Geology topics

Christopher Stohr

Publications and source records attributed to Christopher Stohr.

3 recordsLinked to original sources

USGS2000

Aerial-Photointerpretation of landslides along the Ohio and Mississippi rivers

A landslide inventory was conducted along the Ohio and Mississippi rivers in the New Madrid Seismic Zone of southern Illinois, between the towns of Olmsted and Chester, Illinois. Aerial photography and field reconnaissance identified 221 landslides of three types: rock/debris falls, block slides, and undifferentiated rotational/translational slides. Most of the landslides are small- to medium-size, ancient rotational/translational features partially ob-scured by vegetation and modified by weathering. Five imagery sources were interpreted for landslides: 1:250,000-scale side-looking airborne radar (SLAR); 1:40,000-scale, 1:20,000-scale, 1:6,000-scale, black and white aerial photography; and low altitude, oblique 35-mm color photography. Landslides were identified with three levels of confidence on the basis of distinguishing characteristics and ambiguous indicators. SLAR imagery permitted identification of a 520 hectare mega-landslide which would not have been identified on medium-scale aerial photography. The leaf-off, 35-mm color, oblique photography provided the best imagery for confident interpretation of detailed features needed for smaller landslides.

Illinois, Indiana, Kentucky, Missouri↗

USGS1997

Digital reproduction of historical aerial photographic prints for preserving a deteriorating archive

Aerial photography from the 1920s and 1930s is a unique record of historical information used by government agencies, surveyors, consulting scientists and engineers, lawyers, and individuals for diverse purposes. Unfortunately, the use of the historical aerial photographic prints has resulted in their becoming worn, lost, and faded. Few negatives exist for the earliest photography. A pilot project demonstrated that high-quality, precision scanning of historical aerial photography is an appealing alternative to traditional methods for reproduction. Optimum sampling rate varies from photograph to photograph, ranging between 31 and 42 ??m/pixel for the USDA photographs tested. Inclusion of an index, such as a photomosaic or gazetteer, and ability to view the imagery promptly upon request are highly desirable.

Photogrammetric Engineering and Remote Sensing↗

USGS1987

Remote sensing investigations at a hazardous-waste landfill

In 1976 state licensed landfilling of industrial chemicals was begun above an abandoned, underground coal mine in Illinois. Five years later organic chemical pollutants were discovered in a monitoring well, suggesting migration 100 to 1000 times faster than predicted by laboratory tests. Remote sensing contributed to the determination of the causes of faster-than-predicted pollutant migration at the hazardous-waste landfill. Aerial and satellite imagery were employed to supplement field studies of local surface and groundwater hydrology, and to chronicle site history. Drainage impediments and depressions in the trench covers collected runoff, allowing rapid recharge of surface waters to some burial trenches. These features can be more effectively identified by photointerpretation than by conventional field reconnaissance. A ground-based, post-sunset survey of the trench covers that showed that a distinction between depressions which hold moisture at the surface from freely-draining depressions which permit rapid recharge to the burial trenches could be made using thermal infrared imagery.In 1976 state licensed landfilling of industrial chemicals was begun above an abandoned, underground coal mine in Illinois. Five years later organic chemical pollutants were discovered in a monitoring well, suggesting migration 100 to 1000 times faster than predicted by laboratory tests. Remote sensing contributed to the determination of the causes of faster-than-predicted pollutant migration at the hazardous-waste landfill. Aerial and satellite imagery were employed to supplement field studies of local surface and groundwater hydrology, and to chronicle site history. Drainage impediments and depressions in the trench covers collected runoff, allowing rapid recharge of surface waters to some burial trenches.

Photogrammetric Engineering and Remote Sensing↗