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Geophysics
Geophysics successfully detects void beneath Missouri Taxiway PDF Print E-mail
Written by Randy Post   
Sunday, 21 April 2013 15:54
Excavation of void under a taxiway in Kansas City. The void was detected using geophysics.

Airport authorities at the Charles B. Wheeler airport in Kansas City, MO were concerned about a leaking CMP joint 22-feet beneath the taxiway. The sand that was coming through the joint was detected on a video inspection of the culvert. They were concerned about possible voids above the leak and commissioned a geophysical survey. Two geophysical methods were used, ground penetrating radar and multi-channel analysis of surface waves (MASW). The void was detected using the methods, and subsequent excavation of the airport taxiway confirmed the presence of the voids with about the same dimensions as what was indicated by the geophysics. The work was performed by the St. Louis office of Geotechnology, Inc. [Source: CE News. Image: CE News]

 
Archaeologists and PBS crew use geophysics and LIDAR PDF Print E-mail
Written by Randy Post   
Wednesday, 13 June 2012 16:30
Shanna Diederichs, Crow Canyon's supervisory archaeologist on the Dillard site dig, and Bruce Barrow, Time Team America producer, keep an eye on the production for the PBS archaeology show.

At an archaeological site at Crow Canyon, near Cortez, Colorado, a team of archaeologists, supported by a PBS film crew, were using ground penetrating radar, magnetometry, and resistivity geophysical methods to try to image the subsurface of the Basketmaker III community. They also used airborne LIDAR to map out structure locations, drainage and irrigation features and even old paths. [Source: The Cortez Journal. Image: Cortez Journal]

 
US Army testing new vehicle with ground penetrating radar PDF Print E-mail
Written by Randy Post   
Tuesday, 05 July 2011 15:32
Husky mounted detection system

The US Army's 2nd Brigade, 1st Armored Division, Special Troops Battalion has been testing the Husky Mounted Detection System at White Sands Missile Range in New Mexico. The vehicle is equipped with ground penetrating radar capable of detecting buried improvised explosive devices, or IEDs, and anti-tank land mines. [Source: The United States Army. Image: US Army]

 
Geophysicists using fiber optic cables in homeland security applications PDF Print E-mail
Written by Randy Post   
Sunday, 19 December 2010 14:23
Helios system screen shot of two horses crossing the line

Researchers from Zonge Engineering in my own Tucson, Arizona along with researchers at the University of Arizona's Mining and Geological Engineering Department (my alma mater) have completed a report on a fiber optic monitoring system that has wide-ranging applications in border security, prison perimeter protection, mine safety and other applications. The Helios system uses the principle of 'optical backscattering' to detect small acoustical vibrations, such as an illegal border crosser, or a trapped miner tapping on a wall. Because of the speed with which the lasers can travel in the fiber optic line, the system can be deployed in lengths up to 50-km, and can locate the source of a signal within 1-m. If there are source lasers at each end of the cable, they can even detect exactly where the cable is cut and it can continue functioning. [Source: UANews.org. Image: UANews.org]

 
Hanford nuclear waste retrieval resumes with better technology (GPR) PDF Print E-mail
Written by Randy Post   
Thursday, 01 July 2010 06:14
Loading contaminated soil into a truck near the Hanford Nuclear site. A former plutonium production reactor is in the background.

Ground penetrating radar (GPR) imaging of the subsurface tied to GPS mapping will allow the CH2M Hill Plateau Remediation Company to have a better idea of what is buried at the site before excavating for it's eventual disposal. Apparently without a permanent disposal facility, some of the hazardous and nuclear waste was temporarily buried on-site. Much of it was in well-organized pits, but some trenches have more issues. After some incidents over the past few months with the encountering of containers while excavating, the DOE, CH2M Hill and the Washington State Department of Ecology took a step back to evaluate their processes, and the GPR tied to GPS is apparently a good solution. [Source: The News Tribune. Image: EPA]

 
Single Borehole P-Wave and S-Wave Geophysics with PS-suspension Probe PDF Print E-mail
Written by Randy Post   
Friday, 20 November 2009 00:42

A Japanese company, OYO Corporation, created the PS-suspension probe for recording P-Wave and S-Wave velocity data in geomaterials using one borehole back in the 1980’s. A recent update to the probe has made it digital.

The probe is most frequently used in the off-shore oil and gas industry but has also been used on a limited basis in the US, most notably on several high-profile San Francisco Bay-area bridges. It has the capability of logging this data up to a depth of 500-m in an un-cased open, water-filled borehole. More info at New Civil Engineer.

Last Updated on Tuesday, 17 November 2009 23:55
 
Ground Penetrating Radar in Archaeology PDF Print E-mail
Written by Randy Post   
Wednesday, 23 September 2009 12:23
Ground Penetrating Radar or GPR as used in archaeology applications. Source: columbus Dispatch.

GPR is an increasingly popular geophysics tool for archaeologists to visualize what lies in the near subsurface thereby allowing them to fine-tune their excavation plans to more focused areas rather than an entire site. The Columbus Dispatch recently ran a nice article explaining to the lay-person what ground penetrating radar is and how it is used in archaeology. They also interviewed a local archaeologist who uses GPR and described how it was used on several local projects.

But I think the best thing about the article was the very nice figure showing the GPR being used, including the schematic, a sample radar reflection profile, an actual map produced from a gpr survey and the resulting exposed historic church foundations. A portion of the image is shown at left. Source: Columbus Dispatch.

Last Updated on Wednesday, 23 September 2009 12:23
 
Geophysics used to find 139 missing WWII Marines PDF Print E-mail
Written by Randy Post   
Wednesday, 10 December 2008 00:24

Marines take cover behind a sea wall on Red Beach #3, Tarawa. November 1943.Researchers have used ground penetrating radar in addition to hours of painstaking research to identify the graves of 139 US Marines killed on the South Pacific atoll of Tarawa. The Battle of Tarawa was a particularly bloody one with approximately 1,000 Marines killed and nearly 2,300 wounded in addition to 687 casualties from the US Navy. The Japanese soldiers were firmly entrenched in concrete bunkers and were "well supplied and well prepared and fought almost to the last man". Many of the dead were buried on the island in marked graves, but the small island became an important air base and many of the markers were moved and eventually forgotten. (Photo by USMC, Marines take cover behind a sea wall on Red Beach #3, Tarawa. November 1943.)

Mark Noah raised the money for the investigations to search for the remains of US soldiers through his nonprofit, History Flight, which charges for rides in vintage aircraft. This will hopefully be the first step in bringing these brave soldiers home for a proper burial at Arlington National Cemetary.

Sources: November 26, 2008 AP article Researchers: 139 WWII Marines entombed on atoll, November 25, 2008 article on Military.com - Searchers Say 139 Marine Graves Found. Military.com has a vintage news reel video on the Battle of Tarawa

 
Kansas Geological Survey uses Geophysics to Find Border Tunnels PDF Print E-mail
Written by Randy Post   
Tuesday, 05 February 2008 06:51

The Kansas Geological Survey has some interesting seismic equipment that they have used on behalf of the U.S. Department of Homeland Security to look for drug tunnels along the US-Mexico border. I've never seen anything quite like this. The sensors all appear to be placed within an old fire hose and mounted onto a Bobcat Toolcat utility machine. On the front of the vehicle is a cyllinder with a 60-lb weight that gets dropped. Read on. (Photo by Richard Gwin, LJWorld.com)

Last Updated on Tuesday, 05 February 2008 07:09