Geohazards

1. General 
   1. Definition

      Natural hazards are naturally occurring physical phenomena having atmospheric, geologic or hydrologic origin.  The geological hazards are natural phenomena but they can also be man-made. They are, generally, the result of adverse geologic or hydrologic conditions capable of causing damage or loss of property and life. Worldwide, these hazards threaten lives and properties, and causing deaths and billions of dollars in damage every year. 

   2. Types of Geological Hazards 

      The geologic hazards are the result of either Internal Geological Processes (1) or External Geological Processes. The hazards that are caused by internal geological processes include earthquakes, volcanicity and tsunamis. The hazards that are the result of external geological processes, on the other hand include, floods, mass wasting (landslides, mudslides, debris flows and rock falls), subsidence, earth fissures, sand hazards (drifting sand, sand dunes migration and sand storms), diaperic features (salt domes), problematic soils (swelling soil, collapsing soil and sabkha soil), weak rocks, beach erosion, global warming and seawater level rising, and radioactivity. 

2. Geological Hazards in Saudi Arabia

1. Types of Man-made Hazards 

   Some of the above mentioned geological hazards can also be man-made. Examples of these hazards include, floods caused either by dam failure or urbanization, earth fissures caused by excessive groundwater pumping, sand hazards caused by human activities and errors in planning, landslides and rock falls along road cuts, groundwater level rise in cities and urban areas, and soil and water pollution. 

1.  Health Hazards 

   Some of these hazards also have adverse effects on human health. Examples of these hazards include the effect of soil chemistry on the food supply, indoor radon, asbestos and lead mining operations and radioactivity in drinking water. 

The Tectonics of the Arabian Plate including Zagros Mountains Tectonics and Red Sea Tectonics partly explains the cause of many geological hazards. The Kingdom’s existing arid weather conditions with high temperature spills, occasional torrential rain storms and high speed wind gusts are also the cause of some other geologic and hydrologic hazards. 

The following is a simplified map showing the major geological hazards in the Kingdom (2, 3). The details of these hazards and other potential hazards will be shown by pressing the respective cyber link. 

1. Hazards as Result of Internal Geological Processes 
   1. Earthquake Hazards
   2. Volcanic Hazards
   3. Tsunami Hazards 
2. Hazards as Result of External Geological Processes 
   1. Flood Hazards
   2. Mass Wasting Hazards (Landslides, rock falls and debris flows)
   3. Subsidence Hazards
   4. Earth Fissures Hazards
   5. Sand Hazards (drifting sand, sand dunes migration and sand storms)
   6. Salt Domes Hazards
   7. Problem Soils Hazards(swelling soil, collapsing soil and sabkha soil)
   8. Weak Rocks Hazards
   9. Radioactivity Hazards
   10. Air, Water and Soil Pollution Hazards
   11. Groundwater Level Rise Hazards 
3. Potential Hazards that Need to be Investigated 
   1. Beach Erosion Hazards
   2. Global Warming and Seawater Level Rising Hazards
   3. Desertification Hazards 
4. Adverse Health Conditions 
   1. Effect of Soil Chemistry on the Food Supply
   2. Indoor Radon Hazards
   3. Impact of Industrial and Mining Operations on Human Health 

1. The Required Man Power 

   The geological hazards vary in type, in intensity and in location with respect to populated areas. The man power needed to identify, to study and to mitigate the hazards around the cities and the towns are the Civil Defense personnel, in cooperation with qualified geologists and engineers from the scientific organizations in the Kingdom. Each will have his role(s) to perform: 

   1. Role of Geologist or Engineer
   2. Roles of Civil Defense Personnel

Protective Plan

Emergency Plan

Mitigation Plan

Frequently published information circulars and hazard prevention or avoidance guides are envisaged and will be referred to in future in this website.  

1. http://msewilliams.cmswiki.wikispaces.net/file/view/Chapter%2014.pdf/448613710/Chapter%2014.pdf

1. http://www.slideshare.net/WilliamShehata/newsfeed

1. http://www.cabrillo.edu/~dschwartz/documents/ES10_Geol_Proc_Hazards_Fall12.pdf