Evaluation of Foot Protection Effectiveness Against AP Mine Blasts: Effect of Deflector Geometry

2016 ◽  
Vol 45 (2) ◽  
pp. 20150171 ◽  
Author(s):  
Murat Kamberoğlu ◽  
Mehmet Karahan ◽  
Can Alpdoğan ◽  
Nevin Karahan
Keyword(s):  
Mine Blasts

Spectral characteristics of regional phases recorded at Noress

1988 ◽  
Vol 78 (2) ◽  
pp. 708-725
Author(s):  
Anne Suteau-Henson ◽  
Thomas C. Bache
Keyword(s):  
Soviet Union ◽  
Nuclear Explosion ◽  
Spectral Characteristics ◽  
Low Frequency ◽  
Spectral Ratio ◽  
Spectral Ratios ◽  
Data Set ◽  
Nuclear Explosions ◽  
The Soviet Union ◽  
Mine Blasts

Abstract The spectral characteristics of Pn and Lg are studied for regional events recorded at the NORESS array in Norway. The emphasis is on the potential value of spectral ratios for identifying events as earthquake, chemical explosions, and nuclear explosions. The events studied include a suite of explosions from the Titania Mine in southwest Norway, a suite of events of unknown source type from a site offshore about 90 km from this mine, suites of explosions from several mines in the Soviet Union about 1000 km from NORESS, events from several locations along the 90° azimuth from NORESS, an apparent earthquake in the North Atlantic, and a nuclear explosion (PNE) at a range of 1560 km. The event identification issues addressed are as follows: (1) Can earthquakes and explosions be identified based on the ratio of high- and low-frequency energy in their signal spectra? (2) Do spectral ratios separate mine blasts from earthquakes for all source areas? (3) Will spectral ratio discriminants be effective for identifying decoupled underground nuclear explosions? We conclude that spectral ratios can sometimes separate events. An example is separation of the Titania mine blasts from the events at the nearby offshore locations, although we cannot be sure how much this is due to path differences. However, in general, spectral ratios vary as much within classes of events as they do among different classes. The PNE in our data set allows the simulation of spectra from a decoupled nuclear explosion by simply applying the frequency-dependent decoupling factor to the observed Pn spectrum for this event. After applying a distance correction, the spectrum for this simulated decoupled nuclear explosion is similar to those for the Soviet Union mine blasts in our data set.

Testing a Local-Distance Rg/Sg Discriminant Using Observations from the Bighorn Region, Wyoming

2020 ◽  
Vol 110 (2) ◽  
pp. 727-741 ◽  
Author(s):  
Jonas A. Kintner ◽  
K. Michael Cleveland ◽  
Charles J. Ammon ◽  
Andrew Nyblade
Keyword(s):  
Sedimentary Basins ◽  
Site Amplification ◽  
Source Material ◽  
Spectral Amplitude ◽  
Single Shot ◽  
Mountainous Terrain ◽  
Geometrical Spreading ◽  
Propagation Models ◽  
Local Distance ◽  
Mine Blasts

ABSTRACT This study explores the effectiveness of local-distance (<200  km) seismic discriminant to distinguish between surface mine blasts, single-shot borehole explosions, and earthquakes in the Bighorn Mountains region, Wyoming. We focus on the ratio between local-distance fundamental-mode surface waves (Rg) and the crustal shear-wave (Sg) signals. The observed spectral amplitude measurements are fit to propagation models that account for distance-dependent geometrical spreading and attenuation, and site amplification factors. The results support previous observations that Rg attenuates rapidly, is amplified in sedimentary basins, and has suppressed amplitudes in isolated mountainous terrain. Sg attenuates less rapidly than Rg but exhibits a similar spatial site amplification pattern. We compute an Rg/Sg source discriminant by taking the ratio between site- and distance-corrected Rg and Sg amplitude measurements. The results suggest that the site- and distance-corrected Rg/Sg ratios can distinguish events larger than ML∼1.5 (in the Bighorn region). The discriminant may also be sensitive to explosion emplacement conditions, where the ratios are higher for borehole shots in sedimentary strata and lower for explosions within the basement. The analysis shows that the Rg/Sg discriminant is effective for events in the Bighorn region for events larger than ML∼1.5 if proper considerations are made to account for event size and near-source material.

An Idaho‐Nevada‐California refraction experiment: utilizing large mine blasts for long‐range profiles

2005 ◽  
Author(s):  
Michelle Heimgartner ◽  
James B. Scott ◽  
Weston Thelen ◽  
Christopher T. Lopez ◽  
John N. Louie
Keyword(s):  
Long Range ◽  
Mine Blasts

Seismic radiation patterns of mine blasts

2021 ◽  
Author(s):  
Florian Bleibinhaus ◽  
Bernd Trabi
Keyword(s):  
Iron Ore ◽  
Reduction Potential ◽  
Homogeneous Model ◽  
Elastic Model ◽  
Radiation Patterns ◽  
Iron Ore Mine ◽  
Delay Times ◽  
Seismic Vibrations ◽  
Sensitive Structure ◽  
Mine Blasts

<p>Seismic vibrations induced by mine blasting are often a nuisance to residents and may even threaten the integrity of sensitive structure in the vicinity of mines. In this study we investigate the potential to reduce such vibrations through the interference with a second blast sequence. Assuming perfectly repeatable source wavelets and an acoustic, homogeneous model, we predict the radiation patterns of blast sequences with the Fourier shift theorem as a function of azimuth and incidence, and we benchmark those predictions with observations from a seismic array deployed at the iron ore mine Mt Erzberg, Austria. We then use our model to optimize the delay times of blast sequences with an inverse algorithm geared towards minimizing the predicted vibrations in certain target zones. Due to its symmetry, a single row of blasts has no azimuthal reduction potential. A second, quasi-simultaneous mine blast can, however, reduce blast-induced vibrations by up to 20% according to our model. In this study, we discuss the principles and the potential of this approach to vibration reduction. In a second study, we will present applied results obtained with a fully elastic model.</p>

Spectral evidence for source multiplicity in explosions: Application to regional discrimination of earthquakes and explosions

1988 ◽  
Vol 78 (5) ◽  
pp. 1773-1795
Author(s):  
Douglas R. Baumgardt ◽  
Kathleen A. Ziegler
Keyword(s):  
Simulation Studies ◽  
Nuclear Explosions ◽  
Western Norway ◽  
Cepstral Analysis ◽  
Delay Times ◽  
Individual Source ◽  
Multiple Shot ◽  
Mine Blasts ◽  
Regional Discrimination ◽  
Mine Explosions

Abstract Spectral and cepstral analysis were performed on regional-array NORESS recordings of mining explosions in Scandinavia and Russia in order to detect the effects of delayed explosions or “ripple firing” commonly used in mine-blasting practice. NORESS array-stacked spectra, corrected for instrument and noise, were computed in windows on Pn, Pg, Sn, and Lg waves from the mine blasts by averaging individual channel spectra, frequency by frequency, across the array. For comparison, spectra were also computed for six western Norway earthquakes located near the Blasjo and Titania Norwegian mines. Also, stack spectra of P coda, Sn, and Lg were computed using NORSAR seismograms for presumed peaceful nuclear explosions (PNEs) located at near-regional distances (Δ > 10°) in western Russia. The NORSAR spectra were determined in the same manner as the NORESS spectra, except that an individual source correction was applied to the spectra. Comparison of western Norway mine-blast spectra and nearby earthquakes shows that the earthquake Pn spectra are peaked in the 8- to 16-Hz band, with little energy below 6 Hz, whereas the explosion spectra have flatter spectra from 3 to 16 Hz. This difference in the Pn spectra may be caused by the earthquakes occurring at greater depths than the explosions, differences in the near-source media, or source mechanism effects in the earthquake spectra. The main difference between earthquake and explosion spectra is that the explosion spectra exhibit marked scalloping or modulation patterns not observed in the earthquake spectra. The modulation patterns are identical in spectra of all phases, indicating that they are caused by multiple-shot sequences or ripple firing. Simulated multiple-source spectra, determined using the NORESS seismograms for one of the western Norway earthquakes, resulted in spectra that resembled many of the explosion modulation patterns. Based on the simulation studies and cepstral analysis of the spectra, the mine explosions appear to be composed of two to three separate explosions delayed by between 80 to 150 msec. Moreover, the NORSAR spectra of PNEs indicate that these signals are also produced by multiple explosions, although they have larger delay times of between 0.9 to 1.5 sec. These results show that spectral modulations in seismogram spectra of economic explosions, including mine explosions and nuclear explosions fired for peaceful, economic purposes, can be used to distinguish them from earthquakes and nuclear-explosion weapons tests.

Shock Optimization in a Military Vehicle With Internal Space Frame

2009 ◽  
Author(s):  
Jagadeep Thota ◽  
Mohamed B. Trabia ◽  
Brendan J. O’Toole
Keyword(s):  
Structural Integrity ◽  
Impact Load ◽  
Random Search ◽  
Search Space ◽  
Quadratic Approximation ◽  
Internal Space ◽  
Space Frame ◽  
Military Vehicles ◽  
Space Frames ◽  
Mine Blasts

Space frames are usually used to enhance structural strength of the vehicle while reducing its overall mass. These frames are comprised of beams that are joined together. Recently, space frames are being incorporated in military vehicles. Space frames in military vehicles are however subjected to different types of loading than what is encountered in civilian vehicles such as projectile impacts and land mine blasts. Due to the need to replace a damaged section of the space frame quickly, the proposed space frame is composed of hollow square cross-section bars and angle sections that are bolted together. The space frame is enclosed by uniform-thickness armor, except at the turret. The vehicle is subjected to high impact load to simulate a projectile hit. The objective of this work is to minimize shocks at various critical locations of the space frame while maintaining the overall structural integrity of the vehicle. The vehicle model is parameterized to achieve this objective. This problem is solved using the Successive Heuristic Quadratic Approximation (SHQA) technique, which combines successive quadratic approximation with an adaptive random search within varying search space. The entire optimization process is carried out within MATLAB environment.

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