NETWORK STUDIES-SIGNAL CHARACTERISTICS

The report presents an initial study of signal characteristics and coherent signal processing at the network level. Topics investigated include signal similarity, depth-phase detection and recognition, separation and location of events overlapping in time and space, and methods for real-time network...

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Bibliographic Details
Main Authors: Benno, Stephen A, Johnson, William A, Strange, Peter L, Bonner, James A
Other Authors: TEXAS INSTRUMENTS INC DALLAS SCIENCE SERVICE DIV
Format: Text
Language:English
Published: 1968
Subjects:
Seismology
Acoustics
*SEISMOLOGICAL STATIONS
BACKGROUND
CORRELATION TECHNIQUES
DATA PROCESSING
DENSITY
DETECTION
EARTHQUAKES
ELECTROMAGNETIC WAVE FILTERS
NETWORKS
NOISE
NUCLEAR EXPLOSIONS
PHASED ARRAYS
POWER SPECTRA
SAMPLING
SEISMOMETERS
SIGNAL TO NOISE RATIO
SIGNALS
SPECTRUM SIGNATURES
BEAM STEERING
SEISMIC NOISE
VELA UNIFORM
Kamchatka
Online Access:http://www.dtic.mil/docs/citations/AD0830463
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0830463
Description
Summary:The report presents an initial study of signal characteristics and coherent signal processing at the network level. Topics investigated include signal similarity, depth-phase detection and recognition, separation and location of events overlapping in time and space, and methods for real-time network processing and data presentation. Large variations in signal waveform and signal-to-noise ratio (SNR) are observed across the network. Interstation coefficients of correlation for a relatively simple Kamchatka event vary from 0. 54 to 0.96, with the higher correlation found for stations on the eastern North American continent. Levinson equalization filtering does not appear particularly effective at the network level in terms of improved correlation coefficients or SNR. Depth-phase detection at the network level is not materially better than for selected stations, but recognition appears more reliable than for general station results. Experiments show that overlapping events of differing magnitudes and separated in epicenter by as little as 1 degree can be resolved by network beamsteer and integrate techniques. Signal-enhancement procedures implemented primarily to determine the extent of signal attenuation caused by signal dissimilarity across the network indicate less than 3-db reduction in signal energy across the signal passband.

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