In this paper, a new way of characterizing the mining-driven complex geological deformations is presented by utilizing a continuous real-time microseismic (MS) data acquired through passive seismological monitoring. The data was processed, and the source parameters were computed encompassing over 60,000 MS events. The correlation between MS events and regional stratigraphy reveals that the Upper and Middle Xishanyao Formations substantially contributed to induced seismicity. Most of the high-energy events (>3000 J) are located between 1200 and 1400 m in the coal seams and above, indicative of formation of the macrofracture in the roof rock layers perturbing the limits required for the equilibrium state of roof structure. Taking advantage of the recorded events, a large number of induced fractures are mapped and interpreted associated lineaments and their deformation mechanism is discussed. The correlation of mapped fractures and lineaments with MS energy showed an extremely erratic and complicated pattern revealing the different levels of accumulated stress. Based on the orientation and geometry, regional lineaments were classified into two broad systems that provided guidance for determining the propagation directions of the deformation. Based on the in-depth analysis of fractures and lineaments, a new fault is identified with m and various splays oriented in different directions serving as a new tool in rock engineering. An upsurged shear stress and decreased normal stress along the fault may lead to enhanced induced seismicity. Furthermore, a total of 5 vulnerable zones are identified as an example offering insights for worldwide geohazard assessments.
27 June 2012 in Environmental Monitoring and Assessment
Open and non-engineered dumping is a typical method for solid waste disposal in most cities of Pakistan. This practice of waste dumping poses a serious threat to the surrounding ecosystem and human population due to the release and transport of decomposed organic matter, i.e., leachate from dumpsite into the groundwater. The present study was conducted over a non-engineered and open dumpsite (Chowa Gujar), located in the outskirts of the highly populated city of Peshawar by using integrated geophysical techniques such as electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) and geochemical techniques. The main goal was to delineate the characterization and depth of buried waste, to map the subsurface extension of contaminant plumes towards agricultural land and groundwater table and the concentration of heavy metals (HMs) in dump and agricultural soil. Geophysical results showed that the thickness of buried waste (predominantly composed of domestic waste) was around 4 m and the leachate plumes have percolated to the adjacent agricultural land. A range of heavy metals (mg/kg) such as Cr (20.5–26.6), Cd (2.6–5.7), Pb (0.35–21.25), Ni (2.5–53.05), Cu (29–68.3), Zn (45.7–77), and Co (18.9–23.2) have been found in the agricultural land adjacent to the dumpsite. The findings demonstrated that combined use of ERT and GPR successfully characterize the buried waste and spread of pollutant plumes spatially and vertically from Chowa Gujar dumpsite. The anomalous geophysical signatures were confirmed by geochemical characterization. The movement of leachate plumes towards agricultural land and groundwater table and the concentration of HMs in soil show that Chowa Gujar dumpsite is a potential source of contamination not only to the surrounding population but also to the agricultural land, surface (Bara River), and subsurface water bodies. In the study region, there is an urgency to take remediation and mitigation measures to reduce the level of pollution created by the dumpsite.