Earth processes such as volcanic eruptions, floods, landslides, and glaciers leave behind evidence of their passing in the form of layers known as deposits. By studying deposits of recent geologic events, geologists are able to better understand older deposits and identify the processes that caused them.
Soil is often overlooked as a natural resource. Like fossil fuels, we depend on it for energy in the form of foods. And, like fossil fuels, it is nonrenewable. Soil is a delicate balance of inorganic minerals, organic matter, living organisms, soil water, and soil atmosphere. The natural development of soil is an exceedingly slow process. In a few hours, a heavy rain falling on exposed soil can remove inches of what took hundreds of years to form. Here is a simple exercise that will allow you to compare the rates and amounts of erosion that result from various land uses.
The Gravestone Project, part of the global citizen science program called EarthTrek (www.goearthtrek.com), is seeking volunteers to visit cemeteries around the world and collect scientific data on how marble gravestones are weathering.
Landslides not only are dangerous — causing on average more than 25 deaths and over $1 billion in damages a year — but are also widespread, occurring in all 50 states. Compounding the hazards, these natural disasters often occur along with other similar natural phenomena, such as floods or earthquakes. To minimize risk, the slope of land and materials underground must be considered when planning how to build in a community. Altering the slope of land, or even the amount of vegetation on a slope, can have dangerous consequences.