The ocean accounts for approximately 71%of the total area of the Earth.Whether it is studying the shape of the Earth itself through geodesy or the future development of earth system science,strengthening the construct...The ocean accounts for approximately 71%of the total area of the Earth.Whether it is studying the shape of the Earth itself through geodesy or the future development of earth system science,strengthening the construction of ocean geodesy disciplines and innovating ocean geodetic observation technologies have evident theoretical and practical significance.In recent years,the discipline of ocean geodesy in China has been continuously developing and growing,and notable breakthroughs have been made in ocean satellite geodesy and seafloor geodetic observation technology.Research on ocean geodetic observation models and algorithms has also made great progress.展开更多
The geodesy discipline has been evolving and constantly intersecting and merging with other disciplines in the last 50 years,due to the continuous progress of geodetic observation techniques and expansion of applicati...The geodesy discipline has been evolving and constantly intersecting and merging with other disciplines in the last 50 years,due to the continuous progress of geodetic observation techniques and expansion of application fields.This paper first introduces the development and roles of geodesy and its formation.Secondly,the development status of geodesy discipline is analyzed from the progress of observation techniques and cross-discipline formation is analyzed from the expansion of application fields.Furthermore,the development trend of geodesy is stated from the perspective of national requirements and scientific developments.Finally,the sub-disciplines for geodesy are suggested at the present stage,based on the requirements of the National Natural Science Foundation of China and development status of geodesy itself,which can provide references for topic selection and fund application of geodetic scientific research.展开更多
To overcome the high cost of learning,non-visual operation,and cumbersome steps of fine-tuning map elements in Generic Mapping Tools(GMT)and other geoscience mapping softwares,we present the Tectonic Geodesy Applicati...To overcome the high cost of learning,non-visual operation,and cumbersome steps of fine-tuning map elements in Generic Mapping Tools(GMT)and other geoscience mapping softwares,we present the Tectonic Geodesy Application(TGA),a user-friendly 64-bit tectonic geodesy mapping software based on the secondary development interface of the open source geographic information system QGIS.In this paper,we detailly introduce the architecture and function modules of our software,and highlight the functions of rendering and map decoration through four cases:the geologic map of Papua New Guinea,the seismicity in China and surrounding regions,the seismicity and crustal deformation of the Tibetan Plateau and the coseismic deformation of the 2017 Jiuzhaigou earthquake in China.Compared with GMT,the tectonic geodesy mapping software we developed has the advantages of simple operation,low learning cost and user-friendly interface.展开更多
Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world. Its aim is to promote a combinatio...Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world. Its aim is to promote a combination between Geodesy and Geodynamics, deepen the application of Geodesy in the field of Geoscience and quicken worldwide fellows’ understanding on scientific research activity in China. It mainly展开更多
"Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opport..."Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opportunity for participants from Canada and from around the world to come together and share their science and culture.2019 marks the 100th anniversary of IUGG;we will look back on the accomplishments of the previous century of Earth and space science research,and forward to the next century of scientific advancement.Join us for a host of scientific activities,including special public lectures,keynote Union lectures and a wide variety of themed sessions.展开更多
UNAVCO supports geoscience research at 113 US academic Member institutions,and another 104 Associate Member institutions include international universities,laboratories,observatories,academies of science,and a museum....UNAVCO supports geoscience research at 113 US academic Member institutions,and another 104 Associate Member institutions include international universities,laboratories,observatories,academies of science,and a museum.This diverse membership shares UNAVCO’s purpose at home and abroad,giving UNAVCO global reach in advancing geodesy.Since the mid-1980s,modern geodesy has evolved into a cutting-edge,multi-faceted toolbox with remarkably diverse research and real-world applications,including studies and observation or forecasting of solid-Earth hazards,the dynamics of the atmosphere,climate,near-Earth space environment,and of key environmental parameters such as water storage,soil moisture,and seaand lake-level changes.UNAVCO operates facilities on behalf of the U.S.National Science Foundation to support investigators who use geodetic tools across all of these Earth and atmospheric domains.UNAVCO has built a number of large dense regional networks of GPS stations,including the Earth Scope Plate Boundary Observatory in North America,the COCONetCaribbean network,TLALOCNet in Mexico,GNET in Greenland,and ANET in Antarctica.Going forward,UNAVCO plans to federate the Plate Boundary Observatory(USA),TLALOCNet(Mexico),and COCONet(Caribbean)GPS networks as the Network of the Americas,with upgrades to state-of-the-art,multi-sensor,multi-GNSS observations.While UNAVCO community scientists actively engage in using space and terrestrial geodetic techniques to study geodynamics at all scales,this proliferation of continuous networks is the basis for a suite of recent contributions that focus on improved daily positioning to sense Earth’s elastic response and other perturbations to loading by atmospheric and surface water,oceans,and ice.Day-to-day and sub-daily variations in the GPS vertical and horizontal correlate to increasingly well-understood short-term mass variability,such as monsoonal flooding in Bangladesh,sub-daily changes in tidal loading at continent scales,day-to-day surface water and ice storage in the western U.S.,variations in the rate of GIA in Greenland across a variety of scales,and improved understanding of the inter-annual variation in sea level rise due to changes in terrestrial water storage.展开更多
Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination...Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination between Geodesy and Geodynamics,deepen the application of Geodesy in the field of Geoscience and quicken worldwide fellows’understanding on scientific research activity in China.It mainly publishes newest research achievements in the field of Geodesy,Geodynamics,Science of Disaster and so on.展开更多
Aims:The Journal of Geodesy and Geoinformation Science is an official publication of the Chinese Society for Geodesy,Photogrammetry and Cartography. The Journal aims to facilitate and strengthen academic exchange on g...Aims:The Journal of Geodesy and Geoinformation Science is an official publication of the Chinese Society for Geodesy,Photogrammetry and Cartography. The Journal aims to facilitate and strengthen academic exchange on geodesy and geoinformation research between China and other countries. Furthermore,it makes efforts to offer a forum for discussion between researchers in China and abroad.展开更多
On January 8,2022,a 6.9 magnitude earthquake occurred in Menyuan County,Qinghai Province,with the epicenter located at the intersection of the Tuolaishan Fault and the Lenglongling Fault,which are part of the Qilian—...On January 8,2022,a 6.9 magnitude earthquake occurred in Menyuan County,Qinghai Province,with the epicenter located at the intersection of the Tuolaishan Fault and the Lenglongling Fault,which are part of the Qilian—Haiyuan fault zone.This study investigated the sliding characteristics and seismic mechanism of the earthquake to understand the activity and seismic risk of the fault on the northeastern margin of the Qinghai—Tibet Plateau.This paper analyzed Sentinel-1 synthetic aperture radar images to obtain the coseismic deformation field of the earthquake,which was then used to invert the slip distribution of the seismogenic fault and the coseismic Coulomb stress on the surrounding faults caused by the earthquake.It was found that the earthquake was primarily characterized by sinistral strike-slip movement.Along the satellite line of sight,the south wall of the fault had a maximum deformation of 0.62 m,and the north wall had a maximum deformation of 0.48 m.The coseismic slip distribution results indicated that the maximum slip of the earthquake was 4.51 m,and the moment magnitude was MW6.7.The Coulomb stress analysis showed that the 2016 Menyuan earthquake promoted the occurrence of the 2022Menyuan earthquake.展开更多
This paper presents the past,present and future status of the Russian VLBI network "Quasar".This network has been developed for at least 20 years by the Institute of Applied Astronomy of the Russian Academy ...This paper presents the past,present and future status of the Russian VLBI network "Quasar".This network has been developed for at least 20 years by the Institute of Applied Astronomy of the Russian Academy of Sciences(IAA RAS). The equipment installed currently at each "Quasar" station and the facilities for processing observational data are described briefly. The latest results are presented, including the Earth orientation parameters(EOP) determined from the "Quasar" VLBI data and comparison with those from other processing centers. Our future plans to extend the "Quasar" VLB I network to the east and to the west will be carried out by establishing the Ussurijsk station in the Far East and the RussianCuban station in the west. They are considered in the context of the Russian section activity in the GGOS project. The expected improvement of the EOP determination accuracy can be obtained within the future configuration of the "Quasar" network,which is proved by simulation.展开更多
Territorial water is a significant part of national sovereignty of China,thus the infrastructures of national space datum and location services should cover the sea areas except for the land areas.China has establishe...Territorial water is a significant part of national sovereignty of China,thus the infrastructures of national space datum and location services should cover the sea areas except for the land areas.China has established relatively complete geodetic coordinate frame in land areas over the past decades,including the lastest developed China Geodetic Coordinate System 2000(CGCS 2000)with its reference frame and the national gravity datum 2000.However,the currently used geodetic infrastructures have not well covered the sea areas of China.The marine geodetic datum and marine navigation technologies need to be further developed and extended to satisfy the national demands of marine environment and resources detection,scientific investigation as well as marine economy development in new era of China.This paper mainly reviews the development and the progress of Chinese marine geodetic datum and marine navigation,analyses related key technologies in establishing our national marine geodetic datum.Some current trends and future directions for independently developing our national marine geodetic datum and marine navigation technologies are discussed.展开更多
The analysis of geodetic observations carried out by 478 continuous GPS stations in the Italian region since 2001 has allowed a fairly good definition of the ongoing horizontal velocity field with respect to Eurasia. ...The analysis of geodetic observations carried out by 478 continuous GPS stations in the Italian region since 2001 has allowed a fairly good definition of the ongoing horizontal velocity field with respect to Eurasia. It is argued that such evidence can provide important insights into the geodynamic context in the central Mediterranean area. Numerous velocity vectors in the Apulia zone coherently indicate that the southern Adriatic domain is moving roughly NE ward. Since no significant decoupling zone between this domain and Nubia has so far been recognized, one could expect that the kinematics of these two plates is compatible. However, this condition is not fulfilled if the Nubia-Eurasia relative motion is taken from the global kinematic models, either deduced by long-term evidence?[1]?or short-term geodetic data?[2]?[3]. This problem is considerably reduced if the alternative Nubia-Eurasia rotation pole suggested by?[4]?is taken into account. This choice is also suggested by other major long-term evidence in the Mediterranean region. The numerous geodetic vectors available in two Adriatic sectors, the Apulia zone and the Venetian plain, would imply an Adria-Eurasia rotation pole incompatible with all Nubia-Eurasia Eulerian poles so far proposed. Since a significant relative motion between these plates is not compatible with the absence of a tectonic decoupling zone, we suppose that the short-term kinematics of Adria might be influenced by a transient non-rigid behaviour of that plate. This hypothesis is compatible with the expected effects (post seismic relaxation) of the major decoupling earthquakes that have occurred along Periadriatic zones in the past tens of years. The compatibility of the GPS kinematic pattern in the Apennine belt, Calabria Arc and Sicily with the implications of the geodynamic/tectonic interpretations so far proposed for the central Mediterranean area is then discussed.展开更多
The knowledge of the geodetic reference datum of maps or data is required for their use in a GIS. Many older maps are lacking this information, making their use cumbersome. The availability of an aerial coverage at hi...The knowledge of the geodetic reference datum of maps or data is required for their use in a GIS. Many older maps are lacking this information, making their use cumbersome. The availability of an aerial coverage at high resolution of Burundi and digital elevation model, based on a novel geodetic network, all calculated on the WGS84 datum, allows to calculate the datum applicable to older maps, for instance the regular 1/50k map of the country. The method, based on the difference in geocentric coordinates between points common to the two systems, yields: Δx = -156.71 ± 10.2 m, .Δy = -3.26 ± 13.2 m, .Δz = -290.77 ± 21.06 m, well in keeping with older values proposed by the NGA.展开更多
After the M7.7 earthquake in 2001,the Kachchh rift basin became the focus of various geological and geophysical researches on the western Indian plate.As an essential technology,the Global Navigation Satellite System(...After the M7.7 earthquake in 2001,the Kachchh rift basin became the focus of various geological and geophysical researches on the western Indian plate.As an essential technology,the Global Navigation Satellite System(GNSS)has been utilized to study the deformation pattern in the central mainland Kachchh.We select the east-west striking Katrol Hill Fault(KHF)as the study area and analyze the crustal deformation pattern using the datasets from 2014 to 2019.The geodetic results along the KHF reveal a mean deformation of about 2.1 mm per year,which is higher in the eastern part and lower in the central and western parts.The investigation of deformation and derived strain reveals the segmented behavior of KHF,while the dominance of compressive strain(maximum 22 nanostrain/yr)in the eastern segment makes it the most active segment of the KHF.A higher deformation rate along the eastern KHF can be considered significant in terms of seismic hazard for this part of the Indian plate.展开更多
Based on the coordinates, velocities and their error estimations of 595 GPS, SLR and VLBI stations issued by IERS in March 2001, the current asymmetrical deformation of the Earth is studied. The results show that the ...Based on the coordinates, velocities and their error estimations of 595 GPS, SLR and VLBI stations issued by IERS in March 2001, the current asymmetrical deformation of the Earth is studied. The results show that the northern hemisphere of the Earth is undergoing compressive deformation, and the southern hemisphere is undergoing extensional deformation with the equator as the boundary. If the longitude line of 90°E and 90°W is taken as the boundary, the Pacific hemisphere (with 180° as its central longitude) is undergoing compressive deformation, and the Atlantic hemisphere (with 0° as its central longitude) is undergoing extensional deformation. The deformation patterns indicate again that the Earth is undergoing some dual-asymmetrical deformation. Moreover, taking 6 366.740 km as the standard mean curvature radius of the Earth, the velocity of volume change calculated from the data of space geodesy is 6.65x10-(11)m3/a.展开更多
Based on modern geometrical field theory, a rational interpretation of modern geodesic surface concept was formulated. The general equations for geodesic surface were given. The height concept and arc length concept w...Based on modern geometrical field theory, a rational interpretation of modern geodesic surface concept was formulated. The general equations for geodesic surface were given. The height concept and arc length concept were formulated strictly. Their intrinsic benefits and shortages of parameter-center reference and mass-center reference systems were studied in details. The research results show that the geodesic concept depends on the available technology. The technology-dependence feature of geodesy concept was expressed by related mathematic formulations. For the satellite-based observation system, the rationality of China-2000 Geoid Reference System was explained. Discussions about how to establish regional precision reference system were made based on general equations of arc length and space distance equations. A new correction item should be taken into consideration for arc length gauge calculation.展开更多
基金National Natural Science Foundation of China(No.41931076)Laoshan Laboratory(No.LSKJ202205105)+1 种基金National Key R&D Program of China(No.2020YFB0505802)State Key Laboratory of Geo-information Engineering(No.SKLGIE2020-M-1-1)。
文摘The ocean accounts for approximately 71%of the total area of the Earth.Whether it is studying the shape of the Earth itself through geodesy or the future development of earth system science,strengthening the construction of ocean geodesy disciplines and innovating ocean geodetic observation technologies have evident theoretical and practical significance.In recent years,the discipline of ocean geodesy in China has been continuously developing and growing,and notable breakthroughs have been made in ocean satellite geodesy and seafloor geodetic observation technology.Research on ocean geodetic observation models and algorithms has also made great progress.
基金National Natural Science Foundation of China(41931076)National Natural Science Foundation of China(41721003)。
文摘The geodesy discipline has been evolving and constantly intersecting and merging with other disciplines in the last 50 years,due to the continuous progress of geodetic observation techniques and expansion of application fields.This paper first introduces the development and roles of geodesy and its formation.Secondly,the development status of geodesy discipline is analyzed from the progress of observation techniques and cross-discipline formation is analyzed from the expansion of application fields.Furthermore,the development trend of geodesy is stated from the perspective of national requirements and scientific developments.Finally,the sub-disciplines for geodesy are suggested at the present stage,based on the requirements of the National Natural Science Foundation of China and development status of geodesy itself,which can provide references for topic selection and fund application of geodetic scientific research.
基金supported by the NSFC projects(Grant Nos:41431069,41574002and 41721003).
文摘To overcome the high cost of learning,non-visual operation,and cumbersome steps of fine-tuning map elements in Generic Mapping Tools(GMT)and other geoscience mapping softwares,we present the Tectonic Geodesy Application(TGA),a user-friendly 64-bit tectonic geodesy mapping software based on the secondary development interface of the open source geographic information system QGIS.In this paper,we detailly introduce the architecture and function modules of our software,and highlight the functions of rendering and map decoration through four cases:the geologic map of Papua New Guinea,the seismicity in China and surrounding regions,the seismicity and crustal deformation of the Tibetan Plateau and the coseismic deformation of the 2017 Jiuzhaigou earthquake in China.Compared with GMT,the tectonic geodesy mapping software we developed has the advantages of simple operation,low learning cost and user-friendly interface.
文摘Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world. Its aim is to promote a combination between Geodesy and Geodynamics, deepen the application of Geodesy in the field of Geoscience and quicken worldwide fellows’ understanding on scientific research activity in China. It mainly
文摘"Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opportunity for participants from Canada and from around the world to come together and share their science and culture.2019 marks the 100th anniversary of IUGG;we will look back on the accomplishments of the previous century of Earth and space science research,and forward to the next century of scientific advancement.Join us for a host of scientific activities,including special public lectures,keynote Union lectures and a wide variety of themed sessions.
文摘UNAVCO supports geoscience research at 113 US academic Member institutions,and another 104 Associate Member institutions include international universities,laboratories,observatories,academies of science,and a museum.This diverse membership shares UNAVCO’s purpose at home and abroad,giving UNAVCO global reach in advancing geodesy.Since the mid-1980s,modern geodesy has evolved into a cutting-edge,multi-faceted toolbox with remarkably diverse research and real-world applications,including studies and observation or forecasting of solid-Earth hazards,the dynamics of the atmosphere,climate,near-Earth space environment,and of key environmental parameters such as water storage,soil moisture,and seaand lake-level changes.UNAVCO operates facilities on behalf of the U.S.National Science Foundation to support investigators who use geodetic tools across all of these Earth and atmospheric domains.UNAVCO has built a number of large dense regional networks of GPS stations,including the Earth Scope Plate Boundary Observatory in North America,the COCONetCaribbean network,TLALOCNet in Mexico,GNET in Greenland,and ANET in Antarctica.Going forward,UNAVCO plans to federate the Plate Boundary Observatory(USA),TLALOCNet(Mexico),and COCONet(Caribbean)GPS networks as the Network of the Americas,with upgrades to state-of-the-art,multi-sensor,multi-GNSS observations.While UNAVCO community scientists actively engage in using space and terrestrial geodetic techniques to study geodynamics at all scales,this proliferation of continuous networks is the basis for a suite of recent contributions that focus on improved daily positioning to sense Earth’s elastic response and other perturbations to loading by atmospheric and surface water,oceans,and ice.Day-to-day and sub-daily variations in the GPS vertical and horizontal correlate to increasingly well-understood short-term mass variability,such as monsoonal flooding in Bangladesh,sub-daily changes in tidal loading at continent scales,day-to-day surface water and ice storage in the western U.S.,variations in the rate of GIA in Greenland across a variety of scales,and improved understanding of the inter-annual variation in sea level rise due to changes in terrestrial water storage.
文摘Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination between Geodesy and Geodynamics,deepen the application of Geodesy in the field of Geoscience and quicken worldwide fellows’understanding on scientific research activity in China.It mainly publishes newest research achievements in the field of Geodesy,Geodynamics,Science of Disaster and so on.
文摘Aims:The Journal of Geodesy and Geoinformation Science is an official publication of the Chinese Society for Geodesy,Photogrammetry and Cartography. The Journal aims to facilitate and strengthen academic exchange on geodesy and geoinformation research between China and other countries. Furthermore,it makes efforts to offer a forum for discussion between researchers in China and abroad.
基金supported by the Natural Science Foundation of China(Grant Nos.42104061)Shaanxi Province natural science basic research program(Grant Nos.2023-JC-QN-0296)Science for Earthquake Resilience(Grant Nos.XH23059YA)。
文摘On January 8,2022,a 6.9 magnitude earthquake occurred in Menyuan County,Qinghai Province,with the epicenter located at the intersection of the Tuolaishan Fault and the Lenglongling Fault,which are part of the Qilian—Haiyuan fault zone.This study investigated the sliding characteristics and seismic mechanism of the earthquake to understand the activity and seismic risk of the fault on the northeastern margin of the Qinghai—Tibet Plateau.This paper analyzed Sentinel-1 synthetic aperture radar images to obtain the coseismic deformation field of the earthquake,which was then used to invert the slip distribution of the seismogenic fault and the coseismic Coulomb stress on the surrounding faults caused by the earthquake.It was found that the earthquake was primarily characterized by sinistral strike-slip movement.Along the satellite line of sight,the south wall of the fault had a maximum deformation of 0.62 m,and the north wall had a maximum deformation of 0.48 m.The coseismic slip distribution results indicated that the maximum slip of the earthquake was 4.51 m,and the moment magnitude was MW6.7.The Coulomb stress analysis showed that the 2016 Menyuan earthquake promoted the occurrence of the 2022Menyuan earthquake.
文摘This paper presents the past,present and future status of the Russian VLBI network "Quasar".This network has been developed for at least 20 years by the Institute of Applied Astronomy of the Russian Academy of Sciences(IAA RAS). The equipment installed currently at each "Quasar" station and the facilities for processing observational data are described briefly. The latest results are presented, including the Earth orientation parameters(EOP) determined from the "Quasar" VLBI data and comparison with those from other processing centers. Our future plans to extend the "Quasar" VLB I network to the east and to the west will be carried out by establishing the Ussurijsk station in the Far East and the RussianCuban station in the west. They are considered in the context of the Russian section activity in the GGOS project. The expected improvement of the EOP determination accuracy can be obtained within the future configuration of the "Quasar" network,which is proved by simulation.
文摘Territorial water is a significant part of national sovereignty of China,thus the infrastructures of national space datum and location services should cover the sea areas except for the land areas.China has established relatively complete geodetic coordinate frame in land areas over the past decades,including the lastest developed China Geodetic Coordinate System 2000(CGCS 2000)with its reference frame and the national gravity datum 2000.However,the currently used geodetic infrastructures have not well covered the sea areas of China.The marine geodetic datum and marine navigation technologies need to be further developed and extended to satisfy the national demands of marine environment and resources detection,scientific investigation as well as marine economy development in new era of China.This paper mainly reviews the development and the progress of Chinese marine geodetic datum and marine navigation,analyses related key technologies in establishing our national marine geodetic datum.Some current trends and future directions for independently developing our national marine geodetic datum and marine navigation technologies are discussed.
文摘The analysis of geodetic observations carried out by 478 continuous GPS stations in the Italian region since 2001 has allowed a fairly good definition of the ongoing horizontal velocity field with respect to Eurasia. It is argued that such evidence can provide important insights into the geodynamic context in the central Mediterranean area. Numerous velocity vectors in the Apulia zone coherently indicate that the southern Adriatic domain is moving roughly NE ward. Since no significant decoupling zone between this domain and Nubia has so far been recognized, one could expect that the kinematics of these two plates is compatible. However, this condition is not fulfilled if the Nubia-Eurasia relative motion is taken from the global kinematic models, either deduced by long-term evidence?[1]?or short-term geodetic data?[2]?[3]. This problem is considerably reduced if the alternative Nubia-Eurasia rotation pole suggested by?[4]?is taken into account. This choice is also suggested by other major long-term evidence in the Mediterranean region. The numerous geodetic vectors available in two Adriatic sectors, the Apulia zone and the Venetian plain, would imply an Adria-Eurasia rotation pole incompatible with all Nubia-Eurasia Eulerian poles so far proposed. Since a significant relative motion between these plates is not compatible with the absence of a tectonic decoupling zone, we suppose that the short-term kinematics of Adria might be influenced by a transient non-rigid behaviour of that plate. This hypothesis is compatible with the expected effects (post seismic relaxation) of the major decoupling earthquakes that have occurred along Periadriatic zones in the past tens of years. The compatibility of the GPS kinematic pattern in the Apennine belt, Calabria Arc and Sicily with the implications of the geodynamic/tectonic interpretations so far proposed for the central Mediterranean area is then discussed.
文摘The knowledge of the geodetic reference datum of maps or data is required for their use in a GIS. Many older maps are lacking this information, making their use cumbersome. The availability of an aerial coverage at high resolution of Burundi and digital elevation model, based on a novel geodetic network, all calculated on the WGS84 datum, allows to calculate the datum applicable to older maps, for instance the regular 1/50k map of the country. The method, based on the difference in geocentric coordinates between points common to the two systems, yields: Δx = -156.71 ± 10.2 m, .Δy = -3.26 ± 13.2 m, .Δz = -290.77 ± 21.06 m, well in keeping with older values proposed by the NGA.
基金Director-General,ISR&DST-Govt.of Gujarat,for the necessary support to carry out the research work。
文摘After the M7.7 earthquake in 2001,the Kachchh rift basin became the focus of various geological and geophysical researches on the western Indian plate.As an essential technology,the Global Navigation Satellite System(GNSS)has been utilized to study the deformation pattern in the central mainland Kachchh.We select the east-west striking Katrol Hill Fault(KHF)as the study area and analyze the crustal deformation pattern using the datasets from 2014 to 2019.The geodetic results along the KHF reveal a mean deformation of about 2.1 mm per year,which is higher in the eastern part and lower in the central and western parts.The investigation of deformation and derived strain reveals the segmented behavior of KHF,while the dominance of compressive strain(maximum 22 nanostrain/yr)in the eastern segment makes it the most active segment of the KHF.A higher deformation rate along the eastern KHF can be considered significant in terms of seismic hazard for this part of the Indian plate.
基金State Natural Science Foundation of China (49834020).
文摘Based on the coordinates, velocities and their error estimations of 595 GPS, SLR and VLBI stations issued by IERS in March 2001, the current asymmetrical deformation of the Earth is studied. The results show that the northern hemisphere of the Earth is undergoing compressive deformation, and the southern hemisphere is undergoing extensional deformation with the equator as the boundary. If the longitude line of 90°E and 90°W is taken as the boundary, the Pacific hemisphere (with 180° as its central longitude) is undergoing compressive deformation, and the Atlantic hemisphere (with 0° as its central longitude) is undergoing extensional deformation. The deformation patterns indicate again that the Earth is undergoing some dual-asymmetrical deformation. Moreover, taking 6 366.740 km as the standard mean curvature radius of the Earth, the velocity of volume change calculated from the data of space geodesy is 6.65x10-(11)m3/a.
文摘Based on modern geometrical field theory, a rational interpretation of modern geodesic surface concept was formulated. The general equations for geodesic surface were given. The height concept and arc length concept were formulated strictly. Their intrinsic benefits and shortages of parameter-center reference and mass-center reference systems were studied in details. The research results show that the geodesic concept depends on the available technology. The technology-dependence feature of geodesy concept was expressed by related mathematic formulations. For the satellite-based observation system, the rationality of China-2000 Geoid Reference System was explained. Discussions about how to establish regional precision reference system were made based on general equations of arc length and space distance equations. A new correction item should be taken into consideration for arc length gauge calculation.
