creater suhaib mohammed 9-a

1. Done by-suhaib

2.  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

3.  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)

4. • 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

5.  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)

6.  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 …

7.  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

8. 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

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

10. Education
• warning systems
• evacuation plans
• general understanding of the hazards involved

11. Monitoring
• early warning systems
Infrastructure
• cyclone walls
• communal shelters
Education and planning

12. Thanks for watching