Applied Geophysics at the Mackay School of Mines

For more information, contact John Louie
Additional resources: a folder of selected high-resolution photos and illustrations; the photo of the minute.

Professionals and Students Working Together

Mackay faculty and students from the Hydrogeology program examine seismic survey results from Thomas Creek, south Reno in October 1995. Hydrogeology graduate programs have attracted many top-notch local professionals to return to school, such as USGS scientist David Berger at the center. Although enrolled as a student in the course Geol 492/692, Environmental Exploration Geophysics, Berger operated USGS-owned surveying equipment during class field exercises. Mackay partners continually with local government and industry to advance earth science and engineering. The W. M. Keck Foundation recognized these partnerships the following year by donating high-resolution seismic surveying equipment to Mackay that very few institutions can match. (Photo by J. Louie) More hydrogeophysics photos....

Progressive slices into a 3-d volume of high-resolution seismic data across the Pahrump Valley fault (PVF) on the Nevada-Calif. border west of Las Vegas. Mackay's Geol 453/653 Geophysical Applications class recorded the survey in Spring 1996 during the class's one-week geophysical field camp. Field operations were supported by an NSF Geophysics program grant to Prof. J. Louie; the W. M. Keck Foundation had recently donated the seismic recorder. The Pahrump Valley fault is seen here as an interruption in stratigraphy dipping about 80 degrees left (SW) from 24 to 73 m depth in this volume. A lateral stratigraphic pinchout at 24 m depth is offset at least 18 m in right-lateral strike slip. Given the 10-450 ka age constraints on the stratigraphy, our work establishes a fault slip rate above 0.1 mm/yr. The PVF thus contributes major earthquake hazard to the Las Vegas region. Las Vegas hazard studies are in the mandate of Mackay's Seismological Lab, which is chartered for statewide research and public service. (Illustration by J. Louie) More about the Pahrump Valley fault zone....

The Urban Environment

Mackay Geophyiscs major Christine Mann and Geophysics Ph.D. student Robert Abbott establish geodetic GPS elevation and gravity along South McCarran Blvd. in Reno. Mackay's new focus on urban environmental and earthquake hazards required the collection of many new data sets. Since sedimentary basin depths influence both potential earthquake shaking, and gravity readings, the U.S. Geological Survey funded the Seismological Lab to collect 300 gravity readings in Reno and Carson City during the summer of 1997. Research funding helps support and retain undergraduate students at Mackay. Such support helped Mann to choose a Mackay major over a traditional pre-med program; she begins medical school at Nevada in Fall 2000. (Photo by J. Louie)

Analysis of gravity data collected in the Reno area for effects of basin sediments. Orange areas have exposed bedrock; blue shows gravity lows (in mGal) associated with basin depths of as much as 1.5 km. This work was funded by the U.S. Geological Survey. Surprisingly, the largest sediment thicknesses in Reno are on the west side of the city, below West McCarran Blvd. The shaking from local or even distant large earthquakes can be significantly amplified by this deep basin. (Illustration by R. Abbott) More about gravity and basin depths in Reno....

Basic Research in Earth Science

In a 1995 project Mackay's Seismological Lab teamed up with the Jet Propulsion Lab and the University of Utah to investigate Upheaval Dome, in Canyonlands National Park, with NASA funding. Probing the structure required helicopter placement of seismic recorders across the extreme topography of the Canyonlands. Mackay's seismic profiles proved that Upheaval Dome could not have originated as a salt uplift, and must be the largest exposed meteor impact structure in the West. (Photo by J. Louie) More about the Upheaval Dome impact....

Nevada's Unique Tectonics

Nevada Precision Drilling and Blasting places a shot hole for Mackay's 1998 seismic survey of Dixie Valley, funded by the NSF. Job Peak is in the background, with the 1954 earthquake scarp at its base. Louie, Wesnousky, and Caskey used geophysical surveys to test a hypothesis that the 1954 rupture was along a low-angle normal fault. Students in Louie's Geol 453/653 Geophysical Applications class performed all fieldwork except drilling and blasting, as their one-week geophysical field camp. Mackay students participate in the latest earth-science research both in class and on the staff of funded projects. (Photo by J. Louie) More Dixie Valley photos....

Photo of the 1954 Dixie Valley rupture taken the day after the earthquake by seismologist Carl V. Steinbrugge. The miner's cabin rests within the unusually wide fault graben, which is the area seamed by extensional cracks. Mackay geologists Steve Wesnousky and S. John Caskey established the constant 15 m width of this graben over a 50 km length of the fault, suggesting the low-angle normal rupture. Our Spring 1998 geophysical work confirmed that the low-angle normal fault extends to 3 km depth, and has maintained its low angle since basin inception 15-20 million years ago. Dixie Valley thus contains the world's only proven low-angle normal fault. (Photo courtesy of the Steinbrugge Archive of Earthquake Photographs and the U.C. Berkeley Earthquake Engineering Research Center) More about the Dixie Valley fault....