Earthquake-related gravity field changes at Beijing-Tangshan gravimetric network during 1987–1998

Li, Zhengxin; Li, Hui

doi:10.1007/s11200-009-0012-z

Cited by 12 publications

(7 citation statements)

References 13 publications

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“…Additionally, as the relation between earthquake and the timing of a detected LGFC, it is still too early to draw any conclusion. The facts reported in the paper should be considered as some new evidence supplemented to those already reported in the past (Li et al, 2009;Li et al, 2011).…”

Section: Discussionsupporting

confidence: 82%

“…From these 46 batch results, relative change of gravity field during the time of any two observational epochs can be derived with which the existence of a LGFC, being related to an underground mass migration, is checked. Quite the same as reported (Li et al, 2009), the LGFCs found are usually in pair, having almost the same shape and size but opposite in sign, and usually related to the timing of an earthquake in the area (Li et al, 2009;Li et al, 2011). Figure 3 shows two pairs of them: the LGFC(1)-LGFC(2) and the LGFC(3)-LGFC(4), of which the correlation coefficients are -0.67 and -0.89 respectively.…”

Section: Bttz Gravimetric Network and The Local Gravity Field Changesupporting

confidence: 67%

See 1 more Smart Citation

Some Mass Migration Underground Found in Beijing Area

Li¹,

Ping²,

Yang³

et al. 2014

GEP

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The relationship between the change of a local gravity field and the mass migration underground is discussed by means of using a point-source disturbed body as a substitute for the mass migration underground. Some significant local gravity field changes in Beijing area have been found, from which the three parameters of the disturbed bodies, location, depth and mass, have been derived successfully from the observations of a gravimetric network. In order to determine the depth of a body, a new approach is suggested in which the gravity change difference is used instead of the gravity change itself. The mass of a disturbing body has been estimated properly. Astronomical PZT is suggested for this kind of survey. The results provide us a picture of the underground mass migration with which the gravity changes on the ground surface may be interpreted in a better way. This additional information may be useful in seismological studies.

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Section: Discussionsupporting

confidence: 82%

Section: Bttz Gravimetric Network and The Local Gravity Field Changesupporting

confidence: 67%

Some Mass Migration Underground Found in Beijing Area

Li¹,

Ping²,

Yang³

et al. 2014

GEP

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“…Tangshan is a place where earthquakes happen frequently (Figure 1). The PLV, obtained by gravimetry technique, is shown in Figure 2, in which an annual term is also found [3] The PLV time series is very close to its regression straight line, thus its component on the line is considered as a main one with which a comparison is made with the earthquakes around. It appears that earthquakes (M > 4.0) usually happen near the time when the PLV begins its opposite moving (Figure 3) [3,4].…”

Section: Plv At Tangshan and Its Relation To The Earthquakes Around (mentioning

confidence: 79%

Plumb Line Variations (PLV) at China and Their Relation with Earthquakes and Underground Materials Changes

Yang

Ping²,

Li³

2013

OJG

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Plumb line variations (PLV) of points at Tangshan and Midu during 1985-1998 are determined by using the 46 batch repeated gravity observations of the Beijing-Tangshan network and 32 batch repeated gravity observations of the West-Yunan network. As for Tangshan region, relation between underground matter change (UMC) and the PLV on ground are discussed and approach of determining the UMC by a derived regional PLV is found. The UMC before and after earthquake(1995.10.05, Mb 5.0)in Tangshan region, as an example, is studied, giving the location and depth of the mass center of underground disturbing body as well as its mass quantity.

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“…Their results further showed the variations of the horizontal component (plumb line) of gravity field existed before earthquake, and the variations of horizontal component are the variations of plumb line. The anomalous variation of the plumb line may be a valuable premonitory phenomenon before earthquake [30]. In 1991, commission 19th (Rotation of the Earth) of IAU hoped Shanghai Astronomical Observatory can continue to collect these data in order to investigate the possibility of getting the long period variations of the plumb line.…”

Section: Significance and Research Progress Of Atlr Anomalies Before mentioning

confidence: 99%

Progress of research on anomalies of astronomical time and latitude observations before earthquake

2012

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This paper introduces the discovery of the phenomenon that short-term anomalous fluctuations appeared in residuals of astronomical time and latitude observations before earthquakes and the progress of related researches carried out for many years. The relations between the anomalous variations of time and latitude residuals of astronomical time and latitude instruments in different regions and the earthquakes around these instruments as well as the characteristics of residuals' anomalous variations are analyzed. The significance of the anomalous fluctuations in residuals of astronomical time and latitude caused by the anomalous variations of the local plumb line before earthquake and detecting the vertical variation with astronomical time and latitude observations as well as the importance of carrying out further researches are discoursed. The possibility that the phenomenon will become an effective short-term earthquakes precursor, the current situations and the problems to be solved, are discussed. Also we offer the proposals to develop new roboticized astrometric instruments with high-precision and set up test observation networks in earthquake-prone areas in order to do research in-depth, optimize methods of observing and extracting anomalous information for short-term earthquake prediction, and so on. Earthquake is one of the most serious natural disasters. A strong earthquake may create a large number of casualties and huge property losses. The earthquakes, which occurred in

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Earthquake-related gravity field changes at Beijing-Tangshan gravimetric network during 1987–1998

Cited by 12 publications

References 13 publications

Some Mass Migration Underground Found in Beijing Area

Some Mass Migration Underground Found in Beijing Area

Plumb Line Variations (PLV) at China and Their Relation with Earthquakes and Underground Materials Changes

Progress of research on anomalies of astronomical time and latitude observations before earthquake

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