Geologic Forces of Nature

Geologic processes, are natural and play a fundamental role in shaping ecosystems.

 

Abandoned Mine Hazards

Avalanche

Coastal Geohazards

Glacial Outburst Floods—Jökulhlaups

Landslide Hazards—Mass Wasting

Seismic Activity—Earthquakes

Sinkholes and Subsidence

Volcanic Hazards

 

Sinkholes and Subsidence

The normal processes of landscape development in karstic areas may include localized, and seemingly spontaneous, subsidence. In populated areas, sinkholes can be destructive to facilities and potentially life threatening. Most observed collapses occur in soils and sediments overlying karstic bedrock.

Sinkhole collapses occur naturally, but they can also be induced by human activities. Induced sinkholes generally develop much faster than natural sinkholes. Urbanization increases the risk of induced sinkhole collapse.

The risk of collapse may increase because of changes in land use, stream bed diversions, and impoundments that locally increase the downward movement of water into bedrock openings beneath soil; also greater frequency and magnitude of water-table fluctuations caused by urban groundwater withdrawal and injection (Veni et al. 2001).

 

Volcanic Hazards

An unpredictable nature mixed with an ability to release massive amounts of energy make volcanoes extremely hazardous. The types of hazards that threaten an area will vary based on the type of volcano. Some hazards are local in scale, while others can affect the entire planet.

Some of the major hazards of volcanic eruptions:

• Blowdown
• Lahar
• Lava flow
• Pyroclastic flow
• Tephra
• Tsunami
• Volcanic gas

Volcanic hazards assessment
In populated areas around active volcanoes, it is important to know what to expect in the event of an eruption. Scientists work hard to develop modeling techniques that can predict the hazards resulting from volcanic activity.

From monitoring data, it is possible to make predictions of what type of eruption will occur and where on the volcano it will occur. Also, the local geology allows models to predict where lava flows and lahars could be directed.

There is no absolute certainty in predictions, but they can save lives if enough time is given for people to evacuate or take proper protective measures.

Maps are extremely useful to scientists who wish to predict the impacts and hazards of volcanic activity. Geographic Information Systems (GIS) can help create models that map the areas of greatest danger or impact for hazards such as ashfall, pyroclastic flows, blowdown, debris avalanches, and lahars.