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USGS · fs20073030

Geographic Analysis and Monitoring Program

Abstract

The surface of the Earth is changing rapidly, at local, regional, national, and global scales, with significant repercussions for people, the economy, and the environment. Some changes have natural causes, such as wildland fires or hurricanes, while other changes on the land, such as resource extraction, agricultural practices, and urban growth, are human-induced processes. There are other types of changes that are a combination of natural and human-induced factors; landslides and floods, for example, are fundamentally natural processes that are often intensified or accelerated by human land use practices. Whatever their cause, land-surface changes can have profound environmental and economic impacts.

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Jon C. Campbell. 2007. Geographic Analysis and Monitoring Program. https://doi.org/10.3133/fs20073030

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Divisions of geologic time—Major chronostratigraphic and geochronologic units

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