According to different testing purposes, methods and available environmental conditions, the seismograph testing can be divided into laboratory and on-site testing, respectively. The testing of the seismograph's k...According to different testing purposes, methods and available environmental conditions, the seismograph testing can be divided into laboratory and on-site testing, respectively. The testing of the seismograph's key parameters and other concerning technical specifications are well described in guide documents(China Earthquake Administration, 2017). This includes seismometer sensitivity, linearity and clip levels based on the shake table test, as well as the seismometer natural period, damping constant based on electrical calibration(Wang Guangfu,1986; Ple?inger A.,1993) and instrumental self-noise collocation estimation(Holcomb L.G., 1989; Sleeman R. et al., 2006). However, with the development of seismic observation technology, many new requirements for the performance evaluation of seismographs have been put forward, and new testing items and methods have emerged.展开更多
We introduce in this paper a method to calculate response spectra of earthquake ground motion from seismograms of Type 513 seismograph. The seismograms of two horizontal components of the M s 7.1 earthquake, an a...We introduce in this paper a method to calculate response spectra of earthquake ground motion from seismograms of Type 513 seismograph. The seismograms of two horizontal components of the M s 7.1 earthquake, an aftershock of 1976 M S=7.8 Tangshan earthquake, recorded by type 513 seismograph in Taian station are used as an example. After curve digitization, arc shape curve correction, equal distance interpolation and instrument response correction, the absolute acceleration response spectra, relative velocity response spectra and relative displacement response spectra of different damping ratios in the period range of T ≤10 s are calculated in frequency domain.展开更多
The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for m...The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for measuring ice flow velocity include the use of stakes, snow pits and on-site geodetic GPS and remote sensing measurement methods. Geodetic GPS measurements have high accuracy, but geodetic GPS monitoring points only sparsely cover the Antarctic ice sheets. Moreover, the resolution and accuracy of ice flow velocities based on remote sensing measurements are low. Although the accuracy of the location data recorded by the navigation-grade GPS receivers embedded in short-period seismographs is not as good as that of geodetic GPS,the ice flow velocity can be accurately measured by these navigation-grade GPS data collected over a sufficiently long period. In this paper, navigation-grade GPS location data obtained by passive seismic observations during the 36 th Chinese National Antarctic Research Expedition were used to accurately track the movement characteristics of the ice sheet in the Larsemann Hills of East Antarctica and the Taishan Station area. The results showed that the ice sheet in the two study areas is basically moving northwestward with an average ice flow velocity of approximately 1 m mon-1. The results in the Taishan Station area are basically consistent with the geodetic GPS results, indicating that it is feasible to use the embedded GPS location data from shortperiod seismographs to track the movement characteristics of ice sheets. The ice flow characteristics in the Larsemann Hills are more complex. The measured ice flow velocities in the Larsemann Hills with a resolution of 200 m help to understand its characteristics. In summary, the ice flow velocities derived from GPS location data are of great significance for studying ice sheet dynamics and glacier mass balance and for evaluating the systematic errors caused by ice sheet movements in seismic imaging.展开更多
The South Yellow Sea basin is filled with Mesozoic-Cenozoic continental sediments overlying pre-Palaeozoic and Mesozoic-Palaeozoic marine sediments.Conventional multi-channel seismic data cannot describe the velocity ...The South Yellow Sea basin is filled with Mesozoic-Cenozoic continental sediments overlying pre-Palaeozoic and Mesozoic-Palaeozoic marine sediments.Conventional multi-channel seismic data cannot describe the velocity structure of the marine residual basin in detail,leading to the lack of a deeper understanding of the distribution and lithology owing to strong energy shielding on the top interface of marine sediments.In this study,we present seismic tomography data from ocean bottom seismographs that describe the NEE-trending velocity distributions of the basin.The results indicate that strong velocity variations occur at shallow crustal levels.Horizontal velocity bodies show good correlation with surface geological features,and multi-layer features exist in the vertical velocity framework(depth:0–10 km).The analyses of the velocity model,gravity data,magnetic data,multichannel seismic profiles,and drilling data showed that high-velocity anomalies(>6.5 km/s)of small(thickness:1–2 km)and large(thickness:>5 km)scales were caused by igneous complexes in the multi-layer structure,which were active during the Palaeogene.Possible locations of good Mesozoic and Palaeozoic marine strata are limited to the Central Uplift and the western part of the Northern Depression along the wide-angle ocean bottom seismograph array.Following the Indosinian movement,a strong compression existed in the Northern Depression during the extensional phase that caused the formation of folds in the middle of the survey line.This study is useful for reconstructing the regional tectonic evolution and delineating the distribution of the marine residual basin in the South Yellow Sea basin.展开更多
On August 26, 2019, the deep-hole integrated geophysical observation system of the long-term observatory of the Chinese Continental Scientific Drilling project (CCSD) was successfully placed into the deep-hole and rec...On August 26, 2019, the deep-hole integrated geophysical observation system of the long-term observatory of the Chinese Continental Scientific Drilling project (CCSD) was successfully placed into the deep-hole and received signals in real time (Fig. 1). The deep-hole geophysical observation system was installed to expected design depth: two sets of seismographs and three sets of geotherms were placed at the main hole of 1498 m, 2367 m, 3006 m and 3499 m respectively. The temperature of the deepest installation position is up to 98 ℃, the pressure is up to 35 MPa, and the minimum inner diameter is only 175 mm. It is the deepest deep-hole geophysical observation system in China (Fig. 2).展开更多
Impacts of airblast and vibrations arise from blasting, a dangerous activity if not designed and performed to standard. This paper evaluates airblast and ground vibration levels and its potential impact on the neighbo...Impacts of airblast and vibrations arise from blasting, a dangerous activity if not designed and performed to standard. This paper evaluates airblast and ground vibration levels and its potential impact on the neighbouring communities. Two calibrated seismographs were used to monitor potential airblast and ground vibration generated from the blast at Chimiwungo Pit. The blast complied with the set limits for infrastructures and slopes monitoring. Vibrations recorded from the trial shot PPV were predicted at 2.46 mm/s and Airblast of 10 mm/s with a maximum of 134 dB at the mine boundary, all remained well below accepted industry standards and guidelines. The airblast and ground vibration levels monitored and recorded were considered to be normal for surface blasting operations and had no negative impact on the nearby township of Manyama.展开更多
This paper presents an overview of the magnitude determination of the November 14, 2001 west of Kunlun Mountain Pass (KMP) earthquake at the juncture of Xinjiang and Qinghai, northwestern China. Comparisons are made a...This paper presents an overview of the magnitude determination of the November 14, 2001 west of Kunlun Mountain Pass (KMP) earthquake at the juncture of Xinjiang and Qinghai, northwestern China. Comparisons are made among surface wave magnitudes determined by China National Digital Seismograph Network (CNDSN), National Earthquake Information Center (NEIC) of US Geological Survey (USGS) and moment magnitudes de- termined by different institutions in China and abroad. The result shows that different institutions yield different surface wave magnitudes, as different data and calculation formulae are used in magnitude determination. The magnitude of the earthquake in China′s Rapid Earthquake Information Release was given as MS=8.1; measurement given in the formally edited and published Observation Report of China Digital Seismograph Network is MS=8.2; and magnitude determined by USGS/NEIC is MS=8.0. Soon after the occurrence of the KMP earthquake, Harvard University (Harvard), USGS/NEIC, Earthquake Research Institute, Tokyo University (ERI), Center for Analysis and Prediction, China Earthquake Administration (APCEA) and Institute of Geophysics, China Earthquake Ad- ministration (IGCEA) gave the moment magnitude MW as 7.8, 7.7, 7.7, 7.6 and 7.5, respectively, based on data from Global Seismograph Network (GSN), CNDSN and China Digital Seismograph Network (CDSN). These measurements, with an average value of MW=7.7, are close to each other. As moment magnitude is a physical quantity measuring the absolute size of an earthquake and has obvious advantages over conventional magnitude scale, and is the preferred magnitude of the international seismological community. It is concluded that the KMP earthquake is an earthquake with unsaturated surface wave magnitude with moment magnitude MW=7.7 and sur- face wave magnitude MS=8.0.展开更多
Development of China Digital Seismological Observational Systems during 1996~2000 and the Capital Circle Area Seismograph Network during 1999~2001 are introduced, and the station distributions, instruments used, main ...Development of China Digital Seismological Observational Systems during 1996~2000 and the Capital Circle Area Seismograph Network during 1999~2001 are introduced, and the station distributions, instruments used, main tasks of National Digital Seismograph Network, Regional Digital Seismograph Network and Portable Digital Seismograph Network are introduced chiefly.展开更多
The 0S2-0S54 spheroidal modes of Earth＇s free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seism...The 0S2-0S54 spheroidal modes of Earth＇s free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seismograph Network （CDSN）. We compare these spheroidal modes with theoretical free oscillation spectra calculated from the Preliminary Reference Earth Model （PREM） and find a coincidence between their periods. Spectral splitting phenomenon is observed obviously in 0S2, 0S3, 0S4, 2S1 and 1S2 free oscillation modes. What is most noticeable is that the oscillation mode 2S1 is reported for the second time （the first time by Rosat et al） without any data stacking. We simulated the split singlet of 0S2 mode on seven CDSN stations based on general focal mechanism and seismic moment of the earthquake. The result shows that seismic moment of the earthquake can reach 10^23 N.m. We also find that the recording of Earth＇s free oscillations carries abundant information of source mechanism and earthquake location, which is applicable to the detailed study of source rupture parameters.展开更多
In order to eliminate chaotic oscillation of electromechanical seismograph system, the complex dynamic characteristics of the four-dimensional nonlinear equations of electromechanical seismograph system were analyzed....In order to eliminate chaotic oscillation of electromechanical seismograph system, the complex dynamic characteristics of the four-dimensional nonlinear equations of electromechanical seismograph system were analyzed. Sliding mode method was applied to stabilize the chaotic orbits of the electromechanical seismograph system to arbitrary chosen fixed points and periodic orbits precisely, and MATLAB simulations were presented to confirm the validity of the controller. The results show that using sliding mode method can make the system track target orbit strictly and smoothly with short transition time, and its insensitivity to noise disturbances is shown. It also provides reference for relevant chaos control in relevant system.展开更多
The main purpose of this research is to estimate the structural analysis and hydrocarbon potential of Miano Block by using seismic and well log techniques. Miano area hosts a number of gas fields with structural and s...The main purpose of this research is to estimate the structural analysis and hydrocarbon potential of Miano Block by using seismic and well log techniques. Miano area hosts a number of gas fields with structural and stratigraphic traps. The area is located in Central Indus Basin which is a part of an extensional regime exhibiting normal faulting due to the split of the Indian Plate firstly from Africa and then from Madagascar and Seychelles. Miano area recognized as a proven petroleum province which has complex tectonic history of Cretaceous extensional and overprints of Tertiary strike-slip tectonics. The area has prospect with accumulation of hydrocarbons in structural and stratigraphic traps including pinchouts. NW-SE oriented Khairpur and Mari Highs are main structural features with impact on the fault system. The sands of Lower Goru of Lower Cretaceous age are acting as a reservoir in the area. The area has great potential of hydrocarbons for which more exploratory wells are required to be drilled with better insight of structural and stratigraphic traps.展开更多
Criminal law involves crucial rights of the public,including property rights,political rights,freedom,and even life.As a result,on the one hand,any change to the rule by criminal law may have a significant impact on p...Criminal law involves crucial rights of the public,including property rights,political rights,freedom,and even life.As a result,on the one hand,any change to the rule by criminal law may have a significant impact on people’s lives;on the other hand,any change to the rule by criminal law is a highly sensitive issue.In view of these points,the rule by criminal law is often referred to as the seismograph for the protection of human rights,indicating the utmost importance of rule by criminal law展开更多
基金sponsored by the Department of Earthquake Monitoring and Prediction,China Earthquake Administration
文摘According to different testing purposes, methods and available environmental conditions, the seismograph testing can be divided into laboratory and on-site testing, respectively. The testing of the seismograph's key parameters and other concerning technical specifications are well described in guide documents(China Earthquake Administration, 2017). This includes seismometer sensitivity, linearity and clip levels based on the shake table test, as well as the seismometer natural period, damping constant based on electrical calibration(Wang Guangfu,1986; Ple?inger A.,1993) and instrumental self-noise collocation estimation(Holcomb L.G., 1989; Sleeman R. et al., 2006). However, with the development of seismic observation technology, many new requirements for the performance evaluation of seismographs have been put forward, and new testing items and methods have emerged.
文摘We introduce in this paper a method to calculate response spectra of earthquake ground motion from seismograms of Type 513 seismograph. The seismograms of two horizontal components of the M s 7.1 earthquake, an aftershock of 1976 M S=7.8 Tangshan earthquake, recorded by type 513 seismograph in Taian station are used as an example. After curve digitization, arc shape curve correction, equal distance interpolation and instrument response correction, the absolute acceleration response spectra, relative velocity response spectra and relative displacement response spectra of different damping ratios in the period range of T ≤10 s are calculated in frequency domain.
基金supported by the National Natural Science Foundation of China(Grant Nos.41974044,U1901602,41790465,and 41876227)the Science and Technology Project of Shenzhen(Grant No.KQTD2017081011725321)。
文摘The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for measuring ice flow velocity include the use of stakes, snow pits and on-site geodetic GPS and remote sensing measurement methods. Geodetic GPS measurements have high accuracy, but geodetic GPS monitoring points only sparsely cover the Antarctic ice sheets. Moreover, the resolution and accuracy of ice flow velocities based on remote sensing measurements are low. Although the accuracy of the location data recorded by the navigation-grade GPS receivers embedded in short-period seismographs is not as good as that of geodetic GPS,the ice flow velocity can be accurately measured by these navigation-grade GPS data collected over a sufficiently long period. In this paper, navigation-grade GPS location data obtained by passive seismic observations during the 36 th Chinese National Antarctic Research Expedition were used to accurately track the movement characteristics of the ice sheet in the Larsemann Hills of East Antarctica and the Taishan Station area. The results showed that the ice sheet in the two study areas is basically moving northwestward with an average ice flow velocity of approximately 1 m mon-1. The results in the Taishan Station area are basically consistent with the geodetic GPS results, indicating that it is feasible to use the embedded GPS location data from shortperiod seismographs to track the movement characteristics of ice sheets. The ice flow characteristics in the Larsemann Hills are more complex. The measured ice flow velocities in the Larsemann Hills with a resolution of 200 m help to understand its characteristics. In summary, the ice flow velocities derived from GPS location data are of great significance for studying ice sheet dynamics and glacier mass balance and for evaluating the systematic errors caused by ice sheet movements in seismic imaging.
基金The National Natural Science Foundation of China under contract No.41806048the Open Fund of the Hubei Key Laboratory of Marine Geological Resources under contract No.MGR202009+2 种基金the Fund from the Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resource,Institute of Geology,Chinese Academy of Geological Sciences under contract No.J1901-16the Aoshan Science and Technology Innovation Project of Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2015ASKJ03-Seabed Resourcesthe Fund from the Korea Institute of Ocean Science and Technology(KIOST)under contract No.PE99741.
文摘The South Yellow Sea basin is filled with Mesozoic-Cenozoic continental sediments overlying pre-Palaeozoic and Mesozoic-Palaeozoic marine sediments.Conventional multi-channel seismic data cannot describe the velocity structure of the marine residual basin in detail,leading to the lack of a deeper understanding of the distribution and lithology owing to strong energy shielding on the top interface of marine sediments.In this study,we present seismic tomography data from ocean bottom seismographs that describe the NEE-trending velocity distributions of the basin.The results indicate that strong velocity variations occur at shallow crustal levels.Horizontal velocity bodies show good correlation with surface geological features,and multi-layer features exist in the vertical velocity framework(depth:0–10 km).The analyses of the velocity model,gravity data,magnetic data,multichannel seismic profiles,and drilling data showed that high-velocity anomalies(>6.5 km/s)of small(thickness:1–2 km)and large(thickness:>5 km)scales were caused by igneous complexes in the multi-layer structure,which were active during the Palaeogene.Possible locations of good Mesozoic and Palaeozoic marine strata are limited to the Central Uplift and the western part of the Northern Depression along the wide-angle ocean bottom seismograph array.Following the Indosinian movement,a strong compression existed in the Northern Depression during the extensional phase that caused the formation of folds in the middle of the survey line.This study is useful for reconstructing the regional tectonic evolution and delineating the distribution of the marine residual basin in the South Yellow Sea basin.
文摘On August 26, 2019, the deep-hole integrated geophysical observation system of the long-term observatory of the Chinese Continental Scientific Drilling project (CCSD) was successfully placed into the deep-hole and received signals in real time (Fig. 1). The deep-hole geophysical observation system was installed to expected design depth: two sets of seismographs and three sets of geotherms were placed at the main hole of 1498 m, 2367 m, 3006 m and 3499 m respectively. The temperature of the deepest installation position is up to 98 ℃, the pressure is up to 35 MPa, and the minimum inner diameter is only 175 mm. It is the deepest deep-hole geophysical observation system in China (Fig. 2).
文摘Impacts of airblast and vibrations arise from blasting, a dangerous activity if not designed and performed to standard. This paper evaluates airblast and ground vibration levels and its potential impact on the neighbouring communities. Two calibrated seismographs were used to monitor potential airblast and ground vibration generated from the blast at Chimiwungo Pit. The blast complied with the set limits for infrastructures and slopes monitoring. Vibrations recorded from the trial shot PPV were predicted at 2.46 mm/s and Airblast of 10 mm/s with a maximum of 134 dB at the mine boundary, all remained well below accepted industry standards and guidelines. The airblast and ground vibration levels monitored and recorded were considered to be normal for surface blasting operations and had no negative impact on the nearby township of Manyama.
基金National High Technology Research and Development Programme of China (2001CB711005).
文摘This paper presents an overview of the magnitude determination of the November 14, 2001 west of Kunlun Mountain Pass (KMP) earthquake at the juncture of Xinjiang and Qinghai, northwestern China. Comparisons are made among surface wave magnitudes determined by China National Digital Seismograph Network (CNDSN), National Earthquake Information Center (NEIC) of US Geological Survey (USGS) and moment magnitudes de- termined by different institutions in China and abroad. The result shows that different institutions yield different surface wave magnitudes, as different data and calculation formulae are used in magnitude determination. The magnitude of the earthquake in China′s Rapid Earthquake Information Release was given as MS=8.1; measurement given in the formally edited and published Observation Report of China Digital Seismograph Network is MS=8.2; and magnitude determined by USGS/NEIC is MS=8.0. Soon after the occurrence of the KMP earthquake, Harvard University (Harvard), USGS/NEIC, Earthquake Research Institute, Tokyo University (ERI), Center for Analysis and Prediction, China Earthquake Administration (APCEA) and Institute of Geophysics, China Earthquake Ad- ministration (IGCEA) gave the moment magnitude MW as 7.8, 7.7, 7.7, 7.6 and 7.5, respectively, based on data from Global Seismograph Network (GSN), CNDSN and China Digital Seismograph Network (CDSN). These measurements, with an average value of MW=7.7, are close to each other. As moment magnitude is a physical quantity measuring the absolute size of an earthquake and has obvious advantages over conventional magnitude scale, and is the preferred magnitude of the international seismological community. It is concluded that the KMP earthquake is an earthquake with unsaturated surface wave magnitude with moment magnitude MW=7.7 and sur- face wave magnitude MS=8.0.
文摘Development of China Digital Seismological Observational Systems during 1996~2000 and the Capital Circle Area Seismograph Network during 1999~2001 are introduced, and the station distributions, instruments used, main tasks of National Digital Seismograph Network, Regional Digital Seismograph Network and Portable Digital Seismograph Network are introduced chiefly.
基金State Key Fundamental Research Development Plan Project (2001CB711005) National Natural Science Founda-tion of China (40374012)
文摘The 0S2-0S54 spheroidal modes of Earth＇s free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seismograph Network （CDSN）. We compare these spheroidal modes with theoretical free oscillation spectra calculated from the Preliminary Reference Earth Model （PREM） and find a coincidence between their periods. Spectral splitting phenomenon is observed obviously in 0S2, 0S3, 0S4, 2S1 and 1S2 free oscillation modes. What is most noticeable is that the oscillation mode 2S1 is reported for the second time （the first time by Rosat et al） without any data stacking. We simulated the split singlet of 0S2 mode on seven CDSN stations based on general focal mechanism and seismic moment of the earthquake. The result shows that seismic moment of the earthquake can reach 10^23 N.m. We also find that the recording of Earth＇s free oscillations carries abundant information of source mechanism and earthquake location, which is applicable to the detailed study of source rupture parameters.
基金the Independent Research Project of State Key Laboratory of Power Transmission Equipment & System Security and New Technology,China ( No. 2007DA10512711205)
文摘In order to eliminate chaotic oscillation of electromechanical seismograph system, the complex dynamic characteristics of the four-dimensional nonlinear equations of electromechanical seismograph system were analyzed. Sliding mode method was applied to stabilize the chaotic orbits of the electromechanical seismograph system to arbitrary chosen fixed points and periodic orbits precisely, and MATLAB simulations were presented to confirm the validity of the controller. The results show that using sliding mode method can make the system track target orbit strictly and smoothly with short transition time, and its insensitivity to noise disturbances is shown. It also provides reference for relevant chaos control in relevant system.
文摘The main purpose of this research is to estimate the structural analysis and hydrocarbon potential of Miano Block by using seismic and well log techniques. Miano area hosts a number of gas fields with structural and stratigraphic traps. The area is located in Central Indus Basin which is a part of an extensional regime exhibiting normal faulting due to the split of the Indian Plate firstly from Africa and then from Madagascar and Seychelles. Miano area recognized as a proven petroleum province which has complex tectonic history of Cretaceous extensional and overprints of Tertiary strike-slip tectonics. The area has prospect with accumulation of hydrocarbons in structural and stratigraphic traps including pinchouts. NW-SE oriented Khairpur and Mari Highs are main structural features with impact on the fault system. The sands of Lower Goru of Lower Cretaceous age are acting as a reservoir in the area. The area has great potential of hydrocarbons for which more exploratory wells are required to be drilled with better insight of structural and stratigraphic traps.
文摘Criminal law involves crucial rights of the public,including property rights,political rights,freedom,and even life.As a result,on the one hand,any change to the rule by criminal law may have a significant impact on people’s lives;on the other hand,any change to the rule by criminal law is a highly sensitive issue.In view of these points,the rule by criminal law is often referred to as the seismograph for the protection of human rights,indicating the utmost importance of rule by criminal law
