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Showing posts from August, 2024

Explore the Earth, Maps and Satellite Images

Google Maps and Google Earth are very common platforms today to explore maps and satellite images of the earth. But there are many other ways to explore the earth. Some are listed here.  1.   Earth Explorer This map is developed by USGS helpful to obtain earth imagery across available geo-spatial data types. Users can navigate via interactive map or text search to obtain Landsat satellite imagery, Radar data, UAS data, digital line graphs, digital elevation model data, aerial photos, Sentinel satellite data, some commercial satellite imagery including IKONOS and OrbView3, land cover data, digital map data from the National Map, and many other datasets. Users can search by exact location via the interactive map or input specific coordinates to view what data types are available. 2.   Sentinel Hub This platform developed by  Sinergise has Sentinel, Landsat, and other Earth observation imagery easily accessible for browsing, visualization and analysis. It can automatically archi

Seismic Survey: Notes of major uses

  Seismic Survey Suitable for mapping of layered sedimentary sequences Widely used in search of oil and gas. Small scale mapping of near surface sedimentary layers , location of water table,  Site investigation of foundation conditions (including depth of bedrock). In engineering site investigation, Vp and Vs measurement for near surface layers allows direct calculation of Poisson's ratio and estimation of elastic moduli, which provides valuable information on in situ geotechnical properties. Offshore geological surveys Refraction Reflection ( most widely used geophysical technique) Large/regional scale experiments for study of the entire crust or lithosphere. Estimation of depth of bedrock in foundation site investigation. In engineering purpose, derive relation between velocity and hardness of rock for quarrying operations, nature of landfill materials. Exploration of underground water in conjunction with resistivity methods (as there is a large difference in velocity of dry and