Multi-sensor remote sensing analysis of coal fire induced land subsidence in Jharia Coalfields, Jharkhand, India

The subsidence in coal mines induced by surface and subsurface fires leading to roof collapse, infrastructure loss, and loss of lives is a prominent concern. In the study, satellite imagery from thermal and microwave remote sensing data is used to deduce the effect of coal fires on subsidence in the Jharia Coalfields, India. The Thermal Infrared data acquired from the Landsat-8 (band 10) is used to derive the temperature anomaly maps. Persistent Scatterer Interferometry analysis was performed on sixty Sentinel-1, C-band images, the results are corrected for atmospheric error using Generic Atmospheric Correction Online Service for InSAR (GACOS) atmospheric modelling data and decomposed into vertical displacement values to quantify subsidence. A zone-wise analysis of the hazard patterns in the coalfields was carried out. Coal fire maps, subsidence velocity maps, and land cover maps were integrated to investigate the impact of the hazards on the mines and their surroundings. Maximum subsidence of approximately 20 cm/yr. and temperature anomaly of up to 25 °C has been observed. The findings exhibit a strong positive correlation between the subsidence velocity and temperature anomaly in the study area. Kusunda, Keshalpur, and Bararee collieries are identified as the most critically affected zones. The subsidence phenomenon in some collieries is extending towards the settlements and transportation networks and needs urgent intervention. © 2021 The Author

Geomática aplicada al análisis de riesgos geológicos

Tesis por compendio de publicaciones[ES]Esta Tesis Doctoral se ha realizado mediante el formato de compendio de artículos, con objetivos claramente diferenciados y concatenados entre sí con el fin de ampliar el conocimiento sobre la implementación de nuevas metodologías en Geomática Aplicada utilizando información de uso público para la gestión de la peligrosidad natural en la reducción del Riesgo Geológico. Se ha puesto énfasis en hacer conocer a la comunidad los beneficios de analizar los riesgos geológicos con anticipación para identificarlos espacialmente y establecer correcciones estructurales como criterio de prevención, lo que implica elaborar previamente mapas de zonas susceptibles a movimientos en masa, inundaciones, erosión hídrica, mapas sismo-tectónicos-volcánicos y de problemas geotécnicos, a partir de la Geomática Aplicada (Teledetección, Sistemas de Información Geográfica y Modelación Numérica) e información espacial georeferenciada. Se desarrollan en esta Tesis cinco métodos geomáticos aplicados a la reducción del riesgo geológico, validados mediante su aplicación en diferentes riesgos geológicos de varias regiones de Ecuador[EN][EN]This Doctoral Thesis has been carried out through the compendium format of articles, with clearly differentiated and concatenated objectives in order to expand knowledge on the implementation of new methodologies in Applied Geomatics using information of public use for the management of natural hazard in the reduction of Geological Risk. Emphasis has been placed on making the community aware of the benefits of analyzing geological risks in advance to spatially identify them and establish structural corrections as a prevention criterion, which implies preparing previously maps of areas susceptible to mass movements, floods, water erosion, Earthquake-tectonic-volcanic maps and geotechnical problems, from Applied Geomatics (Remote Sensing, Geographic Information Systems and Numerical Modeling) and georeferenced spatial information. Five geomatic methods applied to the reduction of geological risk are developed in this thesis, validated by their application to different geological risks in various regions of Ecuador

Mapping Land Subsidence Related to Underground Coal Fires in the Wuda Coalfield (Northern China) Using a Small Stack of ALOS PALSAR Differential Interferograms

Coal fires have been found to be a serious problem worldwide in coal mining reserves. Coal fires burn valuable coal reserves and lead to severe environmental degradation of the region. Moreover, coal fires can result in massive surface displacements due to the reduction in volume of the burning coal and can cause thermal effects in the adjacent rock mass particularly cracks and fissures. The Wuda coalfield in Northern China is known for being an exclusive storehouse of prime coking coal as well as for being the site of occurrence of the maximum number of known coal fires among all the coalfields in China and worldwide, and is chosen as our study area. In this study, we have investigated the capabilities and limitations of ALOS PALSAR data for monitoring the land subsidence that accompanies coal fires by means of satellite differential interferometric synthetic aperture radar (DInSAR) observations. An approach to map the large and highly non-linear subsidence based on a small number of SAR images was applied to the Wuda coalfield to reveal the spatial and temporal signals of land subsidence in areas affected by coal fires. The DInSAR results agree well with coal fire data obtained from field investigations and thermal anomaly information, which demonstrates that the capability of ALOS PALSAR data and the proposed approach have remarkable potential to detect this land subsidence of interest. In addition, our results also provide a spatial extent and temporal evolution of the land subsidence behavior accompanying the coal fires, which indicated that several coal fire zones suffer accelerated ongoing land subsidence, whilst other coal fire zones are newly subsiding areas arising from coal fires in the period of development