A long-term （9 years） gravity change in Chinese mainland is obtained on the basis of observation of the ground-based national gravity network. The result shows several features that may be related to sore, large-sca...A long-term （9 years） gravity change in Chinese mainland is obtained on the basis of observation of the ground-based national gravity network. The result shows several features that may be related to sore, large-scale groundwater pumping in North China, glacier-water flow and storage in Tianshan region, and pre seismic gravity changes of the 2008 MsS. 0 Wenchuan earthquake, which are spatially similar to co-seismi, changes but reversed in sign. These features are also shown in the result of the satellite-based GRACE obser vation, after a height effect is corrected with GPS data.展开更多
To better understand the heterogeneity of deep-crust and mantle interfaces in the region of the Three Gorges, China, we used the Parker-Oldenburg iterative inversion method to invert existing Bouguer gravity data from...To better understand the heterogeneity of deep-crust and mantle interfaces in the region of the Three Gorges, China, we used the Parker-Oldenburg iterative inversion method to invert existing Bouguer gravity data from the Three Gorges area （ 1 ： 500000） , a new gravity map of the Three Gorges Dam （ 1 ： 200000） , and the results of deep seismic soundings. The inversion results show a Moho depth of 42 km be- tween Badong and Zigui and the depth of the B2 lower-crustal interface beneath the Jianghan Plain and sur- rounding areas at 21 -25 km. The morphology of crustal interfaces and the surface geology present an over- pass structure. The mid-crust beneath the Three Gorges Dam is approximately 9 km thick, which is the thin- nest in the Three Gorges area and may be related to the shallow low-density body near the Huangling anti- cline. The upper crust is seismogenic, and there is a close relationship between seismicity and the deep- crust and mantle interfaces. For example, the MS. 1 Zigui earthquake occurred where the gradients of the Moho and the B2 interface are the steepest, showing that deep structure has a very important effect on re- gional seismicity.展开更多
By using absolute and relative-gravity data recorded by the gravity network in North China, we obtained some large-scale and high-spatial-resolution images of gravity variation in this area for the first time. By anal...By using absolute and relative-gravity data recorded by the gravity network in North China, we obtained some large-scale and high-spatial-resolution images of gravity variation in this area for the first time. By analyzing these images, we found that the gravity in Liaodong peninsula area showed an obvious increase of 80 × 10^-8ms^-2 during about one- and-half year before the 2011 Japan Mwg. 0 earthquake, and a rapid decrease after the earthquake. This gravity variation is similar to that observed previously for the 1976 Tangshan 1147.8 earthquake.展开更多
This paper introduces the comparison of absolute gravity measurements in China during 2006-2008,and analyzing the survey and comparing the results,it shows that there is no obvious system error between the gravimeter ...This paper introduces the comparison of absolute gravity measurements in China during 2006-2008,and analyzing the survey and comparing the results,it shows that there is no obvious system error between the gravimeter of FG5/214 and FG5/232,the surveying accuracy is very high and repetition is good,and their inner surveying accuracy is about 2-3 microGal.展开更多
基金supported by the National Natural Science Foundation of China (41004030)
文摘A long-term （9 years） gravity change in Chinese mainland is obtained on the basis of observation of the ground-based national gravity network. The result shows several features that may be related to sore, large-scale groundwater pumping in North China, glacier-water flow and storage in Tianshan region, and pre seismic gravity changes of the 2008 MsS. 0 Wenchuan earthquake, which are spatially similar to co-seismi, changes but reversed in sign. These features are also shown in the result of the satellite-based GRACE obser vation, after a height effect is corrected with GPS data.
基金supported by grant 201008001 from China Earthquake Ad-ministration201156085 from Institute of Seismology,China Earthquake Administration
文摘To better understand the heterogeneity of deep-crust and mantle interfaces in the region of the Three Gorges, China, we used the Parker-Oldenburg iterative inversion method to invert existing Bouguer gravity data from the Three Gorges area （ 1 ： 500000） , a new gravity map of the Three Gorges Dam （ 1 ： 200000） , and the results of deep seismic soundings. The inversion results show a Moho depth of 42 km be- tween Badong and Zigui and the depth of the B2 lower-crustal interface beneath the Jianghan Plain and sur- rounding areas at 21 -25 km. The morphology of crustal interfaces and the surface geology present an over- pass structure. The mid-crust beneath the Three Gorges Dam is approximately 9 km thick, which is the thin- nest in the Three Gorges area and may be related to the shallow low-density body near the Huangling anti- cline. The upper crust is seismogenic, and there is a close relationship between seismicity and the deep- crust and mantle interfaces. For example, the MS. 1 Zigui earthquake occurred where the gradients of the Moho and the B2 interface are the steepest, showing that deep structure has a very important effect on re- gional seismicity.
基金supported by the Special Social Commonweal Research of the State( 2005DIB3J120) the Director Foundation of the Institute of Seismology,China Earthquake Administration ( IS200956045) Special Foundation for Earthquake Monitoring and Tracing in North China
文摘By using absolute and relative-gravity data recorded by the gravity network in North China, we obtained some large-scale and high-spatial-resolution images of gravity variation in this area for the first time. By analyzing these images, we found that the gravity in Liaodong peninsula area showed an obvious increase of 80 × 10^-8ms^-2 during about one- and-half year before the 2011 Japan Mwg. 0 earthquake, and a rapid decrease after the earthquake. This gravity variation is similar to that observed previously for the 1976 Tangshan 1147.8 earthquake.
基金Supported by the Fund of Institute of Seismology,CEA (No.IS200736026)
文摘This paper introduces the comparison of absolute gravity measurements in China during 2006-2008,and analyzing the survey and comparing the results,it shows that there is no obvious system error between the gravimeter of FG5/214 and FG5/232,the surveying accuracy is very high and repetition is good,and their inner surveying accuracy is about 2-3 microGal.
