Modern geodetic technologies such as high-precision ground gravity measurements,satellite gravity measurements,the global navigation satellite system,remote sensing methods,etc.provide rich observation data for monito...Modern geodetic technologies such as high-precision ground gravity measurements,satellite gravity measurements,the global navigation satellite system,remote sensing methods,etc.provide rich observation data for monitoring various geodynamic processes of the global Earth and its surface.The 19th International Symposium on Geodynamics and Earth Tides brought together scientific researchers from 26 countries around the world,shared the application of various measurements in different geoscience issues,covering Earth tidal deformation,oceanic and atmospheric loading effects,earthquake cycle,hydrology,Earth rotation changes,etc.,and provided a precious exchange platform for global peers.展开更多
In this paper, through the nonlinear response of rock strain and stress, we have analized the physical mechanism of loading and unloading response ratio of the well level to the earth tides,the respouse of an aquife...In this paper, through the nonlinear response of rock strain and stress, we have analized the physical mechanism of loading and unloading response ratio of the well level to the earth tides,the respouse of an aquifer of confined well to bulk strain tide and showed two methods of the calculation of loading and unloading response ratio of the well level to the earth tides. We took the example of the Yu 01 well, which is near the epicenter of Heze M S 5.9 earthquake, calculated the response rate and loading and unloading response ratio of two kinds of the earth tides of it. The response rate and response ratio before the earthquake had the variation of increase.展开更多
The 18th International Symposium on Geodynamics and Earth Tides 2016 covered phenomena that generate temporal variations in geodetic and geophysical observations. In calculating the stress field for Earth tides, the o...The 18th International Symposium on Geodynamics and Earth Tides 2016 covered phenomena that generate temporal variations in geodetic and geophysical observations. In calculating the stress field for Earth tides, the observed geodetic response is used for defining the Earth＇s theology, the Earth internal structure, ＇Earth rotation parameters, and the functioning of the sophisticated instrumentation mounted on Earth and satellites. The instrumentation capable of observing Earth tides, measures changes generated by lithospheric plate movements, as the earthquake cycle and volcanism. Hydrology, tem- perature, and pressure, either of natural or anthropogenic origin, affect the high precision observations, and therefore must be included in this study-realm.展开更多
t Taking the M2 wave as calibration signals, we extract the phase shifts of the water level relative to the Earth tide in the Zhouzhi well by utilizing the cross-correlation function. And we further obtain the apparen...t Taking the M2 wave as calibration signals, we extract the phase shifts of the water level relative to the Earth tide in the Zhouzhi well by utilizing the cross-correlation function. And we further obtain the apparent permeability variation in the aquifer of the Zhouzhi well in 2008. Comparison with the commonly used tidal analysis software Baytap-G shows that phase shifts obtained by cross-correlation function are more stable. The resulting apparent permeability of the Zhouzhi well aquifer fluctuates with time, indicating it is a dynamically controlled parameter. The 2008 Wenchuan earthquake caused the apparent permeability increasing drastically, which is interpreted as the combination effects of effective stress changes and the barriers removing in the flow channel due to seismic wave pressure pulse. After the Wenchuan earthquake, the effective stress began to recover and the impurities deposited gradually, causing the apparent permeability to decrease a month later and almost recover to the pre-earthquake level in six months.展开更多
Zero drift and solid Earth tide corrections to static relative gravirnetric data cannot be ignored. In this paper, a new principal component analysis （PCA） algorithm is presented to extract the zero drift and the so...Zero drift and solid Earth tide corrections to static relative gravirnetric data cannot be ignored. In this paper, a new principal component analysis （PCA） algorithm is presented to extract the zero drift and the solid Earth tide, as signals, from static relative gravimetric data assuming that the components contained in the relative gravimetric data are uncorrelated. Static relative gravity observations from Aug. 15 to Aug. 23, 2014 are used as statistical variables to separate the signal and noise with PCA to obtain desired signals. The results of the linear drift extracted by PCA are consistent with those calculated by the least squares linear fitting, and the differences only reach to 10-2μGal/day order of magnitude. Furthermore, PCA is used to estimate the solid Earth tide from the relative gravimetric data corrected by the zero drift. The statistical results are consistent with the results derived from the solid Earth tide correction provided by the internal software of the CG-5 gravimeter （SCINTREX Limited Ontario Canada）. The statistical results of the differences between the two methods are both less than 8 ,Gal, and the RMSs for 9 days are all less than 5 μGal.展开更多
Previous studies suggest that tidal friction gives rise to the secular deceleration of the Earth rotation by a quantity of about 2.25 ms/cy. Here we just consider additional contributions to the secular Earth rotation...Previous studies suggest that tidal friction gives rise to the secular deceleration of the Earth rotation by a quantity of about 2.25 ms/cy. Here we just consider additional contributions to the secular Earth rotation deceleration. Atmospheric solar semi-diurnal tide has a small amplitude and certain amount of phase lead. This periodic global air-mass excess distribution exerts a quasi-constant torque to accelerate the Earth＇s spin rotation. Using an updated atmospheric tide model, we re-estimate the amounts of this atmospheric acceleration torque and corresponding energy input, of which the associated change rate in LOD（length of day） is-0.1 ms/cy. In another aspect, evidences from space-geodesy and sea level rise observations suggest that Earth expands at a rate of 0.35 mm/yr in recent decades, which gives rise to the increase of LOD at rate of 1.0 ms/cy. Hence, if the previous estimate due to the tidal friction is correct, the secular Earth rotation deceleration due to tidal friction and Earth expansion should be 3.15 ms/cy.展开更多
This paper studies the imminent anomalies observed by the Sacks volume strainmeter in Erzhangying station and Tiantanghe station before 80 earthquakes with Ms≥ 7. 0 which took place from January 2011 to April 2014 al...This paper studies the imminent anomalies observed by the Sacks volume strainmeter in Erzhangying station and Tiantanghe station before 80 earthquakes with Ms≥ 7. 0 which took place from January 2011 to April 2014 all over the world. Then, preconditions for anomaly identification are put forward for complex earthquake cases. Statistical results show that volume strain observation has a better earthquake reflecting ability for earthquakes with magnitudes larger than 7. 0 and epicentral distance within 8000kin. In addition, these results also reflect that the volume strain observation can better reflect precursory anomalies of such earthquakes. Based on categorization and description of those anomalies, we divide the anomalies into three types, that is, earth tide distortion type, abrupt change type and slow earthquake type. Furthermore, the paper makes a statistical analysis of these types and preliminarily discusses their mechanical properties as well. According to research, volume strain anomaly has an indicative significance to future strong earthquakes in the world.展开更多
The relation between the local mean lunar time τ of earthquake occurrence and their fault trends is studied in this paper. The local mean lunar times τ of 53 earthquakes in 24 groups are calculated. Because ...The relation between the local mean lunar time τ of earthquake occurrence and their fault trends is studied in this paper. The local mean lunar times τ of 53 earthquakes in 24 groups are calculated. Because the tidal generation force arisen by the moon is a cyclic function of about 12 hours 25 minutes in the main, the two tidal generation forces anywhere in the earth arising by the moon are equal in general when the moon lies to the two sites of 180° interval of local mean lunar time. Based on this phenomenon the values Δ τ of τ 1- τ 2 or τ 1-τ 2±180° of two earthquakes occurring repetitiously in the same place are also calculated. The calculated results show that if the fault trends of the two earthquakes in the same place is near, the Δ τ is usually smaller and if the fault trends of the two ones is not near, the Δ τ is usually larger and the distribution of the local mean lunar time τ of earthquakes in different places is dispersive even if fault trends of these earthquakes are near, and the τ does not concentrate on the lower and upper transit of the moon. The above phenomena clear up that the triggering earthquake of earth solid tide arisen by the moon is relative with the fault trends of earthquakes and we ought to think over the difference of environmental conditions of earthquake preparation of each seismogenic zone and can not make statistics to earthquakes in different places when we study the relation between the solid earth tide arisen by the moon and earthquakes.展开更多
The water level in a deep well instantly responds to the earth’s tide and atmospheric pressure, and varies accordingly, not only in terms of amplitude but also in the phase lag. Therefore, phase lag correction is use...The water level in a deep well instantly responds to the earth’s tide and atmospheric pressure, and varies accordingly, not only in terms of amplitude but also in the phase lag. Therefore, phase lag correction is used in analyzing digital groundwater observation data in eastern China. Calculation results presented by the authors in this paper show that the correction method is effective in the identification of anomalous changes for short-term seismic precursors. The correction method can also be applied to the processing of observed deformation and tilt data.展开更多
This paper investigates the correlation between tidal stress and earthquakes for periods ranging from hours to months in the limited zone of the Palu region(Central Sulawesi,Indonesia).Through Schuster and binomial te...This paper investigates the correlation between tidal stress and earthquakes for periods ranging from hours to months in the limited zone of the Palu region(Central Sulawesi,Indonesia).Through Schuster and binomial tests,we examined the relation between the seismicity(time density of seismic events)and tidal potential arising from the Moon and Sun,using all tidal components simultaneously and focusing on the estimation of specific terms.The results show significant correlations between the seismicity and tidal potential for S2(0.5 d)and O1(1.075 d)tidal components in the case of solely isolated earthquake events,particularly for shallow earthquakes.Meanwhile,there is a strong relationship between aftershocks and tidal components larger than the Mf period(13.661 d).Finally,the analysis of the temporal variation of the earthquake-tide relation reveals an optimal correlation for about six years before the 2018 great Palu earthquake.The correlation becomes insignificant afterwards.展开更多
An unidentified geophysical event is first reported in this paper. It was recorded with Lacoste & Romberg earth tide gravity meter (ET 21) at Chinese Antarctic Zhongshan Station.
In order to solve the problems in the observation with the SS-Y extensometer, such as background noise and discontinuity of earth tide curve, this paper proposed to improve the stability of the instrument and the smoo...In order to solve the problems in the observation with the SS-Y extensometer, such as background noise and discontinuity of earth tide curve, this paper proposed to improve the stability of the instrument and the smoothness of the earth tide curve by improving the baseline structure of the instrument. In this study, a new φ20*1.2 invar tube was introduced in replacement of the existing φ6 invar rod as the baseline of the instrument and compared with the existing φ6 invar rod on the instrument’s linearity,sensitivity and other indexes. Firstly, the SS-Y extensometers using φ6 invar rod and cp20*1.2 invar tube were tested. Test results were then calculated, and accuracy errors of the instruments based on the two baselines were obtained. Finally, their accuracy errors and earth tide curves were compared. Results showed that, compared with the extensometer based on the existing φ6 invar rod, the extensometer based on the new φ20*1.2 invar tube was superior in performance, with linearity error reducing to 0.495% from 0.937%, sensitivity increasing to 68.65 mV/μm from 65.46 mV/μm, and earth tide curve growing more stable and continuous.展开更多
Water temperature observation in wells,as a precursor observation project in China,aims to capture stress-strain information during the preparation of earthquakes. The study of the water temperature tidal effect has i...Water temperature observation in wells,as a precursor observation project in China,aims to capture stress-strain information during the preparation of earthquakes. The study of the water temperature tidal effect has important significance,for water temperature tidal effect is both a reflection of stress-strain in crust and an interference factor of precursor observations. With a view of thermal conditions in artesian wells,the paper holds that there are two mechanisms for interpreting tidally induced water temperature changes in artesian wells. Namely,thermal conduction mechanisms and thermal convection mechanism. The paper then derives the quantitative relationship between water temperature and tidal volumetric strain changes in an ideal artesian well. Finally,the water temperature tidal effect in the Benxi artesian well is analyzed. The results show that the water temperature tidal effect in Benxi well is the result of joint action of thermal conduction mechanism and thermal convection mechanism,in which thermal conduction mechanism plays a leading role.展开更多
Tidal phase of water temperature in Qixian well,Shanxi Province is ahead of water level,which is different from the normal tidal relationship between water temperature and water level. Observation curves of this pheno...Tidal phase of water temperature in Qixian well,Shanxi Province is ahead of water level,which is different from the normal tidal relationship between water temperature and water level. Observation curves of this phenomenon are introduced in this paper,and co-seismic response data of water temperature and water level are used to check the thermometer time system,confirming that this phenomenon is true. Using the harmonic analysis method,variations of time difference between water temperature and water level for the M2 wave are worked out,which indicates that this phenomenon exists during the whole observation. According to the variations of phase lags for water temperature and water level,and the survey of observation conditions, it is considered that the abnormal phenomenon may be related to inadequate passage of water caused by a well blockage at the depth where the water temperature probe was set.展开更多
In the paper,a particle surface-simplex search（PSSS） is designed based on particle surface-simplex and particle surface-simplex neighborhood.Using PSSS and an evolutionary strategy of multi-states swarm,a surface-si...In the paper,a particle surface-simplex search（PSSS） is designed based on particle surface-simplex and particle surface-simplex neighborhood.Using PSSS and an evolutionary strategy of multi-states swarm,a surface-simplex swarm evolution（SSSE） algorithm for numerical optimization is proposed.In the experiments,SSSE is applied to solve 17 benchmark problems and compared with the other intelligent optimization algorithms.In the application,SSSE is used to analyze the three intrinsic independent components of gravity earth tide.The results demonstrate that SSSE can accurately find optima or close-to-optimal solutions of the complex functions with high-dimension.The performance of SSSE is stable and efficient.展开更多
基金Major Program of the National Natural Science Foundation of China(42192535).
文摘Modern geodetic technologies such as high-precision ground gravity measurements,satellite gravity measurements,the global navigation satellite system,remote sensing methods,etc.provide rich observation data for monitoring various geodynamic processes of the global Earth and its surface.The 19th International Symposium on Geodynamics and Earth Tides brought together scientific researchers from 26 countries around the world,shared the application of various measurements in different geoscience issues,covering Earth tidal deformation,oceanic and atmospheric loading effects,earthquake cycle,hydrology,Earth rotation changes,etc.,and provided a precious exchange platform for global peers.
文摘In this paper, through the nonlinear response of rock strain and stress, we have analized the physical mechanism of loading and unloading response ratio of the well level to the earth tides,the respouse of an aquifer of confined well to bulk strain tide and showed two methods of the calculation of loading and unloading response ratio of the well level to the earth tides. We took the example of the Yu 01 well, which is near the epicenter of Heze M S 5.9 earthquake, calculated the response rate and loading and unloading response ratio of two kinds of the earth tides of it. The response rate and response ratio before the earthquake had the variation of increase.
基金scientifically supported by the IAG:Commission 3,the IAG Sub-commission 3.1 and International Geodynamics and Earth Tide ServiceThe University of Trieste and the sponsors of the Symposium,namely the OGS(Istituto Nazionale di Oceanografia e di Geofisica Sperimentale)+8 种基金the Dipartimento di Fisica E. Caianiello,University of Salernothe Department of Mathematics and Geosciences of the University of TriesteLeica Geosystems S.P.A.International Association of Geodesy (3 IAG Travel Awards for young scientists)the European Geosciences Union(support to 8 young scientists)the Rector Maurizio Fermeglia of the University of Triestethe President Maria Cristina Pedicchio of OGSInstitute of oceanography and applied geophysicsthrough the contribution of the Italian Space Agency in the frame of the project "MOCASS" (-Mass Observation with Cold Atom Sensors in Space
文摘The 18th International Symposium on Geodynamics and Earth Tides 2016 covered phenomena that generate temporal variations in geodetic and geophysical observations. In calculating the stress field for Earth tides, the observed geodetic response is used for defining the Earth＇s theology, the Earth internal structure, ＇Earth rotation parameters, and the functioning of the sophisticated instrumentation mounted on Earth and satellites. The instrumentation capable of observing Earth tides, measures changes generated by lithospheric plate movements, as the earthquake cycle and volcanism. Hydrology, tem- perature, and pressure, either of natural or anthropogenic origin, affect the high precision observations, and therefore must be included in this study-realm.
基金supported by the National Natural Science Foundation of China under grant Nos.40674024 and 41040036
文摘t Taking the M2 wave as calibration signals, we extract the phase shifts of the water level relative to the Earth tide in the Zhouzhi well by utilizing the cross-correlation function. And we further obtain the apparent permeability variation in the aquifer of the Zhouzhi well in 2008. Comparison with the commonly used tidal analysis software Baytap-G shows that phase shifts obtained by cross-correlation function are more stable. The resulting apparent permeability of the Zhouzhi well aquifer fluctuates with time, indicating it is a dynamically controlled parameter. The 2008 Wenchuan earthquake caused the apparent permeability increasing drastically, which is interpreted as the combination effects of effective stress changes and the barriers removing in the flow channel due to seismic wave pressure pulse. After the Wenchuan earthquake, the effective stress began to recover and the impurities deposited gradually, causing the apparent permeability to decrease a month later and almost recover to the pre-earthquake level in six months.
基金supported by the National Natural Science Foundation of China(41374009)the Public Benefit Scientific Research Project of China(201412001)+1 种基金the Shandong Natural Science Foundation of China(ZR2013DM009)the SDUST Research Fund(2014TDJH101)
文摘Zero drift and solid Earth tide corrections to static relative gravirnetric data cannot be ignored. In this paper, a new principal component analysis （PCA） algorithm is presented to extract the zero drift and the solid Earth tide, as signals, from static relative gravimetric data assuming that the components contained in the relative gravimetric data are uncorrelated. Static relative gravity observations from Aug. 15 to Aug. 23, 2014 are used as statistical variables to separate the signal and noise with PCA to obtain desired signals. The results of the linear drift extracted by PCA are consistent with those calculated by the least squares linear fitting, and the differences only reach to 10-2μGal/day order of magnitude. Furthermore, PCA is used to estimate the solid Earth tide from the relative gravimetric data corrected by the zero drift. The statistical results are consistent with the results derived from the solid Earth tide correction provided by the internal software of the CG-5 gravimeter （SCINTREX Limited Ontario Canada）. The statistical results of the differences between the two methods are both less than 8 ,Gal, and the RMSs for 9 days are all less than 5 μGal.
基金partly supported by National 973 Project China(2013CB733305)NSFC(41174011,41210006,41504019)supported by a fund from Korea Astronomy and Space Science Institute(2016 Space Geodesy Project about Atmospheric/Ocean Tidal Effects)
文摘Previous studies suggest that tidal friction gives rise to the secular deceleration of the Earth rotation by a quantity of about 2.25 ms/cy. Here we just consider additional contributions to the secular Earth rotation deceleration. Atmospheric solar semi-diurnal tide has a small amplitude and certain amount of phase lead. This periodic global air-mass excess distribution exerts a quasi-constant torque to accelerate the Earth＇s spin rotation. Using an updated atmospheric tide model, we re-estimate the amounts of this atmospheric acceleration torque and corresponding energy input, of which the associated change rate in LOD（length of day） is-0.1 ms/cy. In another aspect, evidences from space-geodesy and sea level rise observations suggest that Earth expands at a rate of 0.35 mm/yr in recent decades, which gives rise to the increase of LOD at rate of 1.0 ms/cy. Hence, if the previous estimate due to the tidal friction is correct, the secular Earth rotation deceleration due to tidal friction and Earth expansion should be 3.15 ms/cy.
基金Combined project of monitoring,prediction and research of China Earthquake Administration entitled "Statistical study on the earthquake cases of imminent anomaly in Sacks volume strain measurements(154201)""Special Fund for Basic Scientific Research of Institute of Earthquake Science,CEA(2012IES010202)""Research on Regional Tectonic Stability for the Dateng Gorge Water Conservancy Hub Project Site(880456)"
文摘This paper studies the imminent anomalies observed by the Sacks volume strainmeter in Erzhangying station and Tiantanghe station before 80 earthquakes with Ms≥ 7. 0 which took place from January 2011 to April 2014 all over the world. Then, preconditions for anomaly identification are put forward for complex earthquake cases. Statistical results show that volume strain observation has a better earthquake reflecting ability for earthquakes with magnitudes larger than 7. 0 and epicentral distance within 8000kin. In addition, these results also reflect that the volume strain observation can better reflect precursory anomalies of such earthquakes. Based on categorization and description of those anomalies, we divide the anomalies into three types, that is, earth tide distortion type, abrupt change type and slow earthquake type. Furthermore, the paper makes a statistical analysis of these types and preliminarily discusses their mechanical properties as well. According to research, volume strain anomaly has an indicative significance to future strong earthquakes in the world.
文摘The relation between the local mean lunar time τ of earthquake occurrence and their fault trends is studied in this paper. The local mean lunar times τ of 53 earthquakes in 24 groups are calculated. Because the tidal generation force arisen by the moon is a cyclic function of about 12 hours 25 minutes in the main, the two tidal generation forces anywhere in the earth arising by the moon are equal in general when the moon lies to the two sites of 180° interval of local mean lunar time. Based on this phenomenon the values Δ τ of τ 1- τ 2 or τ 1-τ 2±180° of two earthquakes occurring repetitiously in the same place are also calculated. The calculated results show that if the fault trends of the two earthquakes in the same place is near, the Δ τ is usually smaller and if the fault trends of the two ones is not near, the Δ τ is usually larger and the distribution of the local mean lunar time τ of earthquakes in different places is dispersive even if fault trends of these earthquakes are near, and the τ does not concentrate on the lower and upper transit of the moon. The above phenomena clear up that the triggering earthquake of earth solid tide arisen by the moon is relative with the fault trends of earthquakes and we ought to think over the difference of environmental conditions of earthquake preparation of each seismogenic zone and can not make statistics to earthquakes in different places when we study the relation between the solid earth tide arisen by the moon and earthquakes.
基金This project was sponsored by the Science and Technology Development Program(031060107) ,Shandong Province .
文摘The water level in a deep well instantly responds to the earth’s tide and atmospheric pressure, and varies accordingly, not only in terms of amplitude but also in the phase lag. Therefore, phase lag correction is used in analyzing digital groundwater observation data in eastern China. Calculation results presented by the authors in this paper show that the correction method is effective in the identification of anomalous changes for short-term seismic precursors. The correction method can also be applied to the processing of observed deformation and tilt data.
文摘This paper investigates the correlation between tidal stress and earthquakes for periods ranging from hours to months in the limited zone of the Palu region(Central Sulawesi,Indonesia).Through Schuster and binomial tests,we examined the relation between the seismicity(time density of seismic events)and tidal potential arising from the Moon and Sun,using all tidal components simultaneously and focusing on the estimation of specific terms.The results show significant correlations between the seismicity and tidal potential for S2(0.5 d)and O1(1.075 d)tidal components in the case of solely isolated earthquake events,particularly for shallow earthquakes.Meanwhile,there is a strong relationship between aftershocks and tidal components larger than the Mf period(13.661 d).Finally,the analysis of the temporal variation of the earthquake-tide relation reveals an optimal correlation for about six years before the 2018 great Palu earthquake.The correlation becomes insignificant afterwards.
文摘An unidentified geophysical event is first reported in this paper. It was recorded with Lacoste & Romberg earth tide gravity meter (ET 21) at Chinese Antarctic Zhongshan Station.
基金supported by the National Natural Science Foundation(41274037)
文摘In order to solve the problems in the observation with the SS-Y extensometer, such as background noise and discontinuity of earth tide curve, this paper proposed to improve the stability of the instrument and the smoothness of the earth tide curve by improving the baseline structure of the instrument. In this study, a new φ20*1.2 invar tube was introduced in replacement of the existing φ6 invar rod as the baseline of the instrument and compared with the existing φ6 invar rod on the instrument’s linearity,sensitivity and other indexes. Firstly, the SS-Y extensometers using φ6 invar rod and cp20*1.2 invar tube were tested. Test results were then calculated, and accuracy errors of the instruments based on the two baselines were obtained. Finally, their accuracy errors and earth tide curves were compared. Results showed that, compared with the extensometer based on the existing φ6 invar rod, the extensometer based on the new φ20*1.2 invar tube was superior in performance, with linearity error reducing to 0.495% from 0.937%, sensitivity increasing to 68.65 mV/μm from 65.46 mV/μm, and earth tide curve growing more stable and continuous.
基金sponsored by the"Subsurface Fluid Observational Specification Research Program"(2060302-8-19),China
文摘Water temperature observation in wells,as a precursor observation project in China,aims to capture stress-strain information during the preparation of earthquakes. The study of the water temperature tidal effect has important significance,for water temperature tidal effect is both a reflection of stress-strain in crust and an interference factor of precursor observations. With a view of thermal conditions in artesian wells,the paper holds that there are two mechanisms for interpreting tidally induced water temperature changes in artesian wells. Namely,thermal conduction mechanisms and thermal convection mechanism. The paper then derives the quantitative relationship between water temperature and tidal volumetric strain changes in an ideal artesian well. Finally,the water temperature tidal effect in the Benxi artesian well is analyzed. The results show that the water temperature tidal effect in Benxi well is the result of joint action of thermal conduction mechanism and thermal convection mechanism,in which thermal conduction mechanism plays a leading role.
基金funded by the 12th "Five-year Plan" of National Science and Technology Sponsored Project,China(2012BAK19B02-04)
文摘Tidal phase of water temperature in Qixian well,Shanxi Province is ahead of water level,which is different from the normal tidal relationship between water temperature and water level. Observation curves of this phenomenon are introduced in this paper,and co-seismic response data of water temperature and water level are used to check the thermometer time system,confirming that this phenomenon is true. Using the harmonic analysis method,variations of time difference between water temperature and water level for the M2 wave are worked out,which indicates that this phenomenon exists during the whole observation. According to the variations of phase lags for water temperature and water level,and the survey of observation conditions, it is considered that the abnormal phenomenon may be related to inadequate passage of water caused by a well blockage at the depth where the water temperature probe was set.
基金Supported by the National Natural Science Foundation of China(41364002)
文摘In the paper,a particle surface-simplex search（PSSS） is designed based on particle surface-simplex and particle surface-simplex neighborhood.Using PSSS and an evolutionary strategy of multi-states swarm,a surface-simplex swarm evolution（SSSE） algorithm for numerical optimization is proposed.In the experiments,SSSE is applied to solve 17 benchmark problems and compared with the other intelligent optimization algorithms.In the application,SSSE is used to analyze the three intrinsic independent components of gravity earth tide.The results demonstrate that SSSE can accurately find optima or close-to-optimal solutions of the complex functions with high-dimension.The performance of SSSE is stable and efficient.
