ON THE PROSPECTS OF THE IMPLEMENTATION IN DAGESTAN OF NEW TECHNOLOGIES OF OBSERVATION AND TREATMENT OF HIGH-FREQUENCY SEISMIC NOISE

2019 ◽  
Vol 3 (78) ◽  
pp. 45-51
Author(s):  
D.G. Taymazov ◽  
Keyword(s):  
High Frequency ◽  
Seismic Noise ◽  
New Technologies

High-frequency seismic noise as a function of depth

1991 ◽  
Vol 81 (4) ◽  
pp. 1101-1114
Author(s):  
Jerry A. Carter ◽  
Noel Barstow ◽  
Paul W. Pomeroy ◽  
Eric P. Chael ◽  
Patrick J. Leahy
Keyword(s):  
New York ◽  
High Frequency ◽  
Seismic Noise ◽  
Low Frequency ◽  
Time Variability ◽  
Orthogonal Components ◽  
The Difference ◽  
Frequency Coherence ◽  
Cultural Noise ◽  
Natural Wind

Abstract Evidence is presented supporting the view that high-frequency seismic noise decreases with increased depth. Noise amplitudes are higher near the free surface where surface-wave noise, cultural noise, and natural (wind-induced) noise predominate. Data were gathered at a hard-rock site in the northwestern Adirondack lowlands of northern New York. Between 15- and 40-Hz noise levels at this site are more than 10 dB less at 945-m depth than they are at the surface, and from 40 to 100 Hz the difference is more than 20 dB. In addition, time variability of the spectra is shown to be greater at the surface than at either 335- or 945-m depths. Part of the difference between the surface and subsurface noise variability may be related to wind-induced noise. Coherency measurements between orthogonal components of motion show high-frequency seismic noise is more highly organized at the surface than it is at depth. Coherency measurements between the same component of motion at different vertical offsets show a strong low-frequency coherence at least up to 945-m vertical offsets. As the vertical offset decreases, the frequency band of high coherence increases.

scholarly journals High‐frequency P‐wave seismic noise driven by ocean winds

2009 ◽  
Vol 36 (9) ◽  
Author(s):  
Jian Zhang ◽  
Peter Gerstoft ◽  
Peter M. Shearer
Keyword(s):  
High Frequency ◽  
Seismic Noise ◽  
P Wave ◽  
Ocean Winds

Evidence for the existence of locally-generated body waves in the short-period noise at the Large Aperture Seismic Array, Montana

1972 ◽  
Vol 62 (1) ◽  
pp. 13-29 ◽  
Author(s):  
H. M. Iyer ◽  
John H. Healy
Keyword(s):  
Statistical Analysis ◽  
Phase Velocity ◽  
High Frequency ◽  
Seismic Noise ◽  
Average Velocity ◽  
Low Frequency ◽  
Body Waves ◽  
Frequency Noise ◽  
High Frequency Noise ◽  
Short Period

Abstract The approximate hexagonal configuration of LASA subarrays enables their use as omnidirectional arrays. This property is used to study the phase velocity of short-period seismic noise at different frequencies. It is found that the noise in the low-frequency band consists mainly of surface waves traveling with average velocities in the range 3.0 to 3.5 km/sec. The high-frequency noise, in the band 0.45 to 1.0 Hz, has an average velocity of about 6.0 km/sec. It is quite likely that the high-frequency noise has the nature of locally-generated body waves. Statistical analysis of Pg velocities observed during a crustal refraction experiment at LASA lends support to this hypothesis.

scholarly journals Stim Salvage: Case Series Reporting on the Effectiveness of Spinal Cord Stimulation Salvage

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Patrick Paullus ◽  
Erika A Petersen
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Stimulation ◽  
High Frequency ◽  
New Technologies ◽  
Case Series ◽  
Low Frequency ◽  
Low Frequency Stimulation ◽  
Trial Outcomes ◽  
Frequency Stimulation ◽  
New System

Abstract INTRODUCTION Spinal cord stimulation (SCS) has been successfully used to treat chronic pain with improved levels of pain, decreased use of narcotic medications, and increased level of function. Nevertheless, for patients SCS benefit wares over time and maximal reprogramming may not achieve improvement. However, advancing technologies, such as burst and high-frequency modulation, offer stimulation which differs from the traditional low-frequency stimulation. For those with SCS already placed, these new technologies offer a possible avenue with which to salvage SCS loss of efficacy. In patients with the an ineffective system, a salvage trial with a new system can be performed. In these cases, their current generators are externalized and then, utilizing their current epidural array, the leads are connected to a new trial system. These patients return to the OR in about 1 wk time for either permanent implantation or removal of the remainder of their old system. The results of these salvage trials are presented. METHODS We reviewed serially treated patients with previously placed SCS who were taken to the operating room for a salvage trial. All patient had their SCS leads externalized and connected to a different system. Changes in VAS, functional status, the trial outcomes led to permanent placement were collected retrospectively. RESULTS Results of 15 patient who underwent SCS externalization trial between 2016 and 2019 are summarized. Trial failure rate, salvage SCS response rate, changes in VAS, and patient satisfaction with the new system are reviewed. Successful salvage was accomplished in 93%. CONCLUSION New stimulation paradigms such as burst and high frequency offer a new avenue of effective treatment for those with an ineffective SCS systems. When a patient's device is unable to deliver these paradigms, an IPG-externalization trial may be a low risk option for salvaging therapy.

Manifestation of earth deformation processes by high-frequency seismic noise characteristics

1990 ◽  
Vol 63 (3-4) ◽  
pp. 151-162 ◽  
Author(s):  
B.P. Diakonov ◽  
B.S. Karryev ◽  
O.B. Khavroshkin ◽  
A.V. Nikolaev ◽  
L.N. Rykunov ◽  
...  
Keyword(s):  
High Frequency ◽  
Seismic Noise ◽  
Noise Characteristics ◽  
Deformation Processes

Relationship between heating of the ground surface and high-frequency seismic noise

1992 ◽  
Vol 71 (1-2) ◽  
pp. 1-5 ◽  
Author(s):  
E.I. Gordeev ◽  
V.A. Saltykov ◽  
V.I. Sinitsin ◽  
V.N. Chebrov
Keyword(s):  
High Frequency ◽  
Seismic Noise ◽  
Ground Surface

scholarly journals The effect of 2020 COVID-19 lockdown measures on seismic noise recorded in Romania

Solid Earth ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 2351-2368
Author(s):  
Bogdan Grecu ◽  
Felix Borleanu ◽  
Alexandru Tiganescu ◽  
Natalia Poiata ◽  
Raluca Dinescu ◽  
...  
Keyword(s):  
Noise Reduction ◽  
High Frequency ◽  
Urban Areas ◽  
Seismic Noise ◽  
Human Mobility ◽  
Vertical Component ◽  
World Health ◽  
High Frequency Range ◽  
Frequency Range ◽  
40 Hz

Abstract. After the World Health Organization declared COVID-19 a pandemic in March 2020, Romania followed the example of many other countries and imposed a series of restrictive measures, including restricting people's mobility and closing social, cultural, and industrial activities to prevent the spread of the disease. In this study, we analyze continuous vertical component recordings from the stations of the Romanian Seismic Network – one of the largest networks in Europe, consisting of 148 stations – to explore the seismic noise variation associated with the reduced human mobility and activity due to the Romanian measures against COVID-19 in detail. We focused our investigation on four frequency bands – 2–8, 4–14, 15–25 and 25–40 Hz – and found that the largest reductions in seismic noise associated with the lockdown correspond to the high-frequency range of 15–40 Hz. We found that all the stations with large reductions in seismic noise (>∼  40 %) are located inside and near schools or in buildings, indicating that at these frequencies the drop is related to the drastic reduction of human activity in these edifices. In the lower-frequency range (2–8 and 4–14 Hz) the variability of the noise reduction among the stations is lower than in the high-frequency range, corresponding to about 35 % on average. This drop is due to reduced traffic during the lockdown, as most of the stations showing such changes in seismic noise in these bands are located within cities and near main or side streets. In addition to the noise reduction observed at stations located in populated areas, we also found seismic noise lockdown-related changes at several stations located far from urban areas, with movement of people in the vicinity of the station explaining the noise reductions.

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