LANDSLIDES IN THE GREATER PITTSBURGH REGION, PENNSYLVANIA.

THE GREATER PITTSBURGH REGION, WHICH IS WITHIN THE APPALACHIAN PLATEAUS PHYSIOGRAPHIC PROVINCE AND WHICH IS UNDERLAIN MOSTLY BY NEARLY HORIZONTAL CYCLOTHEMIC PENNSYLVANIAN TO PERMIAN ROCKS, IS IN AN AREA THAT HAS A HIGH POTENTIAL FOR LANDSLIDING. MORE THAN 3,000 RECENT AND AT LEAST 12,000 OLDER SLIDES WERE RECOGNIZED IN ALLEGHENY AND WASHINGTON COUNTIES ALONE. THIS REPORT INCORPORATES DISCUSSIONS RELATED TO MASS-MOVEMENT TYPES, SELECTED LANDSLIDE LOCALITIES, AND RECOGNITION OF MASS-MOVEMENT FORMS AND POTENTIALLY UNSTABLE SLOPES ON AERIAL PHOTOGRAPHS OF THE REGION.