Important Questions with Answers

ANNA UNIVERSITY Part - A '2' Marks Q & A

 

1. What are the causes of hazards ?

Some of the hazards which cause environmental degradation are floods, earth-quakes, cyclones, landslides, drought, etc.

 

2. What are the types of hazards?

Hazards are classified into two categories:

(i) Natural hazards

(ii) Anthropogenic hazards.

 

3. What are natural hazards ?

• Air-related hazards: Hurricanes, cyclones, storms, etc.

• Water-related hazards: Floods, droughts, etc.

• Earth-related hazards: Earthquakes, landslides, volcanoes,

 

4. What are anthropogenic hazards?

• Industrial accidents

• War, riots, acts of terrorism, etc.

• Toxic spills

 

5. What is earthquake?

An earthquake is caused by a portion of the rigid crust of the earth giving way, or getting fractured, some distance below its surface.

 

6. Define focus and epicentre of earthquake ?

The place where the actual fracture occurs is called the focus of the earthquake. It is not a geometrical point, but an extended region. The point nearest to the focus on the surface of the earth is called the epicentre.

 

7. What are the causes of earthquake ?

• Sudden movement of hot gases and magma

• Volcanic activities

• Stress caused by water pressure in dams

• Tectonic stress generated by movement of tectonic plates

 

8. What are the types of earthquake?

The earthquakes can be classified into three categories based on its depth of focus. These are:

(i) Shallow focus earthquakes are earthquakes with depth of focus less than 70 km. Nearly 80% of total earthquakes are shallow focus earthquakes.

(ii) Intermediate focus earthquakes are earthquakes with depth in the range of 70 - 300 km.

(iii) Deep focus earthquakes are earthquakes having focal depth greater than 300 km.

 

9. Define intensity of earthquake.

Intensity is a qualitative measure of the strength of an earthquake. It gives a gradation of strength of earthquake using observed damage to structures and/or ground and reaction of humans to the earthquake shaking.

 

10. Define magnitude of earthquake.

The magnitude is a quantitative measure of the size of an earthquake. It can be correlated to the amount of wave energy released at the source of an earthquake.

 

11. What are the effects of earthquake?

1. Ground shaking

2. Liquefaction of ground disse edit to elonio egud a to

3. Ground displacementre lo aqy od os adW .81

4. Land slides

5. Flood

6. Fire

7. Tsunami

 

12. What are seismic waves?

A number of different types of waves, collectively called seismic waves orginate from the focus, (regard as a point). These waves spread on to different points on the surface of the earth and which appears as 'earthquake tremors'.

 

13. What are the types of seismic waves?

(i) Body waves

 (a) Primary waves

 (b) Secondary waves

(ii) Surface waves.

(aoo) (a) Rayleigh waves

(b) Love waves

 

14. What are primary waves?

These are longitudinal waves, in which the particles of the earth vibrate about their mean position, along the direction of the waves themselves. To

If the earth is regarded to be a homogeneous sphere, these waves, starting from the focus, travel along the chord of huge circle of the earth.

 

15. What are secondary waves?

These are transverse waves. That is the particles of the earth vibrate at right angles to the direction of propagation of the waves.

Starting from the focus, these waves travel along a chord of a huge circle of the earth.

 

16. What are the types of surface waves?

(a) Rayleigh waves

(b) Love waves.

 

17. Define Rayleigh waves.

These waves are found to remain confined to a comparatively thin layer in the close vicinity of the earth's surface.

Unlike the P and S waves, they start from the epicentre and arrive at the observing station along a huge circle of the earth.

The displacement of the particles is being in the vertical plane containing their direction of propagation.

 

18. Define love waves.

The heterogeneity of the layers of the earth is also responsible for another type of surface waves, known as love waves.

In this waves, the displacement of the earth is horizontal, but transverse to the direction on their propagation.

 

19. What is seismology?

The study of the seismic waves constitutes the science of Seismology. It deals with earthquakes and seismic waves that move through and around the earth.

 

20. What are the applications of seismology?

(i) Investigation of the nature of the interior of the earth,

(ii) Prospecting for oils and minerals,

(iii) Construction of earth quake-proof buildings

(iv) Forecasting of the occurrence

 

21. What is seismic hazard?

It is defined as any physical phenomenon, such as ground shaking or ground failure. It is associated with an earthquake and that, may produce adverse effects on human activities.

 

22. What is seismic hazard analysis?

Seismic hazard analysis involves the quantitative estimation of ground shaking hazards at a particular area.

 

23. Mention the most important factors affecting seismic levis hazard at a location.

1. Earthquake magnitude

2. Source-to-site distance

3. Earthquake rate of occurrence (return period)

4. Duration of ground shaking

 

24. What are the types of seismic hazard analysis?

Seismic hazard is analyzed in two ways

(i) Deterministically, (as when a particular earthquake scenario is assumed),

(ii) Probabilistically, (in which uncertainties in earthquake size, location, and time of occurrence are explicitly considered).

 

25. What is deterministic seismic hazard analysis?

It is done for a particular earthquake, either assumed or Jadi realistic.

• DSHA approach uses the known seismic sources sufficiently near the site and available historical seismic and geological data. These data are used to generate discrete, single-valued events or models of ground motion at the site.

 

26. What are the steps in DSHA?

(i) Identification and characterization of all sources.

(ii) Selection of source-site distance parameter

(iii) Selection of the "controlling earthquake”

(iv) Definition of hazard using controlling earthquake

 

27. What is probabilistic seismic hazard analysis?

Probabilistic seismic hazard analysis (PSHA) provides a framework in which these uncertainties can be identified, quantified, and combined in a rational manner to provide a more complex picture of the seismic hazard.

 

28. What are the four steps in PSHA?

(i) Identification and Characterisation of  earthquake sources.

(ii) Characterisation of temporal distribution of earthquake recurrence.

(iii) Determination of grand motion.

(iv) Computation of probability of earthquake.

 

29. What is cyclone?

Cyclones are huge revolving storms in the atmosphere with very strong winds circulating round a central area.

 

30. What is a storm surge?

A storm surge is an abnormal rise of sea level near the coast due to which sea water inundates low-lying areas of coastal region. It causes damage to human life and property.

 

31. How are cyclones classified?

They are classified as

 (i) Extra tropical cyclones (temperature cyclones) and

(ii) Tropical cyclones.

 

32. What are the categories of cyclone based on wind speeds and their capacity to cause damage?

Cyclones are classified into five different levels on the basis of wind speed.

 

33. What are the effects of cyclones?

• Cyclones are associated with high pressure gradients and consequent strong winds, which, in turn, generate storm This causes sea water to inundate low-lying area sdsupd of coastal regions drowning human beings and livestock.

• This erodes beaches and embankments.

• It also destroys vegetation and reduces soil fertility.

• Very strong winds associated with cyclones may damage installations, dwellings, communication systems, trees, etc., resulting in loss of life and property.

 

34. What are the preventive measures of cyclone?

Some long term defence measures can help to protect us from devastation. Such measures include

• planting more trees on the coastal belt,

• construction of dams, strom shelter, wind breaks,

• proper drainage and wide roads for quick evacuation.

• Forecasting a cyclonic event is the best measure of minimizing the losses due to a cyclone.

 

35. What is flood hazard ?

The accumulation of large quantity of water at a place or the presence of more water than what can be handled by the drainage of the area is known as flood.

 

36. What are the types of floods ?

There are 3 types of floods.

(i) Flash flood

(ii) River flood

(iii) Coastal flood as

 

37. What are the causes of floods?

• Heavy rain for a very short period result in floods.

• River can overflow their banks to cause flooding, as it flows downstream to the adjacent low lying areas, there riw be is a burst and water gets into the land.

• Sea water can be carried by massive winds and hurricanes on to dry coastal lands.

 

38. State the effects of flood hazards.

Floods can have devastating consequences and can have effects on the economy, environment and people.

Primary hazards are the effects of floods due to direct contact with the flood waters.

 

39. Mention the methods of flood prevention.

The intensity of flood can be minimized using the following measures.

• Plantation on slopes

• Drainage management

• Flood-plain zoning

• Forecasting

 

40. What is fire hazard ?

Fire hazards include all types of live flames, causes of sparks, hot objects and chemicals that are potential for ignition, or aggravate a fire to become large and uncontrolled.

Fire hazards also include all types of potential threats to fire prevention practices.

 

41. What are the types of fire hazards?

1. Exposure hazard

2. Internal hazard

3. Personal hazard

 

42. Mention the causes of fire.

• Improper storage of inflammable materials in and around

• Heating sources are often causes of fire - space heaters, electrical heaters and fireplaces should be used with caution.

• Cooking accidents.

• Smoking.

• Electrical wiring.

• Rubbish and waste materials.

 

43. What is fire protection?

• Fire protection is the study and practice of mitigating the unwanted effects of potentially destructive fires.

• It involves the study of the behaviour, compartmentalisation, suppression and investigation of fire and its related emergencies.

 

44. What are the types of fires based on the kind of combustible material ?

(a) Class A: Ordinary material

Example wood, paper, textile and rubbish.

(b) Class B: Flammable liquids

Example oils and greases.

 (c) Class C: Live electrical equipments.

 

45. Define fire proofing.

Fire proofing is a type of fire protection measure. It refers to the act of allowing materials to be more resistant to fire outbreaks.

 

46. Mention a few fire proofing materials.

The fire-resisting building materials are stone, brick, cast-iron, glass, steel and concrete

 

47. What is fire fighting ?

It is an act of attempting to prevent the spread of and extinguish unwanted fires in buildings, vehicles, wood land etc.

 

48. What are fire safety regulations?

All buildings should satisfy certain requirements which contribute, individually and collectively, to the safety of life from fire, smoke, fumes etc. There are however, certain general principles and common requirements which are applicable to all or most of the occupancies. These principles are called safety regulations.

 

ANNA UNIVERSITY Part B (16 Marks) Questions

1. Discuss earthquake ground motion with types, intensity and magnitude.

2. Explain seismic waves and seismology.

3. Describe earthquake site effect.

4. Explain deterministic seismic hazard analysis and probabilistic seismic hazard analysis.

5. Explain cyclone hazard with cause and effect. Write preventive measures of cyclone.

6. Explain flood hazards. Mention the effects and methods of flood prevention.

7. Explain fire hazards and fire protection.

8. Describe fire proofing of materials.

9. Discuss fire fighting equipments.

10. Write a note on fire safety regulation.

11. Discuss fire prevention and safety measures.

1. Direct sound transmission

2. Flanking transmission

3. Overhearing

4. Leakage

 

Methods of sound insulation

The method of sound insulation will depend on the type of noise to be treated and the degree of sound insulation required. The methods of sound insulation can thus be classified into three main categories.

 

1. When the source of noise is in the room itself.

2. When noise is air-borne.

3. When noise is structure-borne.

 

1. When source of noise is in the room itself

Following are the methods of sound insulation which are commonly used when the source of noise is situated in the room to be treated for sound insulation.

 

(i) Improvement in working methods iau va

(a) A working method creating less noise may be adopted. For instance, welding may be preferred to riveting.