Exploration Geophysics - Using Tools to See Underground

Monitoring Nuclear Explosions

Since the advent of nuclear non-proliferation agreements, most nuclear nations have agreed to stop testing nuclear weapons. How do we know all parties abide by this agreement? By using geophysics, we can search for formations typical of underground nuclear explosions (spalling and collapse chimneys), helping to ensure that all sides are obeying the treaty.

Finding Underground Structures

Using gravity and magnetic differences in the earth, we can identify buried underground facilities. For example, we hooked our extremely sensitive gravity equipment to a remotely controlled 'CYPHER' from Sikorski (pictured above). By flying this equipment over a site where a buried structure was suspected, we identified a magnetic anomaly - indicating 'something' under there. The image to the right is a graph of the magnetic data obtained by using the CYPHER to fly over the 'cloud chamber,' an underground structure built at our own Nevada Test Site in the 1960s.

We can do similar studies using very sensitive measurements of gravity.

Environmental Characterization

Vibrating or hitting the ground with special devices sends seismic waves through the ground in all directions. When these waves meet a different type of rock or sedimentary layer underground, they may be deflected. By setting out a series of devices to record these seismic waves, we can map shallow underground drainage features. This can help with environmental clean up and studies.In the picture to the right, Allen Cogbill of GEO/EES-11 sets out an array of instruments to help identify subsurface drainage in Bayo Canyon near Los Alamos.