclosure measurements. The time series are fitted by a seasonal signal plus a velocity trend. The velocity field on overlap areas agrees within less than 1~mm/yr.</p><p>Finally, we decompose the LOS velocity maps into a vertical and a horizontal contribution.</p><p>InSAR velocity maps highlight surface deformation patterns mostly localized on known major faults, short-wavelength patterns attributed to slope instabilities phenomena, and hydrological signals.</p><p>The seasonal signal combines residual atmospheric phase delays and widespread hydrological phenomena in sedimentary basins, which we interpret in parallel with the regional geological map.  Masking areas affected by dominant gravitational slope or hydrological deformation allows to better focus on tectonic deformation.</p><p>We finally discuss slip partitioning on the various fault systems from the velocity maps and 2D profiles’ analysis.</p>

Crustal folds alter local stress fields as demonstrated by magma sheet – fold interactions in the Central Andes

2021 ◽  
Author(s):  
Matías Clunes ◽  
John Browning ◽  
José Cembrano ◽  
Carlos Marquardt ◽  
Agust Gudmundsson
Keyword(s):  
Surface Deformation ◽  
Local Stress ◽  
Volcanic Eruptions ◽  
Central Andes ◽  
Stress Fields ◽  
Field Observations ◽  
Magma Chambers ◽  
The Core ◽  
Principal Compressive Stress ◽  
The Andes

<p>For magma chambers to form or volcanic eruptions to occur magma must propagate through the crust as dikes, inclined sheets and sills. The vast majority of models that investigate magma paths assume the crust to be either homogeneous or horizontally layered, often composed of rocks of contrasting mechanical properties. In subduction regions that have experienced orogenesis, like the Andes, the crust has been deformed over several million years, resulting in rock layers that are commonly folded and steeply dipping. The assumption of homogeneous properties or horizontal layering then does not capture all of the potential magma path crustal interactions. Here we tackle this problem by determining the effect of a crust made of steeply inclined layers in which sills and inclined sheets are emplaced. We combine field observations from a sill emplaced in the core of an anticlinal fold at El Juncal in the Chilean Central Andes, such as lithologies, sill and fold limbs attitude, sill length and layers and sill thickness, with a suite of finite element method models to explore the mechanical interactions between inclined layers and magma paths. Our results demonstrate that the properties of the host rock layers as well as the contacts between the layers and the crustal geometry all play an important role on magma propagation and emplacement at shallow levels. Sill propagation and emplacement through heterogeneous and anisotropic crustal segments changes the crustal stress field promoting sill arrest, deflection or propagation. Specifically, sills are more likely to be deflected when encountering shallow dipping layers rather than steeply dipping layers of a fold. Mechanically weak contacts encourage sill deflection due to the related rotation of the maximum principal compressive stress and this effect is attenuated when the fold layers are more steeply dipping. This processes may change the amount and style of surface deformation recorded, with significant implications for monitoring of active volcanoes.</p>

scholarly journals Constructing Adaptive Deformation Models for Estimating DEM Error in SBAS-InSAR Based on Hypothesis Testing

2021 ◽  
Vol 13 (10) ◽  
pp. 2006
Author(s):  
Jun Hu ◽  
Qiaoqiao Ge ◽  
Jihong Liu ◽  
Wenyan Yang ◽  
Zhigui Du ◽  
...  
Keyword(s):  
Time Series ◽  
Hypothesis Testing ◽  
Surface Deformation ◽  
A Priori ◽  
Least Square ◽  
Deformation Model ◽  
Phase Time ◽  
Testing Theory ◽  
Sbas Insar ◽  
Deformation Models

The Interferometric Synthetic Aperture Radar (InSAR) technique has been widely used to obtain the ground surface deformation of geohazards (e.g., mining subsidence and landslides). As one of the inherent errors in the interferometric phase, the digital elevation model (DEM) error is usually estimated with the help of an a priori deformation model. However, it is difficult to determine an a priori deformation model that can fit the deformation time series well, leading to possible bias in the estimation of DEM error and the deformation time series. In this paper, we propose a method that can construct an adaptive deformation model, based on a set of predefined functions and the hypothesis testing theory in the framework of the small baseline subset InSAR (SBAS-InSAR) method. Since it is difficult to fit the deformation time series over a long time span by using only one function, the phase time series is first divided into several groups with overlapping regions. In each group, the hypothesis testing theory is employed to adaptively select the optimal deformation model from the predefined functions. The parameters of adaptive deformation models and the DEM error can be modeled with the phase time series and solved by a least square method. Simulations and real data experiments in the Pingchuan mining area, Gaunsu Province, China, demonstrate that, compared to the state-of-the-art deformation modeling strategy (e.g., the linear deformation model and the function group deformation model), the proposed method can significantly improve the accuracy of DEM error estimation and can benefit the estimation of deformation time series.

scholarly journals Locally and Remotely Forced Subtropical AMOC Variability: A Matter of Time Scales

2020 ◽  
Vol 33 (12) ◽  
pp. 5155-5172
Author(s):  
Quentin Jamet ◽  
William K. Dewar ◽  
Nicolas Wienders ◽  
Bruno Deremble ◽  
Sally Close ◽  
...  
Keyword(s):  
Time Series ◽  
Time Scales ◽  
North Atlantic ◽  
Time Scale ◽  
Low Frequency ◽  
Meridional Overturning Circulation ◽  
Open Boundary ◽  
Overturning Circulation ◽  
Decadal Scale ◽  
Meridional Overturning

AbstractMechanisms driving the North Atlantic meridional overturning circulation (AMOC) variability at low frequency are of central interest for accurate climate predictions. Although the subpolar gyre region has been identified as a preferred place for generating climate time-scale signals, their southward propagation remains under consideration, complicating the interpretation of the observed time series provided by the Rapid Climate Change–Meridional Overturning Circulation and Heatflux Array–Western Boundary Time Series (RAPID–MOCHA–WBTS) program. In this study, we aim at disentangling the respective contribution of the local atmospheric forcing from signals of remote origin for the subtropical low-frequency AMOC variability. We analyze for this a set of four ensembles of a regional (20°S–55°N), eddy-resolving (1/12°) North Atlantic oceanic configuration, where surface forcing and open boundary conditions are alternatively permuted from fully varying (realistic) to yearly repeating signals. Their analysis reveals the predominance of local, atmospherically forced signal at interannual time scales (2–10 years), whereas signals imposed by the boundaries are responsible for the decadal (10–30 years) part of the spectrum. Due to this marked time-scale separation, we show that, although the intergyre region exhibits peculiarities, most of the subtropical AMOC variability can be understood as a linear superposition of these two signals. Finally, we find that the decadal-scale, boundary-forced AMOC variability has both northern and southern origins, although the former dominates over the latter, including at the site of the RAPID array (26.5°N).

scholarly journals GPS measurements on pre-, co- and post-seismic surface deformation at first multi-parametric geophysical observatory, Ghuttu in Garhwal Himalaya, India

2020 ◽  
Vol 10 (1) ◽  
pp. 136-144
Author(s):  
P.K. Gautam ◽  
S. Rajesh ◽  
N. Kumar ◽  
C.P. Dabral
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Translational Motion ◽  
Anomalous Behavior ◽  
Deformation Pattern ◽  
Local Earthquakes ◽  
Position Time Series ◽  
Continuous Gps ◽  
Gps Time Series ◽  
Gps Station

Abstract We investigate the surface deformation pattern of GPS station at MPGO Ghuttu (GHUT) to find out the cause of anomalous behavior in the continuous GPS time series. Seven years (2007-2013) of GPS data has been analyzed using GAMIT/GLOBK software and generated the daily position time series. The horizontal translational motion at GHUT is 43.7 ± 1 mm/yr at an angle of 41°± 3° towards NE, while for the IGS station at LHAZ, the motion is 49.4 ±1 mm/yr at 18 ± 2.5° towards NEE. The estimated velocity at GHUT station with respect to IISC is 12 ± 1 mm/yr towards SW. Besides, we have also examined anomalous changes in the time series of GHUT before, after and during the occurrences of local earthquakes by considering the empirical strain radius; such that, a possible relationship between the strain radius and the occurrences of earthquakes have been explored. We considered seven local earthquakes on the basis of Dobrovolsky strain radius condition having magnitude from 4.5 to 5.7, which occurred from 2007 to 2011. Results show irrespective of the station strain radius, pre-seismic surface deformational anomalies are observed roughly 70 to 80 days before the occurrence of a Moderate or higher magnitude events. This has been observed for the cases of those events originated from the Uttarakashi and the Chamoli seismic zones in the Garhwal and Kumaun Himalaya. Occurrences of short (< 100 days) and long (two years) inter-seismic events in the Garhwal region plausibly regulating and diffusing the regional strain accumulation.

scholarly journals Three-dimensional deformation time series of glacier motion from multiple-aperture DInSAR observation

2019 ◽  
Vol 93 (12) ◽  
pp. 2651-2660 ◽  
Author(s):  
Sergey Samsonov
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Ground Deformation ◽  
Three Dimensional ◽  
Data Sets ◽  
Ice Flow ◽  
The North ◽  
Glacier Ice ◽  
Deformation Component ◽  
3D Deformation

AbstractThe previously presented Multidimensional Small Baseline Subset (MSBAS-2D) technique computes two-dimensional (2D), east and vertical, ground deformation time series from two or more ascending and descending Differential Interferometric Synthetic Aperture Radar (DInSAR) data sets by assuming that the contribution of the north deformation component is negligible. DInSAR data sets can be acquired with different temporal and spatial resolutions, viewing geometries and wavelengths. The MSBAS-2D technique has previously been used for mapping deformation due to mining, urban development, carbon sequestration, permafrost aggradation and pingo growth, and volcanic activities. In the case of glacier ice flow, the north deformation component is often too large to be negligible. Historically, the surface-parallel flow (SPF) constraint was used to compute the static three-dimensional (3D) velocity field at various glaciers. A novel MSBAS-3D technique has been developed for computing 3D deformation time series where the SPF constraint is utilized. This technique is used for mapping 3D deformation at the Barnes Ice Cap, Baffin Island, Nunavut, Canada, during January–March 2015, and the MSBAS-2D and MSBAS-3D solutions are compared. The MSBAS-3D technique can be used for studying glacier ice flow at other glaciers and other surface deformation processes with large north deformation component, such as landslides. The software implementation of MSBAS-3D technique can be downloaded from http://insar.ca/.

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