This document discusses geohazards and how the increasing human population is exacerbating their effects. It defines a geohazard as an earth process involving the lithosphere, hydrosphere, and atmosphere that causes loss of life and property through interaction with human activity. The document notes that the world's population is growing and becoming more urbanized, putting more people in areas prone to hazards like coastal storms, tsunamis, earthquakes, and volcanoes. To reduce the impact of geohazards, the document advocates scientific study, education, engineering changes, and hazard response planning. It also discusses monitoring hazards, building restrictions in hazard-prone areas, seawall construction, and education as important mitigation strategies

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