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Prediction of Engineering Classification of Wedge Terrains of Eastern Ghats
Published in S.P. Kaushish, T. Ramamurthy, Tunnelling Asia’2000, 2020
At some locations of this region revealed that the zone is well foliated, moderately weathered khondalite at some places. The khondalite type of rocks chiefly comprised of quartz-garnet-biotite-silliminate-feldsar gneiss and quartz-feldspar-biotite-garnet-gneiss. Weathered gneiss exposed is of quatz-felaspar-garnet -gneiss. Khondalite rock was considerably decomposed, but physically intact faces were exposed. Also, a shear zone has been encountered. It was uncertain as to how long the shear zone would extend. It consists of clay and rock fragments which were seen from the muck that accumulated in front of the face in the form of a heap from the crown of the Tunnel-23 (K-R Railway line) to the bottom after seeping out of the shear zone.
Site Amplification Factors and Acceleration Response Spectra for Shallow Bedrock Sites – Application to Southern India
Published in Journal of Earthquake Engineering, 2022
The principal rock units of the Eastern Ghats are the granite gneisses, the Charnockite series, the Khondalite series and the granites (GSI). One of the major cities of the Eastern Ghats is Vishakhapatnam (Vizag), the primary soil type of Vizag is clayey to gravelly clayey along with moderately deep dark brown soils. A typical variation of shear wave velocity and bedrock and surface spectra are given in Fig. 6d. It can be observed from Fig. 6d that maximum peak is observed at 0.19 s for this particular site. The PGA value of 0.05–0.13 g has increased to 0.15–0.38 g for the vibration period range of 0.18–0.28 s. A typical variation of shear wave velocity profile and bedrock and surface spectra is given as Fig. 6d. It can be observed from Fig. 6d that maximum peak is observed at 0.10 s for this particular site. Hyderabad forms the part of the Pre-Cambrian peninsular shield and is underlain by the Archaean crystalline complex, comprising Pink and grey granites and granite gneisses. The thickness of soil cover varies from 0.5 to 2.0 m and majorly consist of red lateritic, yellow sandy-clay loams, and alluvial black soils. The amplification of 1.12–2.32 at zero period is increased to 2.85–3.15 at vibration period range between 0.18 and 0.21 s. For most of the sites near to the Eastern Ghats the predominant period is in the range of 0.16–0.28 s.
Raman-XPS spectroscopy, REE chemistry, and surface morphology of Fe-Ti oxide heavy mineral sands: a case study from Varkala-Kovalam coast, south-west India
Published in Applied Earth Science, 2021
R. G. Rejith, M. Sundararajan, A. Peer Mohamed, M. Satyanarayanan
The beach minerals as accessory phases in provenance rocks and the west-flowing rivers originate from Western Ghats act as the geomorphic control for the occurrence of heavy mineral-rich sands along the coast of Kerala. The occurrence of provenance rocks, climatic factors, coastal dynamics and processes, drainage patterns (west-flowing rivers), and coastal geomorphology are driving factors behind the formations of heavy mineral-rich sands. The beach sand transported and deposited over the sea undergoes relative sorting based on their variation in density by the strong action of waves and long currents. Thiruvananthapuram district is mainly occupied by two geological divisions, the Tertiary and Quaternary sediments along the western coastal fringe and the eastern Archean crystalline rocks. The Archean crystalline rocks are composed of khondalites, charnockites, and migmatite groups. The khondalites mainly occupy the southern part of Kerala (including the present study area). It is made of garnetiferous biotite-sillimanite gneiss and rarely calc-granulite and quartzite. The primary sources of heavy minerals are khondalites, charnockites, and also the outcrops of pegmatites and quartz veins seen in these rock types. The Tertiary sediments that linearly stretches along the coast, unconformably overlay the crystalline rocks, are one of the intermediate sources. The laterite weathered from charnockites consists of ilmenite and magnetite, whereas khondalite consists of sillimanite and graphite (Krishnan et al. 2001).
Effect of spatial resolution and data splitting on landslide susceptibility mapping using different machine learning algorithms
Published in Geomatics, Natural Hazards and Risk, 2021
Minu Treesa Abraham, Neelima Satyam, Prashita Jain, Biswajeet Pradhan, Abdullah Alamri
The geology and geomorphology layers are vector files published by GSI. Both the layers are highly significant in the initiation of landslides as the physical processes of landslide triggering are related to the rock type and morphology. Geology explains the bedrock type, while geomorphology explains the interaction of rock with the environment (Youssef et al. 2015). The geology of the region is classified into six categories, viz charnockite group, khondalite group, migmatite complex, peninsular gneissic complex, acid intrusive and basic intrusive (Geological Survey of India 2010). Similarly, there are five prominent categories in geomorphology, i.e., highly dissected hills and valleys, moderately dissected hills and valleys, low dissected hills and valleys, anthropologic terrains and pediment and pediplain complex. From the landslide inventory data, it was observed that more than 70% of the landslides have occurred on terrain which is composed of the migmatite complex and peninsular gneissic complex. These regions are geomorphologically classified as highly and moderately dissected hills and valleys. The vector files were rasterized into two different resolutions, according to the DEM, for a comparative study.