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USGS2010

The Plate Boundary Observatory Permanent Global Positioning System Network on Augustine Volcano before and after the 2006 Eruption: Chapter 19 in The 2006 eruption of Augustine Volcano, Alaska

In September of 2004, UNAVCO and the National Science Foundation (NSF) funded EarthScope Plate Boundary Observatory (PBO) installed five permanent Continuous Global Positioning System (CGPS) stations on Augustine Volcano, supplementing one existing CGPS station operated by the Alaska Volcano Observatory. All six CGPS stations proved crucial to scientists for detecting and monitoring the precursory deformation of the volcano beginning in early May 2005, as well as for monitoring the many subsequent small inflationary and deflationary episodes that characterized the 2006 eruption. Following the eruption, in September of 2006, PBO added six additional permanent CGPS stations. The 2006 eruption and its precursors were the first significant activity of the volcano in 20 years and the PBO CGPS network provided an unprecedented opportunity to monitor and detect volcanic ground deformation on an erupting Alaskan stratovolcano. Data from the new CGPS stations coupled with the existing seismic stations provided scientists with the first real opportunity to use geodetic data and real time seismic data to assess the volcanic hazards before, during, and after an Alaskan eruption.

Alaska↗

USGS1995

Deep tunnel detection using crosshole radar tomography

As part of continuing research aimed at the detection of subsurface tunnels and voids, the U.S. Bureau of Mines recently completed a cooperative study with the U.S. Geological Survey at a surface gold mine in the Black Hills mining district of South Dakota. The occurrence of older, poorly mapped mine workings in the section create a consistent health and safety concern for mine employees as well as economic concerns about potential damage to equipment during daily operations at the mine. Accurate knowledge regarding the location of these abandoned tunnels prior to interception by the current mining operation would be beneficial. Previous research efforts on site have demonstrated the suitability of several surface geophysical technologies in detecting shallow workings which present an immediate problem in the safe conduct of the mine operation. Another concern is the existence of deeper abandoned mine tunnels, which occur further in advance of the surface mining operation. In the design and development of a new mine pit, the placement of access roads over a tunnel would be hazardous, due to the volume of traffic and the weight these haulage trucks can carry. In this study we evaluate cross borehole radar tomography methods which might be used to image mine openings in the deep subsurface, and lead to more prudent placement of pit haulage roadways. A pulsed radar system was used to collect both velocity and amplitude information about local rock conditions, and multiple borehole data allowed for the use of 3-D imaging techniques.

South Dakota↗