Estimation of Direction of Wavefront Propagation and Slowness Using Time Domain Wavenumber Analysis in Small-Size Dense Seismic Arrays

2012 ◽  
Vol 479-481 ◽  
pp. 1186-1189
Author(s):  
Ping Liu ◽  
Hua Ma ◽  
Xue Wei Zhang ◽  
Xin Yu Sun ◽  
Fei Cao
Keyword(s):  
Time Domain ◽  
Seismic Array ◽  
Apparent Velocity ◽  
Seismic Signals ◽  
Analysis Method ◽  
Seismic Arrays ◽  
Wavefront Propagation ◽  
Pass Through ◽  
The Time Domain ◽  
Dense Seismic Array

The time domain wavenumber analysis method can directly delay and align signals before the superposition of signals in the time domain. In this paper, estimating the direction of wavefront propagation and the slowness for seismic signals which pass through the small-size dense seismic array is described in detail. The earthquake recorder sample adopted from US Geological Survey Parkfield Dense Seismograph Array (UPSAR array) of the U.S is used for analyzing. The results indicate that, the direction of wavefront propagation cannot be determined rashly only by the connecting line of the earthquake epicenter to the seismic array. The accuracy of the apparent velocity and the direction of wavefront propagation calculated using vertical seismic recorders is higher in West-East direction and in North-South direction.

Estimation of Direction of Wavefront Propagation and Apparent Velocity Using Earthquake Signals Recorded in Small-Size Dense Seismic Arrays

2012 ◽  
Vol 166-169 ◽  
pp. 2321-2325 ◽  
Author(s):  
Ping Liu ◽  
Hua Ma ◽  
Xue Wei Zhang ◽  
Xin Yu Sun ◽  
Fei Cao ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Correlation Method ◽  
Seismic Array ◽  
Geological Survey ◽  
Apparent Velocity ◽  
Seismic Signals ◽  
Seismic Arrays ◽  
Wavefront Propagation ◽  
Dense Seismic Array ◽  
The U.S

This paper presents that the cross-correlation method is used for estimating the direction of wavefront propagation and the apparent velocity for seismic signals in the small-size dense seismic array. The near earthquake signals samples adopted from US Geological Survey Parkfield Dense Seismograph Array (UPSAR array) of the U.S are used for analyzing. The results analyzed indicate that the wavefront propagation and the apparent velocity of near earthquake signals can be succinctly and accurately estimated by the method proposed in this paper.

scholarly journals A Method for the Analysis of Interference from DME to ATCRBS in the Time Domain

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 393 ◽  
Author(s):  
Guofeng Jiang ◽  
Yangyu Fan ◽  
Hongbo Yuan ◽  
Pengliang Yuan
Keyword(s):  
Time Domain ◽  
Traffic Control ◽  
Initial Time ◽  
Analysis Method ◽  
Operating Modes ◽  
The Monte Carlo Method ◽  
The Difference ◽  
The Time Domain ◽  
Overlap Method ◽  
Recurrence Frequency

Analysis of the coexistence of two or more types of equipment is increasingly important. However, at present studies on the analysis method in the time domain are scant. Therefore, the aim of this paper is to explore the characteristics of signals and relations between interfering and desired signals in the time domain. Based on the periodicity of a signal, this paper presents a Periodic Pulse Overlap Method (PPOM). Using PPOM to analyze the interference from Distance Measuring Equipment (DME) to Air Traffic Control Radar Beacon System (ATCRBS) in the time domain, we obtain almost the same result as that based on the Monte Carlo Method (MCM). Furthermore, we discover the measures to reduce or even avoid interference, such as changing the Pulse Recurrence Frequency (PRF), adjusting the difference of initial time, and switching the operating modes of the equipment.

Signal Acquisition and Analysis of Shaft Unbalance Vibration Test

2014 ◽  
Vol 945-949 ◽  
pp. 1090-1093
Author(s):  
Hai Peng Zhang ◽  
Hong Wu Chen ◽  
Bin Hu ◽  
Cheng Tian
Keyword(s):  
Fault Diagnosis ◽  
Time Domain ◽  
Time Domain Analysis ◽  
Rotating Machinery ◽  
Vibration Test ◽  
Signal Acquisition ◽  
Analysis Method ◽  
Characteristic Parameters ◽  
Test Platform ◽  
The Time Domain

This paper simulated the unbalance vibration conditions by the vibration test platform, measuring some common characteristic parameters of unbalance vibration fault diagnosis. This paper chose the time-domain analysis method, processing the characteristic parameters of the test, so as to achieve the purpose of vibration diagnosis. Through a large number of experimental data, this paper verified the feasibility and the effectiveness of the proposed approach to the unbalance fault diagnosis. The method proposed in this paper not only can be applied to unbalance fault diagnosis, but also can be promoted to apply to the fault diagnosis of other rotating machinery.

Shock Analysis and Design Method of Vibration Isolating System in the Time Domain

2005 ◽  
Author(s):  
Yinglong Zhao ◽  
Lin He ◽  
Zhiqiang Lv ◽  
Yu Wang
Keyword(s):  
Dynamic Analysis ◽  
Time Domain ◽  
Design Analysis ◽  
Analysis Method ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Protection Measures ◽  
Analysis And Design ◽  
Shock Protection ◽  
The Time Domain

Choosing the equipment with good shock-resistant performance and taking shock protection measures while designing the onboard settings, the safety of onboard settings can be assured when warships, especially submarine subjected to non-contact underwater explosion, that is, these means can be used to limit the rattlespace (i.e., the maximum displacement of the equipment relative to the base) and the peak acceleration experienced by the equipment. Using shock-resistant equipments is one of shock protection means. The shock-resistant performance of the shock-resistant equipments should be verified in the design phase of the equipments. The shock design analysis methods used before and now includes shock design number method (static g-method), dynamic analysis in the time domain and dynamic design analysis method (DDAM). The FEA (Finite Element Analysis) software, for example, MSC.NASTRAN®, can be used for shock design analysis of the shock-resistant equipments. MSC.NASTRAN are used for shock design analysis of floating raft vibration isolating equipment with dynamic analysis method in the time domain in this paper, and the analysis results are in agreement with the test results. The shock design analysis method used in this paper can be used to analyze the shock-resistant performance of onboard shock-resistant equipments.

Dynamics of Flexible Hose Riser Systems

1987 ◽  
Vol 109 (3) ◽  
pp. 244-248 ◽  
Author(s):  
H. Vogel ◽  
B. J. Natvig
Keyword(s):  
Time Domain ◽  
Analysis Method ◽  
Flexible Riser ◽  
Flexible Hose ◽  
3 Dimensional ◽  
Highly Effective ◽  
The Time Domain

The paper describes a highly effective method for computing the dynamics of the catenary-shaped suspension of flexible hose systems. The method accounts for a number of nonlinearities, it is 3-dimensional and it is performed in the time domain. The paper addresses the analysis method and demonstrates its effectiveness on a sample flexible riser analysis.

Investigating the crustal reflections of Taiwan from autocorrelation of seismic noise

2020 ◽  
Author(s):  
Zhuo-Kang Guan ◽  
Hao Kuo-Chen
Keyword(s):  
Receiver Function ◽  
Velocity Model ◽  
Seismic Array ◽  
Recording Time ◽  
Near Surface ◽  
Seismic Arrays ◽  
Short Period ◽  
Cross Correlations ◽  
Moho Depths ◽  
Dense Seismic Array

<p><span>Seismic interferometry is widely applied in various scales to reconstruct seismic signals for investigating Earth interior. The method of Phase Cross Correlation (PCC) takes less pre-processing and is more stable for retrieving of crustal signals than that of the conventional cross correlations by using amplitude information. In order to obtain the crustal reflectors in Taiwan, we applied auto-correlation with PCC to two independent datasets, (1) temporary seismic array in eastern Taiwan with 110 short period seismometers and (2) broadband seismic arrays (BATS and TAIGER) in Taiwan. As a result, the retrieved crustal reflectors, such as Moho reflectors, are stable with different recording time periods and instruments: temporal and spatial signal consistencies in the same site and neighborhood stations, respectively, and also high waveform similarities between short period and broadband seismometers.</span></p><p><span>Comparing the results with previous studies of velocity model and receiver function, the reflections at 10-12 seconds (roughly 30-40 km) are often observed in most of the results which are correlated to the Moho depths inferred from the receiver function and tomography studies. It is interesting to note that, besides the Moho reflections, some inter-crustal reflectors beneath the Central Range are revealed. The results show that the autocorrelation method has the potential to investigate some signals that are difficult to observe in the past by using other methods.</span></p><p><span>Another interesting observation from a dense seismic array in eastern Taiwan shows that the chimei fault serves as a sharp boundary to separate the reflectional signals into the northern and southern parts. In the southern part few reflections can be observed and also lack high frequency energies from autocorrelation comparing with those in the northern part. It implies that the distribution of ambient sources or near surface materials could influence the results. After examining the PCC’s feasibility and stability in this study, it is necessary to verify the reliability of results by understanding the source’s properties and local geological situations before interpretation.</span></p>

scholarly journals Automatic traveltime picking using instantaneous traveltime

Geophysics ◽  
2013 ◽  
Vol 78 (2) ◽  
pp. T53-T58 ◽  
Author(s):  
Christos Saragiotis ◽  
Tariq Alkhalifah ◽  
Sergey Fomel
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Field Data ◽  
Seismic Event ◽  
Seismic Signals ◽  
Recording Time ◽  
Time Frequency ◽  
Frequency Representation ◽  
Automatic Picking ◽  
The Time Domain

Event picking is used in many steps of seismic processing. We present an automatic event picking method that is based on a new attribute of seismic signals, instantaneous traveltime. The calculation of the instantaneous traveltime consists of two separate but interrelated stages. First, a trace is mapped onto the time-frequency domain. Then the time-frequency representation is mapped back onto the time domain by an appropriate operation. The computed instantaneous traveltime equals the recording time at those instances at which there is a seismic event, a feature that is used to pick the events. We analyzed the concept of the instantaneous traveltime and demonstrated the application of our automatic picking method on dynamite and Vibroseis field data.

Sign in / Sign up

Export Citation Format

Share Document