The Department of the Interior (DoI) continued to depend on the DoD Navstar GPS Precise Positioning Service (PPS) for real-time positioning in wildland areas that are out of reach of traditional differential GPS methods. DoI user growth for GPS exceeded training capacity; the USGS facilitated five 2-day training sessions for DoI in FY 1998, and more GPS training courses were scheduled for FY 1999. DoI GPS coordinators continued to identify DoI requirements for specifications of future military handheld GPS receivers, such as the Special Operations Lightweight GPS Receiver and the Defense Advanced GPS Receiver.

The Office of Surface Mining (OSM) used GPS technology to locate surface resources to determine their premining status and condition and to confirm that reclamation efforts have adequately restored regular inspection. On abandonethese resources. On active mines, inspection staff used GPS to determine reclaimed acreage and to locate features that require d mine lands, Office of Surface Mining staff used GPS to quickly assess the disturbed areas and features to facilitate the preparation of reclamation plans and contracts. In addition, Bureau of Reclamation personnel often used GPS for such applications as locating sampling sites to study geologic features, vegetation, and water quality, mapping infrastructure locations, and mapping environmental features such as wetland boundaries.

Ed Harne of BLM at joint BLM/USGS Bering Glacier Field Camp (photo by Bruce Keating, BLM).

The USGS Volcano Hazards Program expanded its volcano-monitoring network at Long Valley, California, by installing additional GPS sensors during FY 1998. The expansion of this GPS network was set to continue over the next 2 years, resulting in a modern instrument array capable of continuous, real-time detection of ground deformation associated with potential volcanic activity in this seismically active area.

USGS scientists used a 63-station GPS network to measure the distribution of subsurface bedrock deformation across the western United States through surveys conducted in 1992, 1996, and 1998. Subsurface bedrock deformation was determined to be quite variable across the region and is influenced by patterns of fault networks and plate tectonic processes. Maximum deformation of 6.0 ± 1.6 millimeters per year occurred near the Sierra Nevada Mountain range, reflecting a concentration of deformation adjacent to the rigid Sierra Nevada and Colorado Plateau blocks.

The Bureau of Indian Affairs extensively used Landsat and Satellite Pour l'Observation de la Terre (SPOT) satellite imagery, digital orthophotography, National Aerial Photography Program (NAPP) and other aerial photography, and GPS-derived data to generate image maps, inventory natural resources, conduct environmental assessments, and support other Geographic Information System (GIS) analyses.

Remotely sensed data derived from satellites and aircraft sensors and GPS technology continued to play an important role in efforts by the Bureau of Land Management (BLM) to sustain the health, diversity, and productivity of the public lands. The data provided critical information to resource specialists in the field for use in their inventory, assessment, modeling, and monitoring efforts. BLM has significantly increased the use of GPS and GIS technology to implement the Automated Lands and Minerals Record System Modernization program. As a result, many BLM offices were able to perform complex spatial data analysis at the field office level.

The Bureau of Reclamation used remotely sensed data in support of a number of water resource management projects. The bureau derived crop acreage from Landsat Thematic Mapper (TM), SPOT high-resolution visible, Indian Remote Sensing Satellite (INSAT) panchromatic, and Radarsat data as inputs to consumptive water use models for the Colorado and Yakima River basins in the western United States. Scientists mapped in-channel and flooded bottomland habitat in the Yakima basin, using large-scale aerial photography, and mapped surface temperatures in the Yakima River, using airborne scanner imagery. Reclamation scientists also used medium- to large-scale aerial photography to support a number of resource mapping projects at selected Federal lands throughout the western United States. NASA acquired Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) hyperspectral imagery of the Owyhee River basin in eastern Oregon for the Bureau of Reclamation to use in support of surface geology and water quality mapping projects.

The National Park Service used Landsat and SPOT data, along with conventional aerial photography, to map and monitor land cover, vegetation, and other specific features in many National Parks, from Alaska to Florida.

The USGS EROS Data Center continued to work with NASA and NOAA to prepare the facilities to receive, process, and deliver data from the Landsat 7 satellite, which is planned for launch in 1999. The Landsat 7 Processing and Image Assessment Systems became operational in 1998. On September 17, 1998, the new Landsat 7 antenna successfully acquired the first Landsat image that the EROS Data Center had ever acquired directly from a Landsat satellite—a TM image of the Black Hills of South Dakota.

The Multi-Resolution Land Characterization project—a joint activity of the USGS, the Environmental Protection Agency (EPA), NASA, NOAA, and other agencies—released medium-resolution land-cover data derived from Landsat data for the States of Alabama, Florida, Georgia, Kentucky, Mississippi, and Tennessee. Scientists successfully tested an accuracy assessment methodology in Federal Region 2 (States in the Chesapeake Bay watershed) and applied the methodology in New York and New Jersey. The USGS also continued to build the Alaska Multi-Resolution Land Characterization data base. This data base contains land-cover maps derived from Landsat Multispectral Scanner, Landsat TM, and SPOT satellite data, dating back to 1980.

The USGS worked with the USDA Forest Service to incorporate satellite-derived fire fuels information into the Forest Service's Fire Potential Index (FPI) model. Technicians installed the enhanced model at nine national study sites where fire managers began using it in daily local fire hazard briefings. Forest Service fire managers at the national level used the FPI to allocate funding to the field for the 1998 fire management and suppression season. The model is also being applied internationally; fire managers, suppression experts, modelers, and geospatial analysts from Argentina, Chile, Mexico, Spain, and the United States met in Argentina to complete fire fuels maps for these countries that will be used to calculate the FPI for 1992 through 1997.

The USGS National Civil Applications Program (NCAP) provided secure facilities for Federal civil agencies to acquire and process classified satellite data for applications such as land and resource management, global change research, environmental monitoring, and disaster detection and mitigation. In addition, NCAP supported a national wildland fire detection and global volcano monitoring network, maintained and preserved a global library of classified remotely sensed data, and trained civil users. In FY 1998, NCAP staff began testing the prototype Hazards Support System, which will provide warnings of wildland fire outbreaks in the United States and monitor volcanic eruptions worldwide. They also began developing and testing the Global Fiducials Library, which provides the scientific community with digital classified satellite data collected at selected worldwide sites for long-term environmental monitoring.

The USGS Alaska Volcano Observatory began using a variety of real-time and archival satellite data and computer modeling techniques to monitor and analyze volcanic activity in the North Pacific region. During FY 1998, the observatory provided information about airborne volcanic ash from several volcanic events to the National Weather Service, the FAA, and the U.S. Air Force to assist in weather forecasting and air traffic control.

USGS scientists demonstrated that satellite Interferometric Synthetic Aperture Radar (InSAR) is uniquely suited to monitoring year-to-year deformation of the entire 3,000-square-kilometer Yellowstone Caldera that underlies Yellowstone National Park. Sequential interferograms indicated that subsidence within the caldera migrated from northeast to southwest, from one resurgent dome to the other, between 1992 and 1995. Subsidence of the caldera ceased in 1995–96, but it began again in 1996–97. These patterns of subsidence are matched well by other measures of the migration of hydrothermal and magmatic fluid throughout the entire caldera floor at a depth of approximately 8 kilometers.

USGS scientists used a variety of remote-sensing and spatial analysis tools for environmental analysis and modeling in Everglades National Park and surrounding areas. Airborne, ground, and borehole geophysical methods were used to map saltwater intrusion and develop three-dimensional water quality models. Scientists used more than 1,500 satellite images to derive a time series of water turbidity conditions in Florida Bay since 1985. Scientists used these images to determine turbidity and light availability for seagrass and to assess conditions in the bay and adjacent areas prior to the time when extensive monitoring programs began in 1991. An analysis of the imagery indicated that 200 square kilometers of dense Everglades seagrass meadows were lost between 1987 and 1997.

The USGS Astrogeology Program continued to make major contributions to Martian exploration. With the successful completion of operations of the Mars Pathfinder spacecraft, USGS scientists turned their attention to the creation of special digital images, image mosaics, and topical science issues on the characteristics of the rocks, soils, and terrain at the landing site. The USGS was also involved in both the Mars Orbital Camera and the Thermal Emission Spectrometer teams of NASA's Mars Global Surveyor mission, assisting with observations and analyses to guide the spacecraft through its critical aerobraking phases as it settled into low Martian orbit.

In addition, USGS investigators played a major role in shaping the design of NASA's new and highly aggressive Mars Exploration Strategy. This plan includes two spacecraft launched to Mars every 2 years for the next 10 years, culminating in the return of Martian surface samples in about a decade and the exploration of the planet by humans approximately a decade later.