COLLECTION AND ANALYSIS OF PACIFIC OCEAN‐BOTTOM SEISMIC DATA

Geophysics ◽  
1964 ◽  
Vol 29 (5) ◽  
pp. 745-771 ◽  
Author(s):  
William A. Schneider ◽  
Patrick J. Farrell ◽  
Ross E. Brannian
Keyword(s):  
Pacific Ocean ◽  
Seismic Data ◽  
Ambient Noise ◽  
Power Spectra ◽  
Simultaneous Recording ◽  
Distinct Advantage ◽  
Noise Power ◽  
Ocean Bottom ◽  
Detection And Identification ◽  
Land Station

A total of 500 hours of usable ocean‐bottom seismic data recorded on pressure and three components of velocity has been collected in three geographically separate areas of the Pacific Ocean at depths to 20,000 ft. These data are presently being analyzed to determine the extent to which monitoring seismic motion on the ocean floor can assist Project VELA UNIFORM goals of detection and identification of underground and underwater nuclear blasts. Analysis of three earthquakes and ambient noise recorded simultaneously on the ocean bottom and land reveals: 1. Ocean‐bottom signal‐to‐noise ratios are equal to or less than those seen at a comparative land station; 2. Ocean‐bottom signal and noise levels are higher than those obtained at the land station; and 3. Ocean‐bottom ambient noise power spectra increase in level towards the microseismic 6‐ to 8‐sec peak as do the land data. No strong directional ocean‐bottom noise components have been observed. Simultaneous recording of pressure and particle velocity affords the ocean‐bottom station a distinct advantage over its land counterpart, through exploitation of the relationships between pressure and vertical velocity which exist for various types of arrivals and modes.

To: “Collection and Analysis of Pacific Ocean‐Bottom Seismic Data,” by W. A. Schneider, P. J. Farrell, and R. E. Brannian (GEOPHYSICS, October 1964, p. 745–771)

Geophysics ◽  
1965 ◽  
Vol 30 (1) ◽  
pp. 145-145
Keyword(s):  
Pacific Ocean ◽  
Seismic Data ◽  
Ocean Bottom ◽  
Commanding Officer ◽  
Adverse Conditions ◽  
Ship Handling

In the article entitled “Collection and Analysis of Pacific Ocean‐Bottom Seismic Data,” by W. A. Schneider, P. J. Farrell, and R. E. Brannian (Geophysics, October 1964, p. 745–771), the authors failed to acknowledge the support of the USC&GSS SURVEYOR in acquiring the data at station locations north of latitude 52 between longitudes 176 and 178 west. The instrument drops and recoveries at these locations were often performed under adverse conditions and the rigging and ship‐handling skill of the Commanding Officer, Captain Fair J. Bryant, his officers, and crew deserves commendation and acknowledgment.

Object Detection Using an Ideal Observer Model

2020 ◽  
Vol 2020 (16) ◽  
pp. 41-1-41-7
Author(s):  
Orit Skorka ◽  
Paul J. Kane
Keyword(s):  
Object Detection ◽  
Matched Filter ◽  
Image Sensors ◽  
Ideal Observer ◽  
Noise Power ◽  
Relative Evaluation ◽  
Detection And Identification ◽  
Cross Correlation Analysis ◽  
Observer Model ◽  
The Ideal

Many of the metrics developed for informational imaging are useful in automotive imaging, since many of the tasks – for example, object detection and identification – are similar. This work discusses sensor characterization parameters for the Ideal Observer SNR model, and elaborates on the noise power spectrum. It presents cross-correlation analysis results for matched-filter detection of a tribar pattern in sets of resolution target images that were captured with three image sensors over a range of illumination levels. Lastly, the work compares the crosscorrelation data to predictions made by the Ideal Observer Model and demonstrates good agreement between the two methods on relative evaluation of detection capabilities.

Experimental and Theoretical Comparison of the Precision of Flame Atomic Absorption, Fluorescence, and Emission Measurements

1981 ◽  
Vol 35 (3) ◽  
pp. 317-324 ◽  
Author(s):  
N. W. Bower ◽  
J. D. Ingle
Keyword(s):  
Atomic Absorption ◽  
Flicker Noise ◽  
Power Spectra ◽  
Inner Filter Effect ◽  
Atomic Emission ◽  
Noise Power ◽  
Experimental Conditions ◽  
Noise Characteristics ◽  
Fluorescence Measurements ◽  
Flame Atomic Absorption

Theoretical equations and experimental evaluation procedures for the determination of the precision of flame atomic absorption, emission, and fluorescence measurements are presented. These procedures and noise power spectra are used to evaluate the precision and noise characteristics of atomic copper measurements with all three techniques under the same experimental conditions in an H2-air flame. At the detection limit, emission and fluorescence measurements are limited by background emission shot and flicker noise whereas absorption measurements are limited by flame transmission lamp flicker noise. Analyte flicker noise limits precision at higher analyte concentrations for all three techniques. Fluctutations in self-absorption and the inner filter effect are shown to contribute to the noise in atomic emission and fluorescence measurements.

Downward and upward continuation of 2-D seismic data to eliminate ocean bottom topography’s effect

2010 ◽  
Vol 7 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Xiang-Chun Wang ◽  
Chang-Liang Xia ◽  
Xue-Wei Liu
Keyword(s):  
Seismic Data ◽  
Ocean Bottom ◽  
Upward Continuation

Acquire Ocean Bottom Seismic Data and Time-Lapse Geochemistry Data Simultaneously to Identify Compartmentalization and Map Hydrocarbon Movement

2021 ◽  
Author(s):  
Rick Schrynemeeckers
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Time Lapse ◽  
Field Trials ◽  
Detection Methods ◽  
Ocean Bottom ◽  
Field Development ◽  
Dense Grid ◽  
Hydrocarbon Charge ◽  
Sweet Spots

Abstract Current offshore hydrocarbon detection methods employ vessels to collect cores along transects over structures defined by seismic imaging which are then analyzed by standard geochemical methods. Due to the cost of core collection, the sample density over these structures is often insufficient to map hydrocarbon accumulation boundaries. Traditional offshore geochemical methods cannot define reservoir sweet spots (i.e. areas of enhanced porosity, pressure, or net pay thickness) or measure light oil or gas condensate in the C7 – C15 carbon range. Thus, conventional geochemical methods are limited in their ability to help optimize offshore field development production. The capability to attach ultrasensitive geochemical modules to Ocean Bottom Seismic (OBS) nodes provides a new capability to the industry which allows these modules to be deployed in very dense grid patterns that provide extensive coverage both on structure and off structure. Thus, both high resolution seismic data and high-resolution hydrocarbon data can be captured simultaneously. Field trials were performed in offshore Ghana. The trial was not intended to duplicate normal field operations, but rather provide a pilot study to assess the viability of passive hydrocarbon modules to function properly in real world conditions in deep waters at elevated pressures. Water depth for the pilot survey ranged from 1500 – 1700 meters. Positive thermogenic signatures were detected in the Gabon samples. A baseline (i.e. non-thermogenic) signature was also detected. The results indicated the positive signatures were thermogenic and could easily be differentiated from baseline or non-thermogenic signatures. The ability to deploy geochemical modules with OBS nodes for reoccurring surveys in repetitive locations provides the ability to map the movement of hydrocarbons over time as well as discern depletion affects (i.e. time lapse geochemistry). The combined technologies will also be able to: Identify compartmentalization, maximize production and profitability by mapping reservoir sweet spots (i.e. areas of higher porosity, pressure, & hydrocarbon richness), rank prospects, reduce risk by identifying poor prospectivity areas, accurately map hydrocarbon charge in pre-salt sequences, augment seismic data in highly thrusted and faulted areas.

scholarly journals Noise masking method based on an effective ratio mask estimation in Gammatone channels

2018 ◽  
Vol 7 ◽  
Author(s):  
Feng Bao ◽  
Waleed H. Abdulla
Keyword(s):  
Signal To Noise Ratio ◽  
Estimation Method ◽  
Wiener Filter ◽  
Power Spectra ◽  
Auditory Scene Analysis ◽  
Accurate Estimation ◽  
Noise Power ◽  
Noise Masking ◽  
Time Frequency ◽  
Mask Estimation

In computational auditory scene analysis, the accurate estimation of binary mask or ratio mask plays a key role in noise masking. An inaccurate estimation often leads to some artifacts and temporal discontinuity in the synthesized speech. To overcome this problem, we propose a new ratio mask estimation method in terms of Wiener filtering in each Gammatone channel. In the reconstruction of Wiener filter, we utilize the relationship of the speech and noise power spectra in each Gammatone channel to build the objective function for the convex optimization of speech power. To improve the accuracy of estimation, the estimated ratio mask is further modified based on its adjacent time–frequency units, and then smoothed by interpolating with the estimated binary masks. The objective tests including the signal-to-noise ratio improvement, spectral distortion and intelligibility, and subjective listening test demonstrate the superiority of the proposed method compared with the reference methods.

Thermopower and 1/f Noise Measurements in Amorphous Silicon-Carbon Alloys

1995 ◽  
Vol 377 ◽  
Author(s):  
H. M. Dyalsingh ◽  
G. M. Khera ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Power Spectra ◽  
Carbon Films ◽  
Noise Power ◽  
Mobility Edge ◽  
Silicon Carbon ◽  
Noise Measurements ◽  
Noise Statistics ◽  
Hydrogenated Amorphous ◽  
Q Function

ABSTRACTThermopower, conductivity and 1/f noise measurements have been performed on a series of n-type doped hydrogenated amorphous silicon carbon films that are prepared with varying gas phase concentrations of CH4. The increased disorder at the mobility edge associated with alloying is characterized by the Q-function, which is obtained by combining thermopower and conductivity measurements, and is also reflected in the noise power spectra and noise statistics.

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