he pulseEKKO® Ultra Receiver, which operates with 12.5, 25, 50, 100 and 200 MHz antennas and stacks data traces up to 65,536 times, has been available for more than one year now and we thought it would be a good time to share a few real-world results from our customers who have been using this new technology in the field.
Dr. Sarah Kruse from the University of South Florida with her students, PhD candidates Danielle Molisee and Elisabeth Gallant, used an Ultra Receiver as part of an interdisciplinary investigation of the eruptive history of Medicine Lake Volcano in Northern California.
Danielle Molisee states, “The Glass Mountain eruption (~870 yrs B.P.) blanketed the area in tephra and buried the evidence of some earlier eruptions. We’re using GPR to reveal these hidden eruptions (Figure 1). Considering this new information, we can much better understand the past behavior of this volcano, which in turn, should help us to better forecast future behavior.”
Dr. Harry Jol and his students, from the University of Wisconsin at Eau-Claire, collected pulseEKKO® Ultra Receiver data at a site in Lithuania suspected of being used by the Nazis for the mass execution of Jews in 1941-44. Previous work at the same site showed the soil has high electrical conductivity that limited GPR signal penetration. By stacking each trace 16,384 times, the depth of penetration of the 200 MHz antennas more than doubled (Figure 2b) when compared to stacking once (Figure 2a); resulting in the detection of deeper features than ever before.
Michael Powers from the U.S. Geological Survey is using the Ultra Receiver with his pulseEKKO® borehole GPR system to detect weaker GPR signals traveling between boreholes. He typically collects ZOPs, Zero Offset Profiles (Figure 3) where the transmitting antenna and the receiving antenna are lowered down two boreholes at the same time and data collected at equal intervals.
The increased stacking provided by the Ultra Receiver means that weaker GPR signals can now be detected as they travel from one borehole to the other, providing more information about the properties of the materials between the boreholes.
Another American researcher recently used the Ultra Receiver for an extensive survey in a glacial environment with the purpose of mapping the subsurface glacial, glaciofluvial, and glaciolacustrine geology (Figure 4).
As these examples show, the pulseEKKO® Ultra Receiver is proving itself in many varying applications by increasing the depth of penetration, even in areas with high signal attenuation.
We thank those who contributed and allowed us to share their data and stories.
