Janet E. Simms

Multidisciplined investigation to locate theKentucky shipwreck

A local artifact collector contacted the U.S. Army Engineer District, Vicksburg in the fall of 1994 concerning timbers from a ship protruding from the west bank of the Red River, Louisiana, during the summer of 1994. From historical records it was determined that the shipwreck is that of the Kentucky, which sank in 1865. An investigation integrating archaeological, geological, and geophysical methods was undertaken to determine the location, orientation, and depth of the wreckage. Based on site geology, the shipwreck is expected to lie within a silty sand deposit within 4–8.5 m below the ground surface. The results of probe investigations performed by the archaeologists and borehole data orient the long axis of the ship N57.5E. This orientation conflicts with the geophysical data, which suggest an orientation of N116W. The geophysical surveys identified an anomalous region, approximately 31 m long and 10 m wide, that borders the Red River and an abandoned channel of the Red River. The magnetometer data suggests that the bow of the ship is pointed toward the abandoned channel. This orientation contradicts historical records which have the bow pointing toward the modern Red River. A subsequent underwater investigation by the archaeological contractor discovered a rudder-related mechanism protruding from the bank of the Red River, confirming the geophysical prediction. All three scientific surveys agree that the wreckage is at a depth 3.8–8.5 m below ground surface and at an inclined position, with a downward slope from the bank of the Red River to the abandoned channel.

Evaluation of Seismic-Acoustic Analysis Methods for a Real-time UXO Monitoring System

The Department of Defense (DoD) uses over two million rounds of high-explosive (HE) munitions per year (Defense Science Board Task Force, 2003). A small percentage does not explode, thus generating unexploded ordnance (UXO) in current range areas at a substantial rate. As these ranges are closed, the DoD becomes responsible for the environmental restoration of the affected properties. Current methods of UXO remediation are costly because of high false alarm rates. Our current research is to develop a complementary technology that will alleviate false alarm rate by detecting, classifying, and locating UXO in near real time (less than 1 minute) as a munition impacts the range. This technology will utilize an array of buried seismic sensors in a calibrated range area, along with a set of algorithms based on theoretical and applied seismology and statistical analysis. Initial field tests at three sites focused on developing concepts of the seismic and acoustic location of ordnance impacts. Our research program developed from these initial field tests has four primary objectives: 1) fully implement a wired seismic-acoustic ordnance impact location system for live fire ranges; 2) develop a system capability to discriminate high-order (HE), loworder (partially exploded), and zero-order (UXO) events; 3) reduce location error to a stringent program metric of 1–2 m; and 4) investigate the feasibility of developing a wireless implementation of the technology. This paper describes the procedures and results from follow-on tests that were conducted in two locations at the U.S. Army Aberdeen Proving Ground (APG), Maryland. These tests were used to evaluate potential seismic-acoustic methods and system configurations for a Seismic-Acoustic Impact Monitoring Assessment (SAIMA) system for mitigating UXO hazards. Significant results from this work include: 1) seismic impulses from low-order impacts were detected at distances up to 1,000 meters; 2) classification features based on measurements of the amplitude of acoustic and seismic phases produce clear discrimination between HE and UXO impacts; 3) calculated location solutions for HE and UXO impacts yield an average location error of 10–20 meters; and 4) empirical observation and waveform modeling demonstrated that surface waves dominate the signal at all distances and therefore should be the primary phase used for all components of analysis. Furthermore, these tests demonstrated the current system design, allowing further enhancements, is capable of meeting the initial research objectives (1) and (2). Future research will focus on improving system performance with refinement of the sensor-layout geometry and the detection and location algorithms through system error analyses and follow-on field testing.

Review of Magnetic Modeling for UXO and Applications to Small Items and Close Distances

Abstract Prior to 1990, UXO were generally modeled or approximated as compact, ferrous objects; the model was effectively a uniformly magnetized sphere of iron at a specified or an unknown distance from the magnetic sensor. Correlations were developed between various UXO, represented as compact masses of iron, and magnetic anomaly signature features such as maximum positive value, peak-to-peak value, and wavelength. The uniformly magnetized sphere, equivalent to a point dipole model external to the sphere, cannot account for magnetic phenomenology of actual UXO, which exist in forms ranging from approximately spherical to highly elongated, with elongations as large as 5 (ratio of length to diameter). UXO are generally ferrous, with large magnetic permeability, although some can contain aluminum or other non-magnetic metals. This paper reviews the phenomenology of models applied to simulation of UXO magnetic anomalies. The multipole expansion solution of the prolate spheroid model in earths magnetic field...

In Situ Root Volume Estimation Using Ground Penetrating Radar

ABSTRACT A ground penetrating radar (GPR) and root excavation study were conducted to determine the efficacy of GPR for estimating subsurface tree root volume. The survey was conducted in sandy soil, which is favorable for GPR imaging. The tree was a loblolly pine (Pinus taeda) that was isolated from other trees to minimize outside influences. GPR antenna frequencies of 450 MHz, 900 MHz, and 1200 MHz were used to map subsurface profiles over a 9-m2 sample grid, and six 1-m2 cells of the root system were subsequently excavated to a depth of 1 m for verification. The 900 MHz GPR was successful at mapping the larger tree roots (>2 cm) and some smaller roots (<2 cm). A simple approach based on average signal strength was used to estimate root volume from the GPR data. The total root volume estimate based on the GPR data compared well with the total root volume determined from the in situ measurements when information from all of the excavated cells was used (<2% error). However, accuracy reduced significantly...

Initial Development of a High-frequency EMI Sensor for Detection of Subsurface Intermediate Electrically Conductive (IEC) Targets

The U.S. military has developed and currently uses composite material munitions. These composite munitions are typically comprised of carbon fiber and, because of their low electrical conductivity, have a much lower electromagnetic induction signature, which makes them difficult to detect using traditional metal detecting methods. The term intermediate electrically conductive (IEC) is used to describe these lower conductivity materials, with conductivity, σ , typically in the range 10 σ 5 S/m. The electromagnetic induction (EMI) relaxation response of carbon fiber munitions peaks in the low megaHertz range (

Evaluation and Current Results of the Seismic Acoustic Impact Monitoring Assessment (SAIMA) System

For the past several years, Quantum Technology Sciences (QTSI) and U.S. Army Engineering Research and Development Center (ERDC) have been developing a system to actively sustain present and future artillery ranges at zero unexploded ordnance (UXO) gains. With the Department of Defense (DoD) using over two million high-explosive (HE) munitions per year with a significant fraction as UXO, reducing costly range remediation and environmental restoration efforts will offer significant savings. The developed Seismic Acoustic Impact Monitoring Assessment (SAIMA) system is not designed for past ranges, but as a complementary technology to detect, locate within two meters, and classify UXO in near realtime to aid existing cleanup technologies. Feasibility and descriptions of system components have been previously provided (VanDeMark et al., 2009, 2010, 2013). The current system is composed of multiple buried seismic arrays encircling a mortar or artillery impact area, communications from the arrays to a central processing station, and a processing unit that employs an algorithm suite based in the seismology and statistical analysis disciplines to detect, locate, and classify the HE or UXO impact. Recent deployments of the SAIMA system have demonstrated hardware maturity and algorithm refinements to nearly enable the goal of locations within two meters. A field deployment at Ft. Sill, Oklahoma, in June 2012 demonstrated acoustic locations at a large range (QTSI, 2012). Subsequent systems tests with five arrays using a synthetic UXO source (kinetic source only; no acoustic phases) on a small field (80 m by 80 m) resolved locations within 0.5 m of ground truth with coverage ellipses at 0.1 m 2 (time and azimuth). On a small mortar field,