ON THE INTERFEROMETRIC AND POLARIMETRIC CAPABILITIES OF THE ARGENTINIAN L-BAND SARAT SYSTEM

Abstract. In this paper, some results obtained through the processing of data acquired from the Argentinian L-band SARAT system are presented. SARAT is an airborne system that was developed as a first conceptual step toward the design of the Argentinian L-Band satellite mission SAOCOM-1. In particular, some studies relevant to the data focusing, and also regarding the interferometric and polarimetric capabilities of the SARAT system are hereby shown. The considered dataset, relevant to an area located in the Cordoba province, Argentina, has been provided by the National Commission of Space Activities of Argentina (CONAE). This work has been developed in the framework of a collaboration between the Italian Space Agency (ASI) and CONAE

Morphometry of subaerial shield volcanoes and glaciovolcanoes from Reykjanes Peninsula, Iceland: Effects of eruption environment

We present a morphometric study of 33 basaltic volcanic edifices from the Reykjanes Peninsula, Iceland, using a 20 m resolution digital elevation model (DEM). Slope values distinguish subaerial from intraglacial eruption environments, with glaciovolcanic edifices having average slope values that are > 5° higher than subaerial shields. The 26 analyzed glaciovolcanic edifices are separated into 3 groups based on size, and are also categorized following the new classification scheme of tuyas by Russell et al. (2014), into 15 tindars, 1 conical tuya, 3 flat-topped tuyas and 7 complex tuyas. The glaciovolcanic edifices show a continuum of landforms ranging from small elongated tindars to large equidimensional flat-topped tuyas. The smaller edifices ( 0.1 km3) are flat-topped tuyas. The mid-sized edifices (0.01–0.1 km3) show a wide variety of shapes and classify either as tindars or as complex tuyas, with only one edifice classifying as a conical tuya. Edifice elongation tends to decrease with volume, suggesting that small edifices are primarily fissure controlled, whereas larger edifices are mainly controlled by a central vent. The mid-sized complex tuyas are transitional edifices, suggesting that some intraglacial eruptions start as fissure eruptions that subsequently concentrate into one or more central vents, whereas the mid-sized tindars suggest a sustained fissure eruption. There is a tectonic control on the orientation of the edifices evidenced by a strong correlation between edifice elongation azimuth and mapped faults and fractures. Most edifice elongations cluster between 020° and 080°, coinciding with the strike of normal faults within and at the boundary of regional volcanic systems, but some edifices have elongations that correlate with N–S striking book-shelf faults. This implies that intraglacial eruptions are controlled by pre-existing pathways in the crust, as has been previously observed for subaerial fissure eruptions. In terms of classification, quantification of the limits between the four tuya types proposed by Russell et al. (2014) is difficult because of the transitional nature shown by several edifices. A threshold of 1.8 in ellipticity index (E.I.) values can be used to distinguish tindars from the other three types. Flat-topped tuyas are distinguished by their greater overall size, their large and relatively flat summit regions, reflected in bimodal slope distributions, and their low E.I. and low to intermediate irregularity index (I.I.) values. The only analyzed conical tuya has very low E.I. and I.I. values, very small summit regions and very steep flank slopes. The complex tuyas have variable morphometries, but are in general characterized by high I.I. values and very irregular slope distributions. No correlation is observed between edifice-scale morphology and lithology (e.g. pillow dominated or hyaloclastite dominated).Fil: Pedersen, G. B. M.. University of Iceland. Institute of Earth Sciences. Nordic Volcanological Center; IslandiaFil: Grosse, Pablo. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; Argentin

Atmospheric corrections in interferometric synthetic aperture radar surface deformation – a case study of the city of Mendoza, Argentina

Differential interferometry is a remote sensing technique that allows studying crustal deformation produced by several phenomena like earthquakes, landslides, land subsidence and volcanic eruptions. Advanced techniques, like small baseline subsets (SBAS), exploit series of images acquired by synthetic aperture radar (SAR) sensors during a given time span. <br><br> Phase propagation delay in the atmosphere is the main systematic error of interferometric SAR measurements. It affects differently images acquired at different days or even at different hours of the same day. So, datasets acquired during the same time span from different sensors (or sensor configuration) often give diverging results. Here we processed two datasets acquired from June 2010 to December 2011 by COSMO-SkyMed satellites. One of them is HH-polarized, and the other one is VV-polarized and acquired on different days. <br><br> As expected, time series computed from these datasets show differences. We attributed them to non-compensated atmospheric artifacts and tried to correct them by using ERA-Interim global atmospheric model (GAM) data. With this method, we were able to correct less than 50% of the scenes, considering an area where no phase unwrapping errors were detected. We conclude that GAM-based corrections are not enough for explaining differences in computed time series, at least in the processed area of interest. We remark that no direct meteorological data for the GAM-based corrections were employed. Further research is needed in order to understand under what conditions this kind of data can be used

On the Interferometric and Polarimetric Capabilities of the Argentinian L-Band Sarat System

In this paper, some results obtained through the processing of data acquired from the Argentinian L-band SARAT system are presented. SARAT is an airborne system that was developed as a first conceptual step toward the design of the Argentinian L- Band satellite mission SAOCOM-1. In particular, some studies relevant to the data focusing, and also regarding the interferometric and polarimetric capabilities of the SARAT system are hereby shown. The considered dataset, relevant to an area located in the Cordoba province, Argentina, has been provided by the National Commission of Space Activities of Argentina (CONAE). This work has been developed in the framework of a collaboration between the Italian Space Agency (ASI) and CONAE

Surface deformation of Long Valley caldera and Mono Basin, California investigated with the SBAS-InSAR approach

We investigate the surface deformation of the eastern California area that includes Long Valley caldera and Mono Basin. We apply the SAR Interferometry (InSAR) algorithm referred to as Small BAseline Subset (SBAS) approach that allows us to generate mean deformation velocity maps and displacement time series for the investigated area. The results presented in this work represent an advancement of previous InSAR studies of the area that are mostly focused on the deformation affecting the caldera. In particular, the proposed analysis is based on 21 SAR data acquired by the ERS-1/2 sensors during the 1992–2000 time interval, and demonstrates the capability of the SBAS procedure to identify and analyze displacement patterns at different spatial scales for the overall area spanning approximately 5000 km2. Two previously unreported localized deformation effects have been detected at Paoha Island, located within the Mono Lake, and in the McGee Creek area within the Sierra Nevada mountains, a zone to the south of the Long Valley caldera. In addition a spatially extended uplift effect, which strongly affects the caldera, has been identified and analyzed in detail. The InSAR results clearly show that the displacement phenomena affecting the Long Valley caldera have a maximum in correspondence of the resurgent dome and are characterized by the sequence of three different effects: a 1992–1997 uplift background, a 1997–1998 unrest phenomenon and a 1998–2000 subsidence phase. Moreover, the analysis of the retrieved displacement time series allows us to map the extent of the zone with a temporal deformation behavior highly correlated with the detected three-phases deformation pattern: background uplift-unrest-subsidence. We show that the mapped area clearly extends outside the northern part of the caldera slopes; accordingly, we suggest that future inversion models take this new evidence into account. The final discussion is dedicated to a comparison between the retrieved InSAR measurements and a set of GPS and leveling data, confirming the validity of the results achieved through the SBASInSAR analysis.Published277–2891.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive3.2. Tettonica attiva4.3. TTC - Scenari di pericolosità vulcanicaJCR Journalreserve

Surface deformation of Long Valley caldera and Mono Basin, California investigated with the SBAS-InSAR approach

We investigate the surface deformation of the eastern California area that includes Long Valley caldera and Mono Basin. We apply the SAR Interferometry (InSAR) algorithm referred to as Small BAseline Subset (SBAS) approach that allows us to generate mean deformation velocity maps and displacement time series for the investigated area. The results presented in this work represent an advancement of previous InSAR studies of the area that are mostly focused on the deformation affecting the caldera. In particular, the proposed analysis is based on 21 SAR data acquired by the ERS-1/2 sensors during the 1992–2000 time interval, and demonstrates the capability of the SBAS procedure to identify and analyze displacement patterns at different spatial scales for the overall area spanning approximately 5000 km2. Two previously unreported localized deformation effects have been detected at Paoha Island, located within the Mono Lake, and in the McGee Creek area within the Sierra Nevada mountains, a zone to the south of the Long Valley caldera. In addition a spatially extended uplift effect, which strongly affects the caldera, has been identified and analyzed in detail. The InSAR results clearly show that the displacement phenomena affecting the Long Valley caldera have a maximum in correspondence of the resurgent dome and are characterized by the sequence of three different effects: a 1992–1997 uplift background, a 1997–1998 unrest phenomenon and a 1998–2000 subsidence phase. Moreover, the analysis of the retrieved displacement time series allows us to map the extent of the zone with a temporal deformation behavior highly correlated with the detected three-phases deformation pattern: background uplift-unrest-subsidence. We show that the mapped area clearly extends outside the northern part of the caldera slopes; accordingly, we suggest that future inversion models take this new evidence into account. The final discussion is dedicated to a comparison between the retrieved InSAR measurements and a set of GPS and leveling data, confirming the validity of the results achieved through the SBASInSAR analysis

Ground deformation of Long Valley caldera and Mono Basin, eastern California, mapped by satellite radar interferometry

We have illustrated the key results of the Differential SAR Interferometry (DInSAR) analysis focused on the ground deformation of Long Valley caldera and Mono Basin, eastern California. In particular, we have applied the DInSAR algorithm referred to as Small BAseline Subset (SBAS) approach and processed 21 SAR images, spanning the time interval from 1992 to 2000, acquired from descending arbits by the ERS-1 and ERS-2 sensors of the European Space Agency (ESA). The deformation affecting the resurgent dome of Long Valley caldera has been highlighted as well as the previously unreported subsidence of the Pahoa island, located in Mono Lake.Published439–4411.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive3.2. Tettonica attiva4.3. TTC - Scenari di pericolosità vulcanicaJCR Journalreserve

Ground deformation of Long Valley caldera and Mono Basin, eastern California, mapped by satellite radar interferometry

We have illustrated the key results of the Differential SAR Interferometry (DInSAR) analysis focused on the ground deformation of Long Valley caldera and Mono Basin, eastern California. In particular, we have applied the DInSAR algorithm referred to as Small BAseline Subset (SBAS) approach and processed 21 SAR images, spanning the time interval from 1992 to 2000, acquired from descending arbits by the ERS-1 and ERS-2 sensors of the European Space Agency (ESA). The deformation affecting the resurgent dome of Long Valley caldera has been highlighted as well as the previously unreported subsidence of the Pahoa island, located in Mono Lake

Recent advances on tectonics of the Andes and their foreland and southern North America, as part of special issues published in the Journal of South American Earth Sciences in the last three years (2019-20-21)

International audienceThis Editorial is based on the recent advances presented in the Special Issues related to tectonics across South America, released in the last three years. Its objective is to display the intense work focused on different lines of research of the Andean and Pre-Andean tectonic field and also to summarize key aspects extracted from these volumes in one single document. These Special Issues describe recent advances related to supercontinent Gondwana formation and posterior peripheral accretions during the Early Paleozoic, the instalment of coetaneous arc along the paleo-Pacific trench, the development of Late Paleozoic basins in the retro-arc region, Early Mesozoic extension related to the break-up of Gondwana, Late Cretaceous-Cenozoic closure of main retroarc depocenters, conformation of the proto-Andes, the growth of their structure and temporal destabilization during the Cenozoic, exhumation degree, paleoenvironmental changes experienced during these processes, and their neotectonic and seismological behavior. In the following paragraphs we will describe their general content and main achievements reached in these volumes