Ques 1: How is damage caused to buildings during an earthquake?
Ans: During an earthquake the ground shakes back and forth due to the plate movement under ground. The surface of the earth ruptures causing huge cracks; landslides occur; and sometimes tsunamis are generated during earthquakes. All these cause severe damage to building. Collapse of buildings, lead to loss of life.
Ques 2: Where are land slides common in India?
Ans: Landslides are a major natural disaster all over the world. In India landslides are common in the hilly regions of the south and in the Himalayan regions of the north. These landslides cause a lot of damage to life and property
Ques 3: Mention the damages caused during a cyclone.
Ans: During cyclones, electricity cables and transmission towers can be damaged causing immense hardship to people. Live electricity wire on the road can prove to be a death trap to people walking on the road. Sign posts on the roads can be damaged.
Ques 4: What causes landslides and what are the warning signs of a landslide?
Ans: Landslides occur due to heavy rainfall, steep slopes, seismic activity and poor drainage.
Landslides are also caused due to deforestation and soil erosions. Unrestricted excavation, mining and quarrying also cause landslides.
Warning signs before a landslide are
Landslides usually occur in the same place again and again. Doors and windows jam for the first time New cracks appear on the walls and floors Gaps form between the pavement and the building outside the house. Fences and compound walls tend to tilt Underground water and electricity lines break
When these warning signs occur people have to take precautions.
Ques 5: What kind of damages are caused to buildings, during floods?
Ans: Small houses and huts are most vulnerable during floods as they get washed away in flood waters. These houses are totally destroyed in the flood waters. Houses which do not have a firm foundation also get washed away or tend to float.
Houses in low lying areas get inundated with water. There is great loss to property in this case. Flood waters can damage the foundation and walls of buildings and this will make the construction weak. Houses may get affected due to floating debris, like huge trees.
Ques 6: What are the features of an earthquake resistant building?
Ans: Features of an earthquake resistant building are as follows:-
Building should have a rectangular plan Reinforced concrete columns should support long walls Large buildings should be fragmented into small rectangular blocks The foundation of the building should be strong. Building constructors should ensure that there is no movement of underground soil once the building is built. Doors and windows should be small and centrally located. This will ensure more stability to the walls. Reinforces concrete bands are essential for all buildings. These bands have to be at the plinth level; floor level; lintel level; and roof level. Vertical reinforcement should be provided at the corners and wall junctions.
Ques 7: How can houses be protected from cyclones?
Ans: To protect houses from cyclones one should select an appropriate site to build a house. The site should be above the inundation level. The shape of an individual building should be either circular or polygonal. Rectangular or square shapes are not suited. A symmetrical building with a compact plan is most suited to withstand cyclones. As cyclones are accompanied by torrential rain inundation is inevitable, so houses should be elevated. Houses should be constructed on stilts or columns.
Doors and windows should have strong closing and locking systems to with stand the force of the wind. Openings just below the roof should be avoided. Glass panelling can be voided in buildings situated in cyclone prone areas. If there are glass panels they have to be protected with paper strips or metallic mesh pasted outside The size of the panels can be small so the damage is minimal. The roof is the most vulnerable part of the building during a cyclone as it is at a higher level and exposed to the wind. Roof projections should be minimal. A pyramidal roof is most suited in cyclone prone areas.