--- title: "Preparation and components of EG map" subject: "Engineering Geology II" chapter: 1 key: "semester_4/engineering_geology_ii:eg-map-preparation" source: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/eg-map-preparation site: BCT Engineering --- # Preparation and components of EG map Engineering Geology II · Chapter 1: Introduction to Engineering Geology - Asked in: 2078 Chaitra, 1.5+1.5 marks; 2074 Bhadra, 1+2 marks; 2076 Bhadra, 1+1 marks; 2071 Bhadra, 3 marks; 2079 Jestha, 2 marks; 2075 Bhadra, 1.5 marks; 2073 Bhadra, 1.5 marks; 2070 Magh, 1 marks; 2077 Chaitra, 1 marks (asked 9 times) - Video: [Geological map | How Geologist make Geologic map | Interpretation and drawing process](https://www.youtube.com/watch?v=CSssmR4d9zk) — Explore 48 - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/eg-map-preparation - Whole chapter: https://www.bctengineer.com/md/semester_4/engineering_geology_ii/chapter-1 ## Question Define engineering geological map. How is it prepared and what are its components? ## Short answer An engineering geological map shows geology classified for civil engineering suitability. It is prepared by desk study, field mapping of lithology, structures, and hazards, plus subsurface and lab data, compiled with cross-sections. Components include topography, lithology, structures, groundwater, geomorphology, hazards, and engineering zoning with legend. ## Answer An **engineering geological map** is a special-purpose map that shows the geology of an area (rock and soil types, structures, groundwater, geomorphology and hazards) in terms of its behaviour and suitability for civil engineering works such as dams, tunnels, roads and bridges. #### Preparation 1. **Desk study:** collect topographic sheets, geological maps, aerial photos/satellite images and old reports; decide scale (1:50,000 for regional, 1:5,000 to 1:1,000 for a site). 2. **Base map:** enlarge or prepare a topographic base map with contours and coordinates. 3. **Field mapping:** traverse the area, record lithology, contacts, strike and dip, joints, faults, folds, weathering grade, springs, slope condition, landslides and erosion. 4. **Sub-surface data:** add data from test pits, trenches, drill holes, geophysical surveys and tunnel/adit logs. 5. **Laboratory/field tests:** rock and soil strength, permeability, rock mass classification (RMR, Q). 6. **Compilation:** transfer all data to the base map, draw boundaries, then add cross-sections and engineering zoning. 7. **Interpretation and report:** classify the ground into engineering units and give recommendations. #### Components - Topographic base (contours, rivers, roads, settlements, north arrow) - Lithological units with age, grain size, hardness and weathering - Structural data: strike/dip symbols, joints, faults, folds, shear zones - Soil/overburden type and thickness - Hydrogeology: springs, water table, seepage zones - Geomorphology and hazards: landslides, rock falls, flood limits, active faults - Engineering classification/zoning of rock mass and sites (good, fair, poor) - Legend, scale, title, cross-sections and explanatory notes ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What makes an engineering geological map different from other maps? A. It shows geology in terms of behaviour and suitability for civil works B. It shows only rock ages and fossils C. It shows only contour lines and roads D. It shows only groundwater levels Answer: A. It is a special-purpose map presenting geology (rocks, soil, structure, water, hazards) in terms of suitability for dams, tunnels, roads and bridges. (Key point: Definition) 2. Which step comes first when preparing the map? A. Field traverse and mapping B. Desk study of existing maps, photos and reports C. Drawing cross-sections D. Writing recommendations Answer: B. Preparation begins with a desk study (topographic sheets, geological maps, aerial photos, old reports) and choice of scale. (Key point: First step of preparation) 3. Why are test pits, trenches and drill holes added during preparation? A. To draw contours on the base map B. To replace field mapping completely C. To supply sub-surface information that surface mapping cannot show D. To choose the north arrow Answer: C. Surface mapping alone cannot show what lies below, so pits, trenches, boreholes, geophysics and adit logs add sub-surface data. (Key point: Sub-surface data) 4. Which is a component of an engineering geological map? A. Only the legend B. Engineering zoning of rock mass and sites as good, fair or poor C. Only the drill-hole cost D. Only the stratigraphic age column Answer: B. Components include a topographic base, lithology, structure, soil, hydrogeology, hazards, engineering zoning, legend, scale and cross-sections. (Key point: Components) ## Related in Engineering Geology II - [EG map versus geological map](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Aeg-map-vs-geological-map) — Engineering Geology II, chapter 1 - [Types and uses of EG map](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Aeg-map-types-uses) — Engineering Geology II, chapter 1, asked 3× - [Engineering geological problems of Siwalik zone](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Asiwalik-problems) — Engineering Geology II, chapter 2, asked 4× - [Topographical and geological maps for materials](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Amaps-construction-materials) — Engineering Geology II, chapter 7, asked 7× - [Detail stage of EG site investigation](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Adetail-stage-investigation) — Engineering Geology II, chapter 4 ## Related in other subjects - [Engineering geological map and site investigation](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aengineering-geological-map-and-site) — Engineering Geology I, chapter 1, asked 3× - [Site preparation components and facility arrangement](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Asite-preparation-facilities-urban) — Construction Management, chapter 6 - [Components of site preparation](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Asite-preparation-components) — Construction Management, chapter 6 - [Engineering geological problems in tectonic divisions](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aengineering-geological-problems-in-tectonic) — Engineering Geology I, chapter 7, asked 2×