Seismic Exploration

Seismic surveys first came on the scene in the 1980s. Companies in the petroleum industry use seismic technology to locate oil and natural gas deposits. Seismic exploration involves mapping the sub-surface geology using sound waves generated from special equipment. This equipment, usually mounted on trucks, is carried across the landscape along straight lines and readings are taken at measured intervals. Often a series of parallel lines of vegetation is cleared to allow seismic exploration, leaving long, narrow cutlines, called seismic lines. These lines are often maintained for many years for further seismic exploration or general access by other forest users, but eventually they are reclaimed or naturally reforested.

Every year, a great deal of seismic activity occurs throughout Alberta, on both public and private lands. The amount of seismic activity varies greatly from year to year, depending on the energy market and other factors. During the early 1990s, 341,288 kilometres were covered by seismic exploration. Just over two-thirds (67.2 percent) of this activity occurred in the settled part of the province. 

Exploration companies often take advantage of existing cutlines for their seismic activity. During the 1990–1994 period, about 45 percent of the exploration on public lands used existing cutlines. Although this reduces the number of new seismic lines that must be cut, it delays the eventual reforestation of existing lines as they continue to be used.

Department of the Environment. State of the Environment Report, Terrestrial Ecosystems. Edmonton: n.p., 2001. With permission from Alberta Environment.