The strain seismograms of P- and S-waves of a local event recorded by four-gauge borehole strainmeter

Qiu, Zehua; Shun-liang, Chi; Wang, Zhenming; Carpenter, N. Seth; Tang, Lei; Guo, Yanping; Yang, Guang

doi:10.1007/s11589-015-0120-5

Cited by 7 publications

(7 citation statements)

References 16 publications

(11 reference statements)

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“…Unlike GTSM strainmeter such as the United States, which can produce high frequency data of 20 Hz, the data sampling rate of strainmeter in mainland China is minute sampling due to data storage and transmission technology. Using these minute data, scholars in mainland China have carried out a lot of research, including the tidal Variation and calibration technology (Qiu et al, 2015), abnormal changes of different earthquakes (Qiu et al, 2010;Liu et al, 2014), co-seismic strain steps (Gong et al, 2019;Li et al, 2020), free oscillation of the earth excited by large earthquakes (Tang et al, 2007;Tang et al, 2008;Qiu, 2017), and also studied and analyzed the influence of water level, air pressure, rainfall and other factors on borehole strain, and studied the data processing methods to identify and eliminate these influencing factors (Zhou et al, 2008;Zhang and Huang, 2011;Zhang et al, 2015). However, these studies are limited to longer period signals because of the low sampling rate.…”

Section: Introductionmentioning

confidence: 99%

“…Numerous studies have shown that the borehole strainmeter can be used for seismic wave observation (Byerly, 1926;Johnston et al, 1986;Borcherdt and Glassmoyer, 1989;Borcherdt et al, 2006;Johnston et al, 2006;Blum et al, 2010;Barbour and Agnew, 2012;Qiu et al, 2015;Barbour and Crowell, 2017;Canitano et al, 2017;Cao et al, 2018;Farghal et al, 2020;Barbour et al, 2021). This initially realized seismologists' expectations of strain seismographs (Benioff et al, 1961;Aki and Richards, 2002).…”

Section: Introductionmentioning

confidence: 99%

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The apparent focal depth, emergence angle, and take-off angle of seismic wave measured by YRY-4-type borehole strainmeter as one kind of strain seismograph

Tang

Qiu²,

Fan

et al. 2023

Front. Earth Sci.

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Introduction: In theory, the observation objects and principles of strain seismograph and traditional pendulum seismograph are different, and the characteristics of observed signals should also be dissimilar. The observation results of pendulum seismograph show that seismic waves in inhomogeneous media will undergo refraction, reflection, and attenuation. Then, what signal characteristics can be detected by strain seismograph is great significance for understanding and explaining the observation results.Methods: Using YRY-4 type four-gauge borehole strainmeter as one kind of strain seismograph to detect the strain tensor change of the plane seismic wave emitted from the surface, a five-site strain seismograph observation network was built in Shanxi Province, with continuous observation for 2 years at a sampling rate of 100 Hz. In this paper, two local events occurring in the area covered by the strain seismograph observation network are taken as examples. We systematically studied the characteristics of seismic wave signals recorded by strain seismographs at five sites, inverted for the focal depth of the two local earthquakes and the relationship between the wave velocity and the wave velocity gradient of the focal depth, and calculated the apparent focal depth, the emergence angle and the take-off angle of seismic waves.Results: These results show stable uniqueness and apparent regularity, especially since the inverted focal depths are basically consistent with the seismic solutions based on those traditional pendulum seismographs. The observations from this study show that the strain seismograph can be used as an effective supplement to the pendulum seismograph.Discussion: In the future, we will continue to study the rupture process and focal mechanism of moderate-strong earthquakes and teleseismic earthquakes by combining two kinds of observations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The apparent focal depth, emergence angle, and take-off angle of seismic wave measured by YRY-4-type borehole strainmeter as one kind of strain seismograph

Tang

Qiu²,

Fan

et al. 2023

Front. Earth Sci.

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“…Among them, borehole strainmeters, The associate editor coordinating the review of this manuscript and approving it for publication was Stefania Bonafoni . which detect crustal changes at high resolution on different time scales ranging from seconds to years [11], [12] provide an opportunity to investigate the preparation process prior to earthquakes [13]- [16], slow earthquakes [17], [18], seismic strain steps [19], [20], and volcanic eruptions [21].…”

Section: Introductionmentioning

confidence: 99%

Borehole Strain Observations Based on a State-Space Model and ApNe Analysis Associated With the 2013 Lushan Earthquake

Zhu

Hattori

et al. 2021

IEEE Access

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YRY-4 borehole strainmeters have been installed in Sichuan Province, China, since 2008, aimed at monitoring the crustal activities associated with earthquakes. In this study, data from six YRY-4 strainmeters at the southwestern endpoint of the Longmenshan fault zone were analysed, to study the relationship of tectonic strain changes with the 2013 Lushan earthquake. We developed a state-space model to remove the strain response due to air pressure, solid tides and the changes in the water level to preferentially isolate non-tectonic disturbances. Strain responses to each influencing factor were estimated using the environmental coefficients computed in the state-space model by an adaptive Kalman filter with measurement noise. The results were consistent with the expected response of the strainmeter systems. The corrected strain considered to originate from underground tectonics provides new insights into the changes in the pre-earthquake strain. Approximate negentropy (ApNe) and b value were introduced to quantify the probability distribution of the corrected borehole strain and compared with the local seismic activities. The nearest station and two further stations, almost simultaneously recorded short-term ApNe anomalies six to four months before the earthquake. The anomalous region also had a correspondingly low b value. Moreover, the anomaly acceleration rates of each station were dependent on the epicentral distances. Further comparison with the strain of random periods illustrated the significance of the extracted anomalies. Our results indicate that the corrected strain may contain seismogenic information and reflect the accelerated strain accumulation of focal areas before the earthquake.INDEX TERMS State-space model, Kalman filter, ApNe, b values, short-term strain anomalies, Lushan earthquake.

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“…The observations have many advantages such as high resolution, broad band, and topographic-feature-independence, amongst others. High-resolution borehole strainmeters allow for the detection of subtle strain variations to study slow earthquakes [Sacks et al, 1978[Sacks et al, , 1981Linde et al,1996;Liu et al, 2009], seismic strain steps [McGarr et al,1982;Asai et al,2005;Qiu et al, 2003Qiu et al, , 2004Qiu et al, , 2015Barbour et al, 2012], and volcanic eruptions [Voight et al, 2006;Hautmann et al, 2013;Sturkell et al, 2013]. 1High-resolution borehole records also provide the opportunity to investigate strain changes prior to earthquakes.…”

Section: Introductionmentioning

confidence: 99%

The characteristics analysis of strain variation associated with Wenchuan earthquake using principal component analysis

Zhu

Chi

et al. 2020

Annals of Geophysics

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Borehole strainmeters that are installed deeply into bedrock are capable of recording both continuous stress and strain measurements, and have consequently become an important tool for monitoring crustal deformation. A YRY-4 borehole strainmeter installed at the Guza Station recorded anomalous changes in borehole strain data preceding the Wenchuan earthquake on May 12, 2008 (UTC) (=8.0). We apply principal component analysis (PCA) to analyze borehole strain data from the Guza Station. The first principal component eigenvalues and eigenvectors are calculated. The fitted results of the cumulative number of anomalous eigenvalues demonstrate that an acceleration occurred approximately 4 months before the earthquake (from January 2008). The results of the combined eigenvalue and eigenvector analyses show that the spatial distribution of eigenvectors and accelerated occurrence of eigenvalue anomalies represents the stress evolution characteristics of the fault from a steady state to a sub-instability state in rock experiments. We tentatively infer that this process may also be linked to the preparation phase of a large earthquake.

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The strain seismograms of P- and S-waves of a local event recorded by four-gauge borehole strainmeter

Cited by 7 publications

References 16 publications

The apparent focal depth, emergence angle, and take-off angle of seismic wave measured by YRY-4-type borehole strainmeter as one kind of strain seismograph

The apparent focal depth, emergence angle, and take-off angle of seismic wave measured by YRY-4-type borehole strainmeter as one kind of strain seismograph

Borehole Strain Observations Based on a State-Space Model and ApNe Analysis Associated With the 2013 Lushan Earthquake

The characteristics analysis of strain variation associated with Wenchuan earthquake using principal component analysis

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