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[1]WANG Liwei,LI Li,YANG Wei,et al.Signal Characteristics of Low Frequency Vibroseis and Its Application to High Precision Dynamic Monitoring[J].Journal of Seismological Research,2021,44(04):622-634.

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Signal Characteristics of Low Frequency Vibroseis and Its Application to High Precision Dynamic Monitoring

Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume: 44 Number of periods: 2021 04 Page number: 622-634 Column: Public date: 2021-11-10

Title:: Signal Characteristics of Low Frequency Vibroseis and Its Application to High Precision Dynamic Monitoring

Author(s):: WANG Liwei¹; 2; 3; LI Li¹; YANG Wei¹; WANG Baoshan¹; 4; HUANG Liufang²; 3; (1.Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;2.CEA Key Laboratory of Earthquake Monitoring and Disaster Mitigation Technology,Guangdong Earthquake Agency,Guangzhou 510070,Guangdong,China;3.Guangdong Provincial Key Laboratory of Earthquake Early Warning and Safety Diagnosis of Major Projects,Guangdong Earthquake Agency,Guangzhou 510070,Guangdong,China;4.School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,Anhui,China)

Keywords:: low frequency vibroseis; cluster analysis; deconvolution; phase-weighted stack; velocity changes; high precision dynamic monitoring

CLC:: P315.3

DOI:: -

Abstract:: The low frequency vibroseis can generate broad band,low energy density and high repeatable signals with frequencies as low as 1.5 Hz,which is particularly suitable for high resolution exploration and regional seismological research.In order to evaluate its signal characteristics and feasibility in high precision dynamic monitoring,we conduct a field experiment on KZ28LF low frequency vibroseis.We found that it can stably generate low frequency signals in 1.5～12 Hz in upsweeping and pseudorandom sweeping mode,the near field energy is strong in 9～12 Hz and weak in 1.5～9 Hz,and the waveform correlation coefficient is greater than 0.95,accounting for 81% and 63% respectively,but it is still difficult to put sufficient energy into the ground in low frequency band.The signal repeatability is low and the harmonic energy is strong in single frequency excitation mode.Both the coherent and deconvolution method can successfully compress the source wavelet and restore the interpretable record,but the repeatability and signal-to-noise ratio of coherent method is higher,and the deconvolution result can keep a higher fidelity in phase and amplitude.After phase-weighted stacking,the max recording offsets can reach more than 20 km,and the monitoring precision of seismic velocity changes can reach up to ～10^-4.The result can provide a reference for high resolution monitoring of active fault zones,earthquake nucleation process and land slip.

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Last Update: 2021-11-10