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 Molecular Signatures of Reticulate Evolution within the Complex of European Pine Taxa

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 489
Author(s):  
Bartosz Łabiszak ◽  
Witold Wachowiak
Keyword(s):  
Gene Flow ◽  
Reticulate Evolution ◽  
Modeling Framework ◽  
Closely Related Species ◽  
Interspecific Gene Flow ◽  
Nucleotide Sequence Variation ◽  
History Of ◽  
Best Fitting ◽  
Species Integrity

Speciation mechanisms, including the role of interspecific gene flow and introgression in the emergence of new species, are the major focus of evolutionary studies. Inference of taxonomic relationship between closely related species may be challenged by past hybridization events, but at the same time, it may provide new knowledge about mechanisms responsible for the maintenance of species integrity despite interspecific gene flow. Here, using nucleotide sequence variation and utilizing a coalescent modeling framework, we tested the role of hybridization and introgression in the evolutionary history of closely related pine taxa from the Pinus mugo complex and P. sylvestris. We compared the patterns of polymorphism and divergence between taxa and found a great overlap of neutral variation within the P. mugo complex. Our phylogeny reconstruction indicated multiple instances of reticulation events in the past, suggesting an important role of interspecific gene flow in the species divergence. The best-fitting model revealed P. mugo and P. uncinata as sister species with basal P. uliginosa and asymmetric migration between all investigated species after their divergence. The magnitude of interspecies gene flow differed greatly, and it was consistently stronger from representatives of P. mugo complex to P. sylvestris than in the opposite direction. The results indicate the prominent role of reticulation evolution in those forest trees and provide a genetic framework to study species integrity maintained by selection and local adaptation.

scholarly journals Raising awareness of the cultural, architectural, and perceptive values of historic gardens and related landscapes: panoramic cones and multi-temporal data

2020 ◽  
Author(s):  
Alberta Cazzani ◽  
Carlotta Maria Zerbi ◽  
Raffaella Brumana ◽  
Anna Lobovikov-Katz
Keyword(s):  
Open Data ◽  
Historical Maps ◽  
Temporal Data ◽  
Educational Values ◽  
Policy Makers ◽  
Cadastral Maps ◽  
Raising Awareness ◽  
Multi Temporal ◽  
History Of ◽  
Historic Maps

AbstractHistoric gardens and their related landscapes are often experienced only for their social, aesthetic, and environmental resources, yet their cultural, architectural, and perceptive significance is often ignored. The paper demonstrates how historic and educational values of historic gardens and related landscapes can be revealed by combining historic maps, reading perspective cones, and also applying advanced digital and educational methods and techniques. Historical maps, especially military and cadastral maps, associated with historical iconography, can provide us with a lot of information to study historical gardens and also to define conservation and valorization plans that are related to the history of the site: geomatics tools to georeference and co-relate metric and non-metric historical maps provide growing useful outputs, that can be deployed through the use of Virtual Hubs, boosting the availability of content and the accessibility of open data for policy makers, experts, and non-expert members. Moreover, they can also support heritage education programs providing the opportunity to allow to understand the wealth of sites now simplified, in their system, with different functions and with a transformed context. The study of historic gardens involves the analysis of the landscape in its dynamism and complexity, defines tools that make users more aware of the richness of our heritage.

scholarly journals Geological monitoring networks for risk management close to large rock cliffs: the case history of Gallivaggio and Cataeggio in the italian Alps

2021 ◽  
Vol 76 (1) ◽  
pp. 85-101
Author(s):  
Luca Dei Cas ◽  
Maria Luisa Pastore ◽  
Andrea Pavan ◽  
Nicola Petrella
Keyword(s):  
Early Warning ◽  
Rock Slope ◽  
Monitoring Network ◽  
Monitoring Networks ◽  
Italian Alps ◽  
Synthetic Aperture Radar Interferometry ◽  
Reliable Monitoring ◽  
Critical Issues ◽  
History Of ◽  
Short Time

Abstract. In areas located near large rock cliffs, risk reduction by early warning monitoring systems highligts potentiality but also critical issues and limits. The paper examines two rock slope failures that occurred in a short time from each other near inhabited areas in the Italian Alps. The viscous behavior of the rock mass was reconstructed through data processing from ground-based Synthetic Aperture Radar Interferometry (InSAR), and elaboration of acceleration and speed curves. Landslides types and underlying complexity associated with rock detachment mechanisms suggest the identification of precautionary alarm thresholds for collapse forecasting. The analysis of financial outlay, both for mitigation works and for monitoring activities, highlight the adequacy and the opportunity to combine passive systems, like embankments or rockfall drapery meshes, with a reliable monitoring network for early warning.

scholarly journals Advanced radar-interpretation of InSAR time series for mapping and characterization of geological processes

2011 ◽  
Vol 11 (3) ◽  
pp. 865-881 ◽  
Author(s):  
F. Cigna ◽  
C. Del Ventisette ◽  
V. Liguori ◽  
N. Casagli
Keyword(s):  
Time Series ◽  
Field Surveys ◽  
Synthetic Aperture Radar Interferometry ◽  
Geological Processes ◽  
Multi Temporal ◽  
Under Sampling ◽  
Temporal Measures

Abstract. We present a new post-processing methodology for the analysis of InSAR (Synthetic Aperture Radar Interferometry) multi-temporal measures, based on the temporal under-sampling of displacement time series, the identification of potential changes occurring during the monitoring period and, eventually, the classification of different deformation behaviours. The potentials of this approach for the analysis of geological processes were tested on the case study of Naro (Italy), specifically selected due to its geological setting and related ground instability of unknown causes that occurred in February 2005. The time series analysis of past (ERS1/2 descending data; 1992–2000) and current (RADARSAT-1 ascending data; 2003–2007) ground movements highlighted significant displacement rates (up to 6 mm yr−1) in 2003–2007, followed by a post-event stabilization. The deformational behaviours of instable areas involved in the 2005 event were also detected, clarifying typology and kinematics of ground instability. The urban sectors affected and unaffected by the event were finally mapped, consequently re-defining and enlarging the influenced area previously detected by field observations. Through the integration of InSAR data and conventional field surveys (i.e. geological, geomorphologic and geostructural campaigns), the causes of instability were finally attributed to tectonics.

Admixture analysis of age at onset in obsessive–compulsive disorder

2005 ◽  
Vol 35 (2) ◽  
pp. 237-243 ◽  
Author(s):  
RICHARD DELORME ◽  
JEAN-LOUIS GOLMARD ◽  
NADIA CHABANE ◽  
BRUNO MILLET ◽  
MARIE-ODILE KREBS ◽  
...  
Keyword(s):  
Obsessive Compulsive Disorder ◽  
Late Onset ◽  
Age At Onset ◽  
Admixture Analysis ◽  
Obsessive Compulsive ◽  
General Anxiety Disorder ◽  
General Anxiety ◽  
Compulsive Disorder ◽  
History Of ◽  
Best Fitting

Background. Age at onset (AAO) has been useful to explore the clinical, neurobiological and genetic heterogeneity of obsessive–compulsive disorder (OCD). However, none of the various thresholds of AAO used in previous studies have been validated, and it remains an unproven notion that AAO is a marker for different subtypes of OCD. If AAO is a clinical indicator of different biological subtypes, then subgroups based on distinct AAOs should have separate normal distributions as well as different clinical characteristics.Method. Admixture analysis was used to determine the best-fitting model for the observed AAO of 161 OCD patients.Results. The observed distribution of AAO in OCD is a mixture of two Gaussian distributions with mean ages of 11·1±4·1 and 23·5±11·1 years. The first distribution, defined by early-onset OCD, had increased frequency of Tourette's syndrome and increased family history of OCD. The second distribution, defined by late-onset OCD, showed elevated prevalence of general anxiety disorder and major depressive disorder.Conclusions. These results, based on a statistically validated AAO cut-off and those of previous studies on AAO in OCD, suggest that AAO is a crucial phenotypic characteristic in understanding the genetic basis of this disorder.

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 Diversification of African Rainforest Restricted Clades: Piptostigmateae and Annickieae (Annonaceae)

Diversity ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 227 ◽  
Author(s):  
Baptiste Brée ◽  
Andrew J. Helmstetter ◽  
Kévin Bethune ◽  
Jean-Paul Ghogue ◽  
Bonaventure Sonké ◽  
...  
Keyword(s):  
East Africa ◽  
East African ◽  
African Species ◽  
Extinction Rates ◽  
West Central ◽  
History Of ◽  
Best Fitting ◽  
The One ◽  
Extinction Events ◽  
The Impact

African rainforests (ARFs) are species rich and occur in two main rainforest blocks: West/Central and East Africa. This diversity is suggested to be the result of recent diversification, high extinction rates and multiple vicariance events between west/central and East African forests. We reconstructed the diversification history of two subtribes (Annickieae and Piptostigmateae) from the ecologically dominant and diverse tropical rainforest plant family Annonaceae. Both tribes contain endemic taxa in the rainforests of West/Central and East Africa. Using a dated molecular phylogeny based on 32 nuclear markers, we estimated the timing of the origin of East African species. We then undertook several diversification analyses focusing on Piptostigmateae to infer variation in speciation and extinction rates, and test the impact of extinction events. Speciation in both tribes dated to the Pliocene and Pleistocene. In particular, Piptostigma (13 species) diversified mainly during the Pleistocene, representing one of the few examples of Pleistocene speciation in an African tree genus. Our results also provide evidence of an ARF fragmentation at the mid-Miocene linked to climatic changes across the region. Overall, our results suggest that continental-wide forest fragmentation during the Neogene (23.03–2.58 Myr), and potentially during the Pliocene, led to one or possibly two vicariance events within the ARF clade Piptostigmateae, in line with other studies. Among those tested, the best fitting diversification model was the one with an exponential speciation rate and no extinction. We did not detect any evidence of mass extinction events. This study gives weight to the idea that the ARF might not have been so negatively impacted by extinction during the Neogene, and that speciation mainly took place during the Pliocene and Pleistocene.

Multi-Temporal InSAR for transport infrastructure monitoring: Recent trends and challenges

2022 ◽  
pp. 1-50
Author(s):  
Valentina Macchiarulo ◽  
Pietro Milillo ◽  
Chris Blenkinsopp ◽  
Cormac Reale ◽  
Giorgia Giardina
Keyword(s):  
Cost Effective ◽  
Global Scale ◽  
Deformation Monitoring ◽  
Transport Infrastructure ◽  
Structural Monitoring ◽  
Inspection Planning ◽  
Infrastructure Monitoring ◽  
Synthetic Aperture Radar Interferometry ◽  
Sensing Technology ◽  
Multi Temporal

Worldwide, transport infrastructure is increasingly vulnerable to ageing-induced deterioration and climate-related hazards. Oftentimes inspection and maintenance costs far exceed available resources, and numerous assets lack any rigorous structural evaluation. Space-borne Synthetic Aperture Radar Interferometry (InSAR) is a powerful remote-sensing technology, which can provide cheaper deformation measurements for bridges and other transport infrastructure with short revisit times, while scaling from the local to the global scale. As recent studies have shown the InSAR accuracy to be comparable with traditional monitoring instruments, InSAR could offer a cost-effective tool for long-term, near-continuous deformation monitoring, with the possibility to support inspection planning and maintenance prioritisation, while maximising functionality and increasing the resilience of infrastructure networks. However, despite the high potential of InSAR for structural monitoring, some important limitations need to be considered when applying it in reality. This paper identifies and discusses the challenges of using InSAR for the purpose of structural monitoring, with a specific focus on bridges and transport networks. Examples are presented to illustrate current practical limitations of InSAR; possible solutions and promising research directions are identified. The aim of this study is to motivate future action in this area and highlight the InSAR advances needed to overcome current challenges.

An attempt to reconstruct central and eastern Iranian ophiolite puzzle

2020 ◽  
Author(s):  
Nalan Lom ◽  
Abdul Qayyum ◽  
Douwe J.J. van Hinsbergen
Keyword(s):  
Large Scale ◽  
Central Iran ◽  
Normal Faults ◽  
Deformation Pattern ◽  
Passive Margins ◽  
The North ◽  
Sanandaj Sirjan Zone ◽  
Major Fault ◽  
History Of ◽  
Ophiolitic Rock

<p>Iran is a mosaic of continental blocks that are surrounded by Palaeo-Tethyan and Neo-Tethyan oceanic relics. Remnants of the ophiolitic rock assemblages are exposed around the Central Iranian Microcontinent (CIM), discretely along the Sanandaj-Sirjan Zone and in Jaz-Murian. The Present-day “ring” distribution of the Iranian ophiolites is not straightforwardly explained by a simple subduction zone architecture. One of the key features to solve the Iranian puzzle is the CIM which is surrounded by Sabzevar ophiolites in the north (99-77 Ma), Birjand-Nehbandan ophiolites in the east (~110 Ma) and Inner Zagros ophiolites in south-southwest (~103-94 Ma). The CIM consists of three major fault bounded sub-blocks, from east to west, Lut, Tabas, and Yazd. They represent an Atlantic-type continental margin that began rifting in Permo-Triassic as a result of opening of Neotethys Ocean. Subsequent convergence in Cretaceous to Paleogene time close the ocean basins around the CIM and emplaced the ophiolites onto the passive margins. Neogene Arabia-Eurasia collision induced replacement structures e.g., strike‐slip reactivation of normal faults that were associated with major block rotations.</p><p>We aim to kinematically restore the opening and closure history of the ocean basins found as ophiolitic relics around the CIM. Key in our analysis is the Doruneh and Great Kavir faults of Central Iran that continues into northern Afghanistan as the Herat Fault. Present-day GPS velocity vector measurements and deformation pattern show a NE-SW orientated shortening in Iran. Structural analysis of the Doruneh Fault indicates slip sense inversion before ~5 Ma. This observation is consistent with the deactivation of the dextral Herat Fault. Pre-Pliocene dextral movement in excess of 500 km along the Doruneh and Great Kavir faults may kinematically accommodate a major counter-clockwise rotation (~65<span>o</span>) of the CIM since the late Jurassic that has been inferred based on previous palaeomagnetic studies. This enables the transport of the Jandaq ophiolite from Aghdarband in the north to Anarak region of Central Iran and, duplication of curved Birjand-Nehbandan ophiolites in Sistan suture. If correct, this may imply that the closure history of the Central Iranian basins is directly connected to the large-scale Cretaceous to Paleogene extrusion tectonics in western Tibet and Hindu Kush regions. This preliminary study shows restoration of the post-Mesozoic deformation is essential to reconstruct the suture zones and pre-collisional setting in Iran, Afghanistan, and Pakistan.</p>

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