What is an environmental (natural) hazard?

Authors Avatar

Collette Reynolds

___________________________________________________________________

Assignment 1

Environmental Hazards

and their Effects

Collette Reynolds

(Access to Teaching)

___________________________________________________________________

What is an environmental (natural) hazard?

Environmental or natural hazards result from natural processes within the environment and they have the potential to affect people and property.  These include:

  • Earthquakes
  • Volcanic eruption
  • Droughts
  • Floods
  • Severe weather e.g. hurricanes, tornadoes, etc..

The hazard event causes the actual damage to people and/or property.  An environmental (natural) hazard only becomes a disaster when it affects people, hitting communities and disrupting normal, daily functioning.  This causes deaths, physical damage to buildings and infrastructure, and long-term economic damage.

Environmental hazards can be put into 3 main groups:

  • Climatic e.g. droughts, floods, heatwaves, hurricanes, tornadoes, etc.
  • Geomorphic e.g. earthquakes, volcanic eruptions, tsunamis, landslides, etc.
  • Biological – faunal and floral e.g. plant diseases, infestations, poisonous species, etc.

In this assignment I will be concentrating on environmental hazards that relate to tectonic processes.  Hazard events such as earthquakes and volcanic eruptions are particularly problematic.

What causes earthquakes and volcanic hazards?

Earthquakes and volcanoes are caused by tectonic processes.  Tectonic processes have created major features such as mountain chains, volcanoes, ocean trenches, and so on.

The Theory of Plate Tectonics is the study of the movement of tectonic plates and the landforms that are created by this plate movement.

(put these ideas into sentences)

  • The Earth’s structure consists of three major zones – the core, mantle and crust
  • The Earth’s crust is divided into a number of plates (large and small)
  • These rigid plates float on the semi-molten mantle
  • Plate movement could be caused for a number of reasons
  • The most commonly stated theory is that it is caused by large convection currents inside the Earth’s mantle
  • Crust is continually being created and destroyed so the Earth remains roughly the same size
  • According to the theory of plate tectonics, new plate material is created where plates move apart, whilst old (existing) plate material is destroyed where plates collide – in the centre of the rigid plates it is very stable and there is little activity here
  • Plates move in one of three directions – towards each other (convergent), away from each other (divergent) or past each other (conservative)
  • Earthquakes are commonly found at convergent and conservative plate boundaries
  • Volcanoes are commonly found at divergent plate boundaries
  • A lot of important work has developed from earlier ideas put forward by Alfred Wegener in his Theory of Continental Drift (1912)
  • He suggested that at one time all the continents had been joined together but they had gradually split up
  • More scientific research in the 1950s and 1960s, such as looking at rock magnetism, confirmed his ideas
Join now!

What threats do environmental hazards pose?

Environmental hazards pose a number of threats to humans and the environment, some relatively minor but others very severe.  Different types of hazard pose different threats and have different impacts.  A threat may be an event that occurs quite often e.g. hurricanes or tornadoes, or an event that is less frequent but carries much more force e.g. an earthquake.

The main threats that most environmental hazards pose include deaths and destruction caused by the hazard events, and the economic cost to overcome the disasters.

What effects do environmental ...

This is a preview of the whole essay