geological disasters.pptx

disasters sub topic

1. Geological Disasters BY Dr.D.S.Vijayan AVIT

2. What are geological disasters A natural disaster due to geological disturbances, often caused by shifts in tectonic plates and seismic activity Examples Earthquakes, landslide, volcanic eruptions, avalanches

3. Contents Avalanches Landslides Earthquakes Volcanic eruptions

4. Avalanches Avalanche Large mass of rock debris or snow that moves rapidly down a mountain slope, sweeping and grinding everything in its path.

5. How they are created  An avalanche begins when a mass of material overcomes frictional resistance of the sloping surface, often after its foundation is loosened by spring rains or is rapidly melted by warm, dry wind. Vibrations caused by loud noises, such as artillery, thunder, or blasting can create an avalanche. Avalanches usually occur in February, March, and January. They can also occur in April when everything thaws.

6. Areas in the world where Avalanches Occur  Avalanches can occur anywhere in the world. They occur where ever there is a high snow covered mountain. Avalanches can also occur near plate boundaries. Usually at convergent plate boundaries.

7. Damage Due to Avalanches Avalanches don’t do a lot of damage to cities or towns because they are up in the high mountains but anything up there better watch out. Avalanches burry mountain side homes and destroy forests. They also take down radio towers and lodges that are in its path. Avalanches also take away people’s lives, especially skiers who are taking a trip down the mountain.

8. Tips on Avalanches If you are in an area that is highly at risk for avalanches be sure not to ski or use any snowmobiles on the mountain. Try not to use any explosives around an avalanche zone. If there was a heavy snow fall the night before make sure not to go on the mountain because you might trigger an avalanche. Don’t ever go alone on a mountain that has been known to have avalanches.

9. Future Research They are doing research to find out about the mechanisms that govern the build-up of snow - wind and precipitation - instability within the snow cover, and the flow of avalanches. The main objective of this research is to improve zoning and make defenses more effective and more reliable.

10. Landslide A landslide is an catastrophic event where a block of earthen mass slides downhill. Cause significant loss of life and billions of dollars each year

11. Landslides Prediction Although a basic understanding of the landslides is available, system that predict the occurrence of a landslide do NOT exist. Why? The lack of field measurements over large temporal and spatial scales.

12. How they occur Natural causes of Landslides Earthquakes Heavy Rainfall Human causes of Landslides Clear Cutting Mining

13. Earthquakes Seismic activities have always been a main cause of landslides throughout the world. Any time plate tectonics move the soil that covers them moves with it. When earthquakes occur on areas with steep slopes, many times the soil slips causing landslides.

14. Heavy Rainfall When sloped areas become completely saturated by heavy rainfall many times landslides can occur. Without the aid of mechanical root support the soil simply runs off when it contains too much water.

15. Human causes of Landslides Clear Cutting: Method of timber harvesting which completely removes all old growth timber from the area. This method is hazardous because it destroys the existing mechanical root structure in the area. Mining : Mining operations that use blasting techniques often cause other areas that are at the risk of sliding to slide due to vibrations under the soil.

16. Before the occurrence of landslide In terms of economic aspects, the government needs to upgrade more on the knowledge on natural phenomenon to the public through media such as internet, seminar and others. By stating more information regarding the landslide, the locals would know few things about landslide and the way to deal with landslide if it occurs. Not only that, the government should provide more expertise to prevent this matter before it happens. In addition, with expertise help, the government should held campaign for the locals to participate. Therefore, the locals can gain knowledge on this matter.

17. Before the occurrence of landslide In term of social aspects, the locals need to understand and apply their knowledge about the occurrence of landslide. The locals must aware about their areas especially the area that are near steep slopes, lose to mountain edges, near drainage ways or natural erosion valleys. As mentioned earlier that the government should provide knowledge about landslide, the locals should take precautious about their property, such as the locals should contact the expertise and as for information their property that whether their area are prone to landslide or not.

18. After the occurrence of landslide  In terms of economical aspects, house owners should choose housing insurance companies that can cover damages caused by landslide if they feel that their houses are prone to landslide. This would ease the burden of the victims in financial terms. In terms of infrastructure aspect, retaining walls should be checked for damages quite often to ensure that it is properly functioning. The surrounding areas of the retaining walls should also be included in this maintenance process. For instance checking whether the wall retentions' holes are blocked or not.

19. Planning action we were asked to plan some actions regarding our projects. The actions will be executed individually and these are the action plan that will be executed Insurance coverage Creating a blog Plantation of trees

20. Earthquake An Earthquake is the result of a sudden release of energy in the earth’s crust that creates seismic waves. The seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.

21. Causes Of Earthquake The primary cause of an earthquake is faults on the crust of the earth. “A Fault is a break or fracture b/w two blocks of rocks in response to stress.” This movement may occur rapidly, in the form of an earthquake or may occur slowly, in the form of creep. Earth scientists use the angle of the fault with respect to the surface and the direction of slip along the fault to classify faults.

22. Earthquake Prediction Unusual animal behaviour Water level in wells Large scale of fluctuation of oil flow from oil wells Foreshocks or minor shocks before major earthquake Temperature change Uplifting of earth surface Change in seismic wave velocity

23. Effect Of Earthquake Loss of life and property Damage to transport system i.e. roads, railways, highways, airports, marine Damage to infrastructure. Chances of Floods – Develop cracks in Dams Chances of fire short-circuit. Communications such as telephone wires are damaged. Water pipes, sewers are disrupted Economic activities like agriculture, industry, trade and transport are severely affected.

24. Earthquake Safety Rules Don’t use lift for getting down from building. Be prepared to move with your family. If you are in shop, school or office Don’t run for an exit. Take cover under a desk/table. Move away from window glass. Do not go near electric point and cable. Keep away from weak portion of the building .

25. After An Earthquake Keep calm, switch on the transistor radio and obey instructions. Keep away from beaches and low banks of river. A huge wave may sweep in Do not re enter badly damaged buildings and do not go near damage structures. Turn off the water, gas and electricity. Do not smoke, light match or use a cigarette lighter Do not turn on switches there may be gas leak or short circuit If there is any fire, try to put it out or call fire brigade.

26. Local response The response within India was immediate. The national and state governments quickly provided assistance in many forms including cash, medical supplies, communications teams, shelters, food, clothing, transport and relief workers.

27. Volcanic eruption A volcano is a rupture on the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.

28. Cause of eruption As rock inside the earth melts, its mass remains the same while its volume increases--producing a melt that is less dense than the surrounding rock. This lighter magma then rises toward the surface by virtue of its buoyancy. If the density of the magma between the zone of its generation and the surface is less than that of the surrounding and overlying rocks, the magma reaches the surface and erupts.

29. Safety Tips Stay away from active volcanoes. If you live near an active volcano, keep goggles and a mask in an emergency kit, along with a flashlight and a working, battery-operated radio. Know your evacuation route. Keep gas in your car.

30. If a Volcano Erupts in Your Area • Evacuate only as recommended by authorities to stay clear of lava, mud flows, and flying rocks and debris. Avoid river areas and low-lying regions. Before you leave the house, change into long-sleeved shirts and long pants and use goggles or eyeglasses, not contacts. Wear an emergency mask or hold a damp cloth over your face.

31. If a Volcano Erupts in Your Area If you are not evacuating, close windows and doors and block chimneys and other vents, to prevent ash from coming into the house. Be aware that ash may put excess weight on your roof and need to be swept away. Wear protection during cleanups. Ash can damage engines and metal parts, so avoid driving. If you must drive, stay below 35 miles (56 kilometers ) an hour.

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