Презентація на тему «Natural Hazards»

content: Presentation: “Natural Hazards”Prepared byOleksandra Pekhn'oForm 11-ASchool of Chynadiievo

content: Introduction to Natural HazardsWhat is a “Geohazard”?Earth processes (involving the lithosphere, hydrosphere & atmosphere) that, upon interaction with human activity, cause loss of life and propertyIt is important to understand the human elementwithout it, there would be no hazardbecause of it, the science of geohazards becomes more important every yearmitigation: reduction/preventiongeo-processhumanprocessHazardousconditionor result

content: The Earth's population is increasingmore people living in hazard-prone areaspopulations are becoming hyper-concentratedconsumption of resourcesexamples:today there are 6 billion people on Earth ( ~ 50% live in cities)by 2025, there will be ~8 billion people (~ 66% in cities)of these cities, 40% are coastalprone to severe storm and tsunami damageand a large majority lie in areas subject to other geohazards (for example volcanoes and earthquakes)Why is the human element so critical?

content: The Earth's population is increasingmore people living in hazard-prone areaspopulations are becoming hyper-concentratedconsumption of resourcesexamples:today there are 6 billion people on Earth ( ~ 50% live in cities)by 2025, there will be ~8 billion people (~ 66% in cities)of these cities, 40% are coastalprone to severe storm and tsunami damageand a large majority lie in areas subject to other geohazards (for example volcanoes and earthquakes)Why is the human element so critical?

content: CANNOT stop the geologic processesCANNOT stop the population growth/expansionTherefore, we must try to reduce (mitigate) the hazards through:scientific studypopulation educationchanges in engineering/building practicesmanagement plans and hazard response scenarios

content: Earthquakes and Tsunamis

content: San Francisco - Great EarthquakeMagnitude 7.7 - 8.3

content: Earthquake HazardsThese are important hazards to understand:the natural hazard that on average kills the highest number of people per year (> 1 million during the past century)commonly strikes without warningno time for evacuationnot a predictable trend to earthquake numbers, magnitude or location1000's of large earthquakes every year~ 20 are > M7.0 and these account for 90% of the energy released and 80% of all the fatalities

content: Earthquake HazardsThese are important hazards to understand:the natural hazard that on average kills the highest number of people per year (> 1 million during the past century)commonly strikes without warningno time for evacuationnot a predictable trend to earthquake numbers, magnitude or location1000's of large earthquakes every year~ 20 are > M7.0 and these account for 90% of the energy released and 80% of all the fatalities

content: How do we mitigate the hazard from earthquakes?Reinforce buildingsEducationDisaster plan

content: Earthquakes and Tsunami'sAn earthquake under the ocean has the potential to form a tsunami.The earthquake must vertically displace overlying water (extensional or compressional faults - not transform)ExtensionCompressionTransform

content: How does an earthquake form a tsunami?

content: 2004 South Asian Boxing Day eventBiggest earthquake in 40 years!Magnitude 9.2150 km off the west of Northern SumatraGenerated a disastrous tsunami in 12 countries

content: The earthquake occurred at a convergent tectonic plate boundary (subduction zone)An estimated 1,600 km (994 miles) of faultline slipped about 15 m (50 ft)!The earthquake released 20 x 1017 Joules of energyEquivalent to:475,000,000 kg of TNT23,000 Hiroshima atomic bombs!Second largest recorded earthquake

content: A village near the coast of Sumatra lays in ruin after the tsunami.

content: How do we mitigate the hazard from tsunamis?Monitoringprocess is very technology-intensivehigh costs for many poorer countriesoften no technology available to monitor local tsunamisfor example,Papua New Guinea has no monitoring stationsreliant on the Pacific Tsunami Warning Centertsunami in 1998 was not detected

content: Seawall constructioncause early wave breakingprevent wave run up into urban areasHow do we mitigate the hazard from tsunamis?

content: Educationwarning systemsevacuation plansgeneral understanding of the hazards involvedPunishmentFrom God45%Natural event35%Bomb 20%Population reaction: Papua New Guinea (1998)How do we mitigate the hazard from tsunamis?

content: Tropical Storms

content: Same Storm - Different Name

content: Most widespread destructive weather hazardFor example: Hurricane Floyd (1999)only a moderate level hurricanecaused US$5.6 billion in damage in the Bahamas and North Carolina (USA) and 57 fatalitiesTropical Cyclones(Left) Three different cyclones spinning over the western Pacific Ocean on August 7, 2006.

content: How do cyclones form?The above figure shows how cyclones form. The green arrows show where warm air is rising. The red arrows indicate where cool air is sinking.

content: Cyclone CategoriesCategoryWind Speed (mph)Damage at LandfallStorm Surge (feet)174-95Minimal4-5296-110Moderate6-83111-130Extensive9-124131-155Extreme13-185> 155Catastrophic19+The Saffir-Simpson Hurricane Scale

content: Hurricane KatrinaHurricane Katrina was the most costly and most deadly hurricane in the history of the USA.Category 5At least 1,836 fatalitiesDamage estimated at US$ 81.2 billion

content: Hurricane Katrina

content: What damage is produced?Storm Surgewater that is pushed toward the shore by the force of the cyclone winds.

content: What damage is produced?Windresponsible for the loss of power and utilitieswind damage affects larger areas than surgeflying debristree loss

content: What damage is produced?Flying debrisdebris propelled at high speeds

content: How do we mitigate the hazard from a cyclone?Monitoringearly warning systemsInfrastructurecyclone wallscommunal sheltersEducation and planning

content: Natural Hazards SummaryGraph showing the number of deaths per year due to natural hazard events