scholarly journals COMPENSATION OF THE IONOSPHERIC EFFECTS ON SAR INTERFEROGRAM BASED ON RANGE SPLIT-SPECTRUM AND AZIMUTH OFFSET METHODS – A CASE STUDY OF YUSHU EARTHQUAKE

2018 ◽  
Vol XLII-3 ◽  
pp. 505-509
Author(s):  
Y. F. He ◽  
W. Zhu ◽  
Q. Zhang ◽  
W. T. Zhang
Keyword(s):  
Surface Deformation ◽  
Low Frequency ◽  
Deformation Monitoring ◽  
Yushu Earthquake ◽  
Ionospheric Effects ◽  
Ground Deformations ◽  
Ionosphere Disturbance ◽  
Geophysical Processes ◽  
Split Spectrum

InSAR technique can measure the surface deformation with the accuracy of centimeter-level or even millimeter and therefore has been widely used in the deformation monitoring associated with earthquakes, volcanoes, and other geologic process. However, ionospheric irregularities can lead to the wavy fringes in the low frequency SAR interferograms, which disturb the actual information of geophysical processes and thus put severe limitations on ground deformations measurements. In this paper, an application of two common methods, the range split-spectrum and azimuth offset methods are exploited to estimate the contributions of the ionosphere, with the aim to correct ionospheric effects in interferograms. Based on the theoretical analysis and experiment, a performance analysis is conducted to evaluate the efficiency of these two methods. The result indicates that both methods can mitigate the ionospheric effect in SAR interferograms and the range split-spectrum method is more precise than the other one. However, it is also found that the range split-spectrum is easily contaminated by the noise, and the achievable accuracy of the azimuth offset method is limited by the ambiguous integral constant, especially with the strong azimuth variations induced by the ionosphere disturbance.

scholarly journals Application of InSAR and gravimetric surveys for developing construction codes in zones of land subsidence induced by groundwater extraction: case study of Aguascalientes, Mexico

2015 ◽  
Vol 372 ◽  
pp. 121-127 ◽  
Author(s):  
J. Pacheco-Martínez ◽  
S. Wdowinski ◽  
E. Cabral-Cano ◽  
M. Hernández-Marín ◽  
J. A. Ortiz-Lozano ◽  
...  
Keyword(s):  
Time Series ◽  
Land Subsidence ◽  
Local Governments ◽  
Surface Deformation ◽  
Geophysical Methods ◽  
Deformation Monitoring ◽  
The State ◽  
Groundwater Extraction ◽  
Hazard Zoning

Abstract. Interferometric Synthetic Aperture Radar (InSAR) has become a valuable tool for surface deformation monitoring, including land subsidence associated with groundwater extraction. Another useful tools for studying Earth's surface processes are geophysical methods such as Gravimetry. In this work we present the application of InSAR analysis and gravimetric surveying to generate valuable information for risk management related to land subsidence and surface faulting. Subsidence of the city of Aguascalientes, Mexico is presented as study case. Aguascalientes local governments have addressed land subsidence issues by including new requirements for new constructions projects in the State Urban Construction Code. Nevertheless, the resulting zoning proposed in the code is still subjective and not clearly defined. Our work based on gravimetric and InSAR surveys is aimed for improving the subsidence hazard zoning proposed in the State Urban Code in a more comprehensive way. The study includes a 2007–2011 ALOS InSAR time-series analysis of the Aguascalientes valley, an interpretation of the compete Bouguer gravimetric anomaly of the Aguascalientes urban area, and the application of time series and gravimetric anomaly maps for improve the subsidence hazard zoning of Aguascalientes City.

scholarly journals Landslide Awareness System (LAwS) to Increase the Resilience and Safety of Transport Infrastructure: The Case Study of Pan-American Highway (Cuenca–Ecuador)

2021 ◽  
Vol 13 (8) ◽  
pp. 1564
Author(s):  
Pietro Miele ◽  
Mariano Di Di Napoli ◽  
Luigi Guerriero ◽  
Massimo Ramondini ◽  
Chester Sellers ◽  
...  
Keyword(s):  
Point Of View ◽  
Transport Infrastructure ◽  
Slope Failures ◽  
Network Systems ◽  
Socioeconomic Impacts ◽  
Economic Point ◽  
Infrastructure Monitoring ◽  
Ground Deformations ◽  
Pan American

In most countries, landslides have caused severe socioeconomic impacts on people, cities, industrial establishments, and lifelines, such as highways, railways, and communication network systems. Socioeconomic losses due to slope failures are very high and they have been growing as the built environment expands into unstable hillside areas under the pressures of growing populations. Human activities as the construction of buildings, transportation routes, dams, and artificial canals have often been a major factor for the increasing damage due to slope failures. When recovery actions are not durable from an economic point of view, increasing the population’s awareness is the key strategy to reduce the effects of natural and anthropogenic events. Starting from the case study of the Pan-American Highway (the Ecuadorian part), this article shows a multi-approach strategy for infrastructure monitoring. The combined use of (i) DInSAR technique for detection of slow ground deformations, (ii) field survey activities, and (iii) the QPROTO tool for analysis of slopes potentially prone to collapse allowed us to obtain a first cognitive map to better characterize 22 km of the highway between the cities of Cuenca and Azogues. This study is the primary step in the development of a landslide awareness perspective to manage risk related to landslides along infrastructure corridors, increasing user safety and providing stakeholders with a management system to plan the most urgent interventions and to ensure the correct functionality of the infrastructure.

Deformation Monitoring in Historic Buildings: A Case Study

Survey Review ◽  
2011 ◽  
Vol 43 (323) ◽  
pp. 484-492 ◽  
Author(s):  
S. Baselga ◽  
P. Garrigues ◽  
J. L. Berné ◽  
A. B. Anquela ◽  
A. Martín
Keyword(s):  
Deformation Monitoring ◽  
Historic Buildings

Do different parasite species interact in their effects on host fitness? A case study on parasites of the amphipod Paracalliope fluviatilis

Parasitology ◽  
2011 ◽  
Vol 138 (9) ◽  
pp. 1176-1182 ◽  
Author(s):  
C. A. RAUQUE ◽  
R. A. PATERSON ◽  
R. POULIN ◽  
D. M. TOMPKINS
Keyword(s):  
Parasite Species ◽  
Low Frequency ◽  
Host Population ◽  
Interactive Effects ◽  
Population Means ◽  
Significant Relationships ◽  
Coitocaecum Parvum ◽  
Paracalliope Fluviatilis ◽  
Generally True

SUMMARYThere is a gap in our understanding of the relative and interactive effects of different parasite species on the same host population. Here we examine the effects of the acanthocephalan Acanthocephalus galaxii, an unidentified cyclophyllidean cestode, and the trematodes Coitocaecum parvum and Microphallus sp. on several fitness components of the amphipod Paracalliope fluviatilis, using a combination of infection surveys and both survival and behavioural trials. In addition to significant relationships between specific parasites and measures of amphipod survival, maturity, mating success and behaviour, interactions between parasite species with respect to amphipod photophilia were also significant. While infection by either A. galaxii or C. parvum was associated with increased photophilia, such increases were negated by co-infection with Microphallus sp. We hypothesize that this is due to the more subtle manipulative effect of A. galaxii and C. parvum being impaired by Microphallus sp. We conclude that the low frequency at which such double infections occur in our sampled population means that such interactions are unlikely to be important beyond the scale of the host individual. Whether or not this is generally true, implying that parasitological models and theory based on single parasite species studies do generally hold, requires cross-species meta-analytical studies.

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