HAZARDS, DISASTERS AND YOUR COMMUNITY - PreventionWeb
Version 1.0 HAZARDS, DISASTERS AND YOUR COMMUNITY A PRIMER FOR PARLIAMENTARIANSGovernment of IndiaMinistry of Home AffairsNational Disaster Management Division“towardssaferINDIA”
HAZARDS, DISASTERS AND YOUR COMMUNITY VERSION 1.0A PRIMER FOR PARLIAMENTARIANSPublished by National Disaster Management Division, Ministry of Home Affairs, Government ofIndia“towardssaferINDIA”2
This document is prepared by Prof Anand S Arya, Anup Karanthand Ankush Agarwal under the GoI-UNDP Disaster Risk Management Programme“towardssaferINDIA”3
CONTENTSCHAPTER1HAZARDS AND DISASTERS5CHAPTER2EARTHQUAKES HAZARDS AND DISASTERS9CHAPTER3TSUNAMI HAZARDS AND DISASTERS14CHAPTER4LANDSLIDE HAZARDS AND DISASTERS18CHAPTER5CYCLONE HAZARDS AND DISASTERS24CHAPTER6FLOOD HAZARDS AND DISASTERS31CHAPTER7DROUGHT HAZARDS AND DISASTERS36CHAPTER8FOREST FIRE HAZARDS AND DISASTERS39CHAPTER9CHEMICAL AND INDUSTRIAL ACCIDENTS44CHAPTER 10OTHER TYPES OF NATURAL HAZARDS AND DISASTERS46CHAPTER 11EFFECTS OF NATURAL HAZARD ON ECONOMY & DEVELOPMENT51CHAPTER 12ROLE OF POLICY MAKERS IN DISASTER RISK REDUCTION55ANNEX ADISASTER MANAGEMENT – INSTITUTIONAL ARRANGEMENTS ININDIA57ANNEX BLIST OF RESOURCE INSTITUTIONS60“towardssaferINDIA”4
CHAPTER 1HAZARDS AND DISASTERSWHAT IS A HAZARD? HOW IS IT CLASSIFIED?A dangerous condition or events that threaten or have the potential for causing injury to life or damage toproperty or the environment. They can be categorized in various ways but, based on the origin, hazardsworldwide are basically grouped in two broad headings:1. Natural Hazards (hazards with meteorological, geological or even biological origin)2. Unnatural Hazards (hazards with human-caused or technological origin)It is also important to know that natural phenomena are extreme climatological, hydrological, orgeological, processes that do not pose any threat to persons or property. A massive earthquake in anunpopulated area, for example, is a natural phenomenon, not a hazard. It is when these naturalphenomena interact with the man made environment or fragile areas which causes wide spread damage.WHAT ARE DISASTERS?Almost everyday we witness in the newspaper or on the TV, there are reports of disasters around theworld. So what are disasters? How are they different from accidents? Disaster is defined as:",,,,,a serious disruption of the functioning of a society, causing widespread human, material, orenvironmental losses which exceed the ability of the affected society to cope using its own resources."A disaster is the product of a rm coinciding with a deDynamicPressureare two main components in thisdefinition: hazard and vulnerability.Without vulnerability or hazard there isno disaster. A disaster occurs whentowardssaferTrigger nesVolcanic eruptionDroughtLandslideWarTechnological accidentEnvironmental pollution DangerouslocationDangerousbuildingsLow incomelevel .Lack of- institutions- education- training- evelopmentEnvironmentaldegradation Limitedaccess toresourcesIllness anddisabilitiesAge/sexPoverty .communities, cities or villages. There“HazardDISASTERINDIA”5
hazards and vulnerability meet. See the figure along with underlying issues under each.There are several important characteristics that make Disasters different from Accidents. The loss of asole income earner in a car crash may be a disaster to a family, but only an accident to the community.Variables such as Causes, Frequency, Duration of the Impact, Speed of Onset, Scope of the Impact,Destructive Potential, Human Vulnerability etc determine the difference.WHAT IS VULNERABILITY?Vulnerability is defined as “The extent to which a community, structure, service, or geographic area islikely to be damaged or disrupted by the impact of particular hazard, on account of their nature,construction and proximity to hazardous terrain or a disaster prone area."Now take for example a house built from cane and thatch and the other a brick building. The house builtfrom cane and thatch that can be blown in a tropical cyclone are more vulnerable to the wind than a brickbuilding. A badly constructed brick building is more likely to disintegrate with the violent ground shakingof an earthquake than cane or thatch hut and is more vulnerable to earthquake hazard. Hence structuresshould be built strong enough to resist maximum force exerted by any event or for combination of event.Such measure will take care of the physical vulnerability.Social and economic conditions also determine the vulnerability of a society to an extent. It has beenobserved that human losses in disasters in developing countries like India tend to be high whencompared to developed countries where material losses predominate.See the figurewhere thesettlementslocatedhazardousareslopes.inUnstable slopeManylandslide and flooding disastersare linked to what you see inriverSitethe figure below. Uncheckedrivergrowth of settlements in unsafeSite after pressures from population growth and urbanizationareas exposes the people to thehazard. In case of an earthquake or landslide the ground may fail and the houses on the top may toppleor slide and affect the settlements at the lower level even if they are designed well for earthquake forces.WHAT IS RISK?Risk is a measure of the expected losses (deaths, injuries, property, economic activity etc) due to ahazard of a particular magnitude occurring in a given area over a specific time period.“towardssaferINDIA”6
The figure onthe right illustrates essentially the fourfactors essentially hazards, location, exposure, andvulnerability which contribute to risk. They are:Hazards (physical effects generated in the naturallyoccurring event),Location of the hazards relative to the community atrisk,Exposure (the value and importance of the varioustypes of structures and lifeline systems such as watersupply, communication network, transportation networketc in the community serving the population, andVulnerability of the exposed structures and systems tothe hazards expected to affect them during their useful life.Risk reduction can take place in two ways:1. PreparednessThis protective process embraces measures which enable governments, communities and individuals to respondrapidly to disaster situations to cope with them effectively. Preparedness includes the formulation of viableemergency plans, the development of warning systems, the maintenance of inventories and the training ofpersonnel. It may also embrace search and rescue measures as well as evacuation plans for areas that may be atrisk from a recurring disaster.Preparedness therefore encompasses those measures taken before a disaster event which are aimed at minimisingloss of life, disruption of critical services, and damage when the disaster occurs. All preparedness planning needs tobe supported by appropriate legislation with clear allocation of responsibilities and budgetary provisions.2. MitigationMitigation embraces all measures taken to reduce both the effect of the hazard itself and the vulnerable conditionsto it in order to reduce the scale of a future disaster. Therefore mitigation activities can be focused on the hazarditself or the elements exposed to the threat. Examples of mitigation measures which are hazard specific includemodifying the occurrence of the hazard, e.g. water management in drought prone areas, avoiding the hazard bysiting people away from the hazard and by strengthening structures to reduce damage when a hazard occurs.In addition to these physical measures, mitigation should also be aimed at reducing the physical, economic andsocial vulnerability to threats and the underlying causes for this vulnerability.DISASTER MANAGEMENT CYCLEDisaster management can be defined as the body of policy and administrative decisions and operationalactivities which pertain to the various stages of a disaster at all levels. Broadly disaster management canbe divided into pre-disaster and post-disaster contexts. There are three key stages of activity that aretaken up within disaster management. They are:“towardssaferINDIA”7
1. Before a disaster strikesDISASTER MANAGEMENT(pre-disaster).ActivitiestakentoDISASTER RESPONSE (post-disaster)reduceEmergency Responsehuman and property lossescaused by the hazard andIndividualDisasterResponseResponse/ ReliefImmediate secureensure that these losses arealsominimizedwhentheyour safety and ofothers/rescue &provide firstaid/securesuppliesDISASTERSTRIKESdisaster strikes. Risk reductionactivities are taken under thisImmediate intervention.(Search & rescue, Security,Food, Water, Shelter &Sanitation, Clothes,Medical & trauma care)Duration: short-termPreparednessstage and they are termed asContingency Planning/Warningand Evacuation/consolidatepreparations for next disastersmitigation and preparednessactivities.RehabilitationRestoration of basicservices and functions.Duration: (weeks tomonths)Mitigation (RiskAssessment/Prevention)2. During a disaster (disasterHazard mapping/ Hazard andvulnerability assessment/structural and non-structuralmeasuresoccurrence).Activities taken to ensure thatthe needs and provisions ofReconstructionFull resumption ofservices, plus preventivemeasures. Duration:(months to years)Pre-disaster: risk reductionvictims are met and sufferingPost-disaster: recoveryDISASTER MITIGATION andDISASTER PREPAREDNESS (pre-disaster)is minimized. Activities takenunder this stage are called asemergencyresponseactivitiesReference: Are you Prepared? Learning from the Great Hanshin-Awaji Earthquake Disaster- Handbook for Disaster Reduction and Volunteer activities3. After a disaster (post-disaster)Activities taken to achieve early recovery and does not expose the earlier vulnerable conditions. Activitiestaken under this stage are called as response and recovery activities.PERSONAL AND COMMUNITY AWARENESSAs Indians we need to be aware of likely hazards and potential hazards, how, when and where they arelikely to occur, and the problems which may result of an event. With 60% of the land mass susceptible toseismic hazard damage (Moderate, High and Very High Zone); 40 million hectares (8%) of landmassprone to floods; 8000 Km long coastline with two cyclone seasons; 68% of the total area vulnerable todrought; Hilly regions vulnerable to avalanches/landslides/Hailstorms/cloudbursts; other Human causedhazards it is important most of all, we should be aware of how to cope with their effects.During the time of a disaster there will be delay before outside help arrives. At first, self-help is essentialand depends on a prepared community – that is a community which has:An alert, informed and actively aware populationA Preparedness and Response PlanAn active and involved local Government,Agreed, coordinated arrangements for response, preparedness and mitigation measures.“towardssaferINDIA”8
CHAPTER 2EARTHQUAKES HAZARDS AND DISASTERSANEARTHQUAKE –is a series ofunderground shockwaves and movementson the earth’s surfacecaused by naturalprocesses writhing theearths crust.ONSET TYPE AND WARNINGEarthquake is a sudden onset hazard. They occur at any time of year,day or night, with sudden impact and without any warning sign.Extensive research has been conducted in recent decades but there isno accepted method of earthquake prediction as on date.On January 26 2001 adevastatingearthquakeoccurred in the Kachchhdistrict of the state of Gujarat.The earthquake measured amagnitude of M6.9 on RichterScale. According to officialestimates, the total loss of lifewas 13,805 and 12, 05,198houses were damaged.ELEMENTS AT RISKSeveral key factors that contribute to vulnerability of human populations to earthquakes:Location of settlements in an earthquake prone area, especially on soft ground, on area prone tolandslides or along fault lines.Dense collection of weak buildings with high occupancy.Non-engineered buildings constructed by earth, rubble, buildings with heavy roofs (more vulnerablethan light weight structures), poor quality and maintenance of buildingsWeak or flexible storey intending for parking purposes.INDIAN EARTHQUAKESTotal Events: 3383MagnitudesM 5M 6M 7M 8“towardsThe Indian subcontinent lies upon the Indian Plate. Thisplate is moving northward at about 5 centimetres peryear and in doing so, collides with the Eurasian Plate.Upon the Eurasian Plate lie the Tibet plateau & CentralAsia. Due to this collision, the Himalayas are thrusthigher and very many earthquakes are generated in theprocess. This is the cause of earthquakes from theHimalayas to the Arakan Yoma.Figure to the left showing plot of Earthquakes (M 5.0) fromIMD Catalogue for the period from 1800 to Sept, 2001 (Totalevents 3383 events).9s a f e rI N D I A ”
List of some significant earthquakes in IndiaMagnitudeM 6MagnitudeM 6DateLocation8.01956 JUL 21ANJAR, GUJARAT7.07.51967 DEC 10KOYNA, MAHARASHTRA6.51885 MAY 30 SOPOR, J&K7.01975 JAN 19KINNAUR, HP6.21897 JUN 12SHILLONGPLATEAU8.71988 AUG 06MANIPUR-MYANMAR BORDER6.61905 APR 04KANGRA, H.P8.01988 AUG 21BIHAR-NEPAL BORDER6.41918 JUL 08SRIMANGAL, ASSAM7.61991 OCT 20UTTARKASHI, UP HILLS6.61930 JUL 02DHUBRI, ASSAM7.11993 SEP 306.31934JAN 15BIHAR-NEPALBORDER8.31997 MAY 22LATUR-OSMANABAD,MAHARASHTRAJABALPUR,MP1941 JUN 26ANDAMAN ISLANDS8.11999 MAR 29CHAMOLI DIST, UP6.81943 OCT 23 ASSAM7.22001 JAN 26BHUJ , GUJARAT6.91950 AUG 15 ARUNACHAL PRADESHCHINA BORDER8.5DateLocation1819 JUN 16KUTCH,GUJARAT1869 JAN 10NEAR CACHAR, ASSAM6.0Source: if.htmThe same process, results in earthquakes in the Andaman &Nicobar Islands. Sometimes earthquakes of different magnitudesoccur within the Indian Plate, in the peninsula and in adjoiningparts of the Arabian Sea or the Bay of Bengal. These arise due tolocalized systems of forces in the crust sometimes associated withancient geological structures such as in the Rann of Kachchh. Allearthquakes in peninsula India falls within this category.HAZARD ZONESAs per the latest seismiczoning map of India thecountry is divided intofour Seismic Zones.Zone V marked in redshows the area of VeryHigh Risk Zone, Zone IV Tectonic Map of India. Red lines showingmarked in orange shows active fault zones.the area of High Risk (Source: www.asc-india.org)Zone. Zone III marked inyellow shows the region of Moderate Risk Zone and Zone IImarked in blue shows the region of Low risk Zone. Zone V isthe most vulnerable to earthquakes, where historically some ofthe country's most powerful shock has occurred.Geographically this zone includes the Andaman & NicobarIslands, all of North-Eastern India, parts of north-western Bihar,eastern sections of Uttaranchal, the Kangra Valley in HimachalPradesh, near the Srinagar area in Jammu & Kashmir and theRann of Kutchh in Gujarat. Earthquakes with magnitudes inexcess of 7.0 have occurred in these areas, and have hadintensities higher than IX.Figure showing the Seismic Zones of India.The country is divided into four seismicZones – II, III, IV and V(Source: IS1893 (Part 1) : 2002)Much of India lies in Zone III, where a maximum intensity of VII can be expected. New Delhi lies in ZoneIV whereas Mumbai and Chennai lie in Zone III. All states and UTs across the country have experiencedearthquakes.“towardssaferINDIA”10
Measuring the Size of an Earthquake - MSK 64 Intensity ScaleIntensity is a qualitative measure of the actual shaking at a location during an earthquake, and is notated in a roman capitalnumeral. The MSK (Medvedev, Sponheuer and Karnik) scale is more convenient for application in field and is widely used inIndia. The zoning criterion of the map is based on likely intensity. The scale range from I (least perceptive) to XII (most severe).The intensity scales are bas ed on three features of shaking – perception by people, performance o f buildings, and changes tonatural surroundings.The seismic zoning map broadly classifies India into zones where one can expect earthquake shaking of the more or less thesame maximum intensity. The shaking intensity associated with different zones is shown in the table below:ZoneArea liableto shakingintensityIIVI (andlower)IIIVIIIVVIIIVIX (andhigher)Description(Arrangement in paragraphs of scale as follows: i) Persons and surroundings, ii) Structures of allkinds, iii) Nature)VI Frighteningi) Felt by most indoors and outdoors. Many people in buildings are frightened and run outdoors. Afew persons loose their balance. Domestic animals rum out of their stalls.In many instances, dishes and glassware may break, and books fall down, pictures move, andunstable objects overturn. Heavy furniture may possibly move and small steeple bells may ring.ii) Damage of Grade 1*** is sustained in single** buildings of Type B* and in many** of Type A*.Damage in some buildings of Type A is of Grade 2***.iii) Cracks up to widths of 1cm possible in wet ground; in mountains occasional landslips: change inflow of springs and in level of well water are observed.VII Damage of Buildingsi) Most people are frightened and run outdoors. Many find it difficult to stand. The vibration is noticedby persons driving motor cars. Large bells ring.ii) In many buildings of Type C* damage of Grade 1 is caused; in many buildings of Type B damageis of Grade 2. Most** buildings of Type A suffer damage of Grade 3***, few of Grade 4***. In singleinstances, landslides of roadway on steep slopes: crack in roads; seams of pipelines damaged;cracks in stone walls.iii) Waves are formed on water, and is made turbid by mud stirred up. Water levels in wells change,and the flow of springs changes. Some times dry springs have their flow resorted and existingsprings stop flowing. In isolated instances parts of sand and gravelly banks slip off.VIII Destruction of buildingsi) Fright and panic; also persons driving motor cars are disturbed, Here and there branches of treesbreak off. Even heavy furniture moves and partly overturns. Hanging lamps are damaged in part.ii) Most buildings of Type C suffer damage of Grade 2, and few of Grade 3, Most buildings of Type Bsuffer damage of Grade 3. Most buildings of Type A suffer damage of Grade 4. Occasional breakingof pipe seams. Memorials and monuments move and twist. Tombstones overturn. Stone wallscollapse.iii) Small landslips in hollows and on banked roads on steep slopes; cracks in ground up to widths ofseveral centimeters. Water in lakes becomes turbid. New reservoirs come into existence. Dry wellsrefill and existingIX General damage of buildingsi) General panic; considerable damage to furniture. Animals run to and fro in confusion, and cry.ii) Many buildings of Type C suffer damage of Grade 3, and a few of Grade 4. Many buildings of TypeB show a damage of Grade 4 and a few of Grade 5. Many buildings of Type A suffer damage ofGrade 5. Monuments and columns fall. Considerable damage to reservoirs; underground pipes partlybroken. In individual cases, railway lines are bent and roadway damaged.iii) On flat land overflow of water, sand and mud is often observed. Ground cracks to widths of up to10 cm, on slopes and river banks more than 10 cm. Further more, a large number of slight cracks inground; falls of rock, many land slides and earth flows; large waves in water. Dry wells renew theirflow and existing wells dry up.X General Destruction of BuildingsXI DestructionXII Landscape ChangesNote: Fore more information on MSK 64 Intensity Scale refer Indian Seismic Code IS 1893 (Part 1)*a) Type of Structures (Buildings)Type A - Building in field-stone, rural structures, unburnt-brick houses, clay houses.Type B - Ordinary brick buildings, buildings of large block and prefabricated type, half timbered structures, buildings in natural hewn stone.Type C - Reinforced buildings, well built wooden structures.**b) Definition of QuantitySingleManyMostFew - About 5 percentAbout 50 percentAbout 75 percent*** Classification of Damage to buildingsGrade 1Slight damageFine cracks in plaster; fall of small pieces of plasterGrade 2ModerateSmall cracks in walls; fall of fairly larger pieces of plaster; pantiles slip off; cracks in chimneys parts ofdamagechimney fall down.Grade 3Heavy damageLarge and deep cracks in walls; fall of chimneys.Grade 4DestructionGaps in walls; parts of buildings may collapse; separate parts of the buildings lose their cohesion; and innerwalls collapse.Grade 5Total damageTotal collapse of the buildings“towardssaferINDIA”11
TYPICAL EFFECTSPhysical Damage – damage or loss of buildings and service structures. Fires, floods due to dam failures,landslides could occur.Casualties – often high, near to the epicenter and in places where the population density is high (say,multistoried buildings) and structures are not resistant to earthquake forces.Improperly designed weak or flexible storey leads to poorperformance duringearthquakes. Many buildings with openground storeys intended for parking collapsed in the Bhujearthquake. Seen is the picture is a vertical split of a building dueto collapse of a partially open ground storey building.Partial collapse of non engineered building (stonemasonry walls) during 1991 Uttarkashi earthquake.(Source: Earthquake Tips IITK-BMTPC)(Source www.nicee.org Earthquake Tips IITK-BMTPC)Public health – multiple fracture injuries, moderately and severely injured is the most widespreadproblem, breakdown in sanitary conditions and large number of casualties could lead to epidemics.Water supply – severe problems due to failure of the water supply distribution network and storagereservoirs. Fire hydrants supply lines if vulnerable could hamper fire service operations.Transport network – severely affected due to failure of roads and bridges, railway tracks, failure of airportrunways and related infrastructure.Electricity and Communication – all links affected. Transmission towers, transponders, transformerscollapse.MAIN MITIGATION STRATEGIESEngineered structures (designed and built) to withstand ground shaking. Architectural and engineeringinputs put together to improve building design and construction practice. Analyze soil type beforeconstruction and do not build structures on soft soil. To accommodate on weak soils adopt safetymeasures in design. Note: Buildings built on soft soils are more likely to get damaged even if theearthquake is not particularly strong in magnitude. Similar problem persists in the alluvial plains andconditions across the river banks. Heavy damages are concentrated when ground is soft.Good soil conditions– sharp rumblingWeak soil conditions– violent shakingHypocenterEssential requirements in a Masonry buildingEffect of soil type on ground shaking“towardssaferINDIA”12
Follow Indian Standard Codes for construction of buildings.Enforcement of the Byelaws including Land use control and restrictionon density and heights of buildingsStrengthening of important lifeline buildings which need to befunctional after a disaster. Upgrade level of safety of hospital, fireservice buildings etc.Public awareness, sensitization and training programmes forArchitects, Builders, Contractors, Designers, Engineers, Financiers,Government functionaries, House owners, Masons etc.Reduce possible damages from secondary effects such as like fire,floods, landslides etc. e.g. identify potential landslide sites and restrictconstruction in those areas.IS 1893 (Part 1):2002Indian StandardCriteria for Earthquake ResistantDesign of StructuresPart 1 General Provisions and Buildings(Fifth revision)Bureau of Indian StandardsCOMMUNITY BASED MITIGATIONJune 2002Community preparedness along with public education is vital formitigating the earthquake impact. Earthquake drills and Public This Indian Standard isawareness programme.adopted by Bureau of IndianCommunity based Earthquake Risk Management Project should be Standards and it givesdeveloped and sustainable programmes launched. Retrofitting of recommendations for designschools and important buildings, purchase of emergency response criteria of structures.equipment and facilities, establishing proper insurance can be theprogrammes under Earthquake Risk Management Project. A large number of local masons andengineers will be trained in disaster resistant construction techniques. A large number of masons,engineers and architects can get trained in this process.Retrofitting of School Buildingof Ahmedabad MunicipalCorporation.This building was partlydamagedduringtheearthquake. The school wasretrofitted and is functioning.WEB RESOURCES:www.nicee.org: Website of The National Information Center of Earthquake Engineering (NICEE) hosted at Indian Institute ofTechnology Kanpur (IITK) is intended to collect and maintain information resources on Earthquake Engineering and makethese available to the interested professionals, researchers, academicians and others with a view to mitigate earthquakedisasters in India. The host also gives IITK-BMTPC Earthquake e.htm Earthquake Information – India Meteorological Department, India. IMDdetects and locates earthquakes and evaluates seismicity in different parts of the country.www.bmtpc.org In order to bridge the gap between research and development and large scale application of new buildingmaterial technologies, the erstwhile Ministry of Urban Development, Government of India, had established the BuildingMaterials And Technology Promotion Council in July heEarth,itsnaturalandliving resources, natural hazards, and the environment.www.neic.cr.usgs.gov National Earthquake Information Center (NEIC) - World Data Center for Seismology Earthquakeinformation and observation station: The site hosts one of the most comprehensive systems.www.quake.wr.usgs.gov Earthquake Reporting Service: U.S. Geological Survey and UC Berkeley service for earthquakereporting. Earthquake basics and educational material; geological and historical information; links to professional andamateur organizations; online access to earthquake data. Current research activities and results in seismology, crystalstructure and deformation, geology and borehole physics. for morewww.asc-india.org Amateur Seismic Centre is a comprehensive website carrying details of state wise seismicty for thecountry. This also has extensive reports on various past earthquakes with rare photographs and maps.“towardssaferINDIA”13
CHAPTER 3TSUNAMI HAZARDS AND DISASTERSTSUNAMI –is a Japanese wordmeaning“harbourwave”. These waves,whichoftenaffectdistantshores,originate from underseaorcoastalseismicactivity, landslides, andvolcanic eruptions.Whatever the cause,sea water is displacedwith a violent motionandswellsup,ultimately surging overlandwithgreatdestructive power.ONSET TYPE and CAUSESIf the earthquake or under water land movement is near the coast thentsunami may strike suddenly and if the earth movement is far in the seathen it may take few minutes to hours before striking the coast. The onset isextensive and often very destructive. The general causes of Tsunamis aregeological movements. It is produced in three major ways. The mostcommon of these is fault movement on the sea floor, accompanied by anearthquake. To say that an earthquake causes a tsunami is notcompletely correct. Rather, both earthquakes and tsunamis result from faultmovements. Probably the second most common cause of tsunamis is alandslide either occurring underwater or originating above the sea andthen plunging into the water. The third major cause of tsunamis isvolcanic activity. The flank of a volcano, located near the shore orunderwater, may be uplifted or depressed similar to the action of a fault.Or, the volcano may actually explode. In 1883, the violent explosion ofthe famous volcano, Krakatoa in Indonesia, produced tsunamismeasuring 40 meters which crashed upon Java and Sumatra. over 36,000people lost their lives as a result of tsunami waves from Krakatoa. Thegiant tsunamis that are capable of crossing oceans are nearly always“towardssaferIND26th December, 2004, AmassiveearthquakeofMagnitude 9.0 hit Indonessiagenerating Tsunami waves inSouth-east Asia & easterncoast of India. Height oftsunami waves ranged from 3– 10 m affecting a totalcoastal length of 2260 km intheStatesofAndhraPradesh, Tamil Nadu, Kerala& UTs of Pondicherry,Andaman & Nicobar Islands.Tsunami waves travelledupto a depth of 3 km from thecoast killing more than10,000 people & affectedmore than lakh of housesleaving behind a huge trail ofdestruction.IA”14
created by movement of the sea floor associated withearthquakes which occur beneath the sea floor or near theocean.WARNINGTsunami is not a single giant wave. It consists of ten ormore waves which is termed as a “tsunami wave train”.Since scientists cannot predict when earthquakes willoccur, they cannot predict exactly when a tsunami will begenerated. Studies of past historical tsunamis indicatewhere tsunamis are most likely to be generated, theirpotential heights, and flooding limits at specific coastallocations. With use of satellite technology it is possible toprovide nearly immediate warnings of potentiallytsunamigenic earthquakes. Warning time depends uponthe distance of the epicenter from the coast line. Thewarning includes predicted times at selected coastalcommunities where the tsunami cold travel in a few hours.In case of tsunamigenic earthquakes or any othergeological activity people near to the coastal areas mayget very little time to evacuate on receiving of warning.Tsunami wave train formation: Seen in the figure isthe rupture in the seafloor shunted in the verticaldirection. This movement displaces hundreds ofcubic kilometres of the overlaying water, generatinga massive tsunami, or sea surge.Note: Ground shaking signals the occurrence of the earthquake. It is important to move away from the coastal areassince a tsunami may accompany the earthquake.ELEMENTS AT R
Disaster management can be defined as the body of policy and administrative decisions and operational activities which pertain to the various stages of a disaster at all levels. Broadly disaster management can be divided into pre-disaster and post-disaster contexts. There are three key stages of activity that are taken up within disaster .
1.8 Disasters, Risk Reduction and Management - Definitions 6 1.8.1 Disasters 7 1.8.2 Disaster Management 7 1.8.3 Disaster Risk Reduction (Mitigation) 8 1.9 Types of Disasters 8 1.9.1 Natural Hazards 8 1.9.2 Human-Induced Disasters 10 1.10 Levels of Disasters 11 1.11 Institutional Framework 11 1.11.1 National Level 11
perception of natural disasters and hazards. Previously, hazards and disasters were seen as two closely associated and interrelated phenomena, i.e. areas prone to natural hazards, were more vulnerable to disasters. Hence, people avoided tampering with the delicate balance that existed in a given ecosystem. People avoided intensification of
Manmade Disasters - An Overview We have so far discussed possible disasters that can result from natural hazards. We have also seen how human actions in some cases aggravate the disastrous effects of natural hazards. For instance, improper constructions can increase vulnerabilities to ea
Natural Hazards 1.1 Engage Natural Hazards Western Australia experiences a range of natural hazards each year, which include bushfire, severe storms, floods, cyclones, earthquake and possibly tsunami. These are called natural hazards because they are elements of nature that can be extreme and dangerous. These hazards (apart from some
hazards and disasters. . South Africa faces increasing levels of disaster risk. It is exposed to a wide range of weather hazards, including drought, cyclones and severe storms that can trigger . Similarly, our shared borders with six southern African neighbours present both natural and human-induced cross-boundary risks, as well as .
The number of people affected by natural disasters around the world is rising. Over the past two years, 700 natural disasters were registered worldwide affecting more than 450 million . are especially at risk. While natural disasters cannot be prevented, much can be done to reduce their human and economic costs.
Introduction to Human Populations, Natural Hazards and Disasters Lectures: Introduction to human populations and the associated impacts of natural hazards. Discussion: Discussions Sections do not meet No deliverables. Week 2 1/21 1/23* Monday 1/20 is a University Holiday Human Populations Lectures: Human life, natural hazards, risk,
Flood hazards assessment on riparian zones in the hinterland to investigate food security impacts Flood modelling and prediction Coastal erosion modelling To encourage data gathering, preparation of hazards/ risk maps and sensitization on natural hazards Inform national policies on hazards prevention & management The Way Forward
