Specific hazards and mitigation

Specific hazards and mitigationDone by-suhaib

Introduction to Natural Hazards What is a “Geohazard”?

• Earth processes (involving the lithosphere, hydrosphere & atmosphere) that, upon interaction with human activity, cause loss of life and property

It is important to understand the human element without it, there would be no hazard because of it, the science of geohazards becomes more

important every year mitigation: reduction/prevention

Why is the human element so critical?

The Earth’s population is increasing more people living in hazard-prone areas populations are becoming hyper-concentrated consumption of resources examples: 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 coastal prone to severe storm and tsunami damage

and a large majority lie in areas subject to other geohazards (for example volcanoes and earthquakes)

• Therefore, we must try to reduce (mitigate) the hazards through:

• scientific study• population education• changes in engineering/building practices• management plans and hazard response scenarios

Types of Natural Hazards Volcanoes, floods, earthquakes, tornadoes,

tsunamis, etc.• can act adversely on human processes• can occur: without warning (e.g. earthquakes) with warnings (precursors) (e.g. satellite monitoring of cyclone tracks, or the presence of ground deformation at a volcano before an eruption)

To help mitigate the hazard we need to know: Frequency vs. Magnitude

• F: how often a given event occurs in a certain region

• M: how powerful (amount of energy released) an event is for example, high M hazards happen with low F, but are much more destructive

Scope• S: area affected by a given hazard local: landslides, floods, earthquakes, fire … regional: tsunamis, volcanoes, larger earthquakes, cyclones …

global: large volcanoes, global warming, meteorite impacts …

How do we mitigate the hazard from tsunamis?

Monitoring• process is very technology-intensive high costs for many poorer countries

• often no technology available to monitor local tsunamis for example, Papua New Guinea has no monitoring stations reliant on the Pacific Tsunami Warning Center

tsunami in 1998 was not detected


Building restrictions in hazard prone areas • In Hawaii, Hilo harbor and downtown was

destroyed by the tsunamis of 1946 and 1960

• The town is now rebuilt on higher ground and the devastated area is a park


Seawall construction • cause early wave breaking• prevent wave run up into urban areas


Education• warning systems• evacuation plans• general understanding of the hazards

involved

How do we mitigate the hazard from a cyclone?

Monitoring• early warning systems

Infrastructure• cyclone walls• communal shelters

Education and planning

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