Due to the complex nature of multi-source geological data, it is difficult to rebuild every geological structure through a single 3D modeling method. The multi-source data interpretation method put forward in this ana...Due to the complex nature of multi-source geological data, it is difficult to rebuild every geological structure through a single 3D modeling method. The multi-source data interpretation method put forward in this analysis is based on a database-driven pattern and focuses on the discrete and irregular features of geological data. The geological data from a variety of sources covering a range of accuracy, resolution, quantity and quality are classified and integrated according to their reliability and consistency for 3D modeling. The new interpolation-approximation fitting construction algorithm of geological surfaces with the non-uniform rational B-spline(NURBS) technique is then presented. The NURBS technique can retain the balance among the requirements for accuracy, surface continuity and data storage of geological structures. Finally, four alternative 3D modeling approaches are demonstrated with reference to some examples, which are selected according to the data quantity and accuracy specification. The proposed approaches offer flexible modeling patterns for different practical engineering demands.展开更多
Using the teleseismic waveform data recorded by the seismic station Bachu (hereafter referred to as station BCH ) in the Tarim Basin and the seismic station Taxkorgan (hereafter referred to as station TAG ) in the...Using the teleseismic waveform data recorded by the seismic station Bachu (hereafter referred to as station BCH ) in the Tarim Basin and the seismic station Taxkorgan (hereafter referred to as station TAG ) in the west Kunlun Mountains for years, we applied the receiver function H - K stacking method to study the crustal structure beneath stations BCH and TAG. The results showed that there are obvious differences in the crustal thickness beneath stations BCH and TAG, and the regional crustal thickness and terrain have a very good corresponding relationship. There are high crustal average Vp/Vs values beneath the two stations. The crustal thickness is 44km, and the crustal average wave velocity ratio is 1. 849 beneath station BCH. There is a sharp discontinuity in the middle of the crust beneath station BCH at a depth of 21km. There is a low average P wave velocity and low Vp/Vs from the surface to the discontinuity beneath station BCH. The depth of the discontinuity is consistent with the lower interface of the focal depth from accurate location in the Jiashi earthquake source area adjacent to station BCH; and may be the crustal brittle-ductile conversion boundary. The crustal thickness is 69km, and the crustal average wave velocity ratio is 1. 847 beneath station TAG, a thicker crust and high Vp/Vs may indicate that materials in the lower crustal are prone to plastic flow, which is responsible for the thickening of the crust.展开更多
The aim of this study was to determine the phytoplankton community structures of reservoirs of different trophic status, located in a cold region. Physical and chemical variables and the phytoplankton communities were...The aim of this study was to determine the phytoplankton community structures of reservoirs of different trophic status, located in a cold region. Physical and chemical variables and the phytoplankton communities were investigated in two reservoirs (Xiquanyan Reservoir and Taoshan Reservoir) in Northeast China in 2009. The two reservoirs showed strong seasonal fluctuations in their physical and chemical composition. Results of the trophic status index indicated that Xiaquanyan Reservoir was mesotrophic, whilst Taoshan Reservoir was eutrophic. Diatoms were the dominant phytoplankton group in Xiquanyan Reservoir throughout all seasons of the study, while in Taoshan Reservoir, diatoms dominated in spring, and cyanobacteria dominated in summer and autumn. This difference was resulted from differences in local environmental factors, including nutrients and hydrology. This study suggests that in mesotrophic reservoirs, nutrients played a key role in controlling seasonal phytoplankton successions, whereas in eutrophic reservoirs water temperature was the key factor in a cold region. Notably, the dominant species in summer in the Taoshan Reservoir was Microcystis, which may produce toxins depending on the ambient conditions, and presenting a risk of local toxin contamination.展开更多
The Shanxi reservoir earthquakes are significant seismic events in southern Zhejiang Province in recent years, an area with fewer and weaker earthquakes. The seismicity showed an intermittent characteristic and group ...The Shanxi reservoir earthquakes are significant seismic events in southern Zhejiang Province in recent years, an area with fewer and weaker earthquakes. The seismicity showed an intermittent characteristic and group distribution. The epicenters located by the seismic network did not show a predominant direction and the seismogenic structure is not clear. In the study, the nonlinear imaginary wave travel time equation was linearized and solved, and the source position, initial imaginary velocity and travel time residuals were obtained. Then by doubling the standard deviation as time residuals, the maximum error generated from longitude, latitude, depth and imaginary velocity was calculated. The genetic population was structured using the maximum error and the end result of earthquake location was obtained by genetic algorithm. The result of relocation of the Shanxi reservoir earthquakes with this method shows that earthquakes are largely concentrated on a near-vertical, northwest oriented fault plane, and the included angles between the normal of the plane and the due north, due east and vertical directions are 46~, 44~, and 87~, respectively. The result is in agreement with that of comprehensive fault plane solutions of small earthquakes. The average depth of the earthquakes was 4.7km, the maximum depth 9.5kin, and the minimum depth 1.7km. The epicenters showed a northwestward narrow banded distribution, and the focal depth increased along the northwest direction. There was a discontinuous seismic gap of about 3.5km long at the northwest end of the strip. The characteristics of source parameters obtained by using the Borun model were not significantly different from that of tectonic earthquakes. Seismic stress drop was about 0.33MPa, and the average stress drop was 0.88MPa. According to the stress drop' spatial distribution, the seismic discontinuities segment at the northwest end of the strip is in a low stress drop zone.展开更多
Using the data of P-wave network and Zhejiang and travel time recorded at the Shanxi-reservoir seismological Fujian local networks, we implemented a simultaneous inversion of earthquake relocation and velocity struct...Using the data of P-wave network and Zhejiang and travel time recorded at the Shanxi-reservoir seismological Fujian local networks, we implemented a simultaneous inversion of earthquake relocation and velocity structure and determined the new locations of earthquakes in the Shanxi-reservoir. The results show that: (1) the overall epicenter distribution is NW directed, and the Shanxi reservoir induced seismicity has a close relationship to the Shuangxi-Jiaoxiyang fault; (2) the focal depth of the Shanxi reservoir induced seismicity is 5.4km in average, less than the average focal depth in the South China earthquake zone; (3) the focal depth is shallower on the reservoir shore and deeper in the reservoir inundation area. At the beginning of the reservoir induced seismicity, the focal depth increased gradually. This may be due to the gradual penetration of water into a larger depth that induced deeper earthquakes; and (4) there is a low P-wave velocity anomaly in the study area, located at the intersection of multiple faults in the reservoir inundation area. The Shanxi reservoir induced seismicity mostly occurred in this lowvelocity anomaly zone. This may be related to water penetration.展开更多
The present condition of Southern Kazakhstan natural reservoirs is represented in the article. The research was held in summer time of 2010. Quantitative and qualitative features and dominating types of zooplankton of...The present condition of Southern Kazakhstan natural reservoirs is represented in the article. The research was held in summer time of 2010. Quantitative and qualitative features and dominating types of zooplankton of the individual reservoirs are shown. It is detected that the waters of the South Kazakhstan oblast (region) are inhabited by 70 types of zooplankton organisms of different taxonomic groups, whose association to certain reservoir depends on the hydrochemical indicators of the aquatic environment.展开更多
基金Supported by the National Natural Science Foundation of China(No.51379006 and No.51009106)the Program for New Century Excellent Talents in University of Ministry of Education of China(No.NCET-12-0404)the National Basic Research Program of China("973"Program,No.2013CB035903)
文摘Due to the complex nature of multi-source geological data, it is difficult to rebuild every geological structure through a single 3D modeling method. The multi-source data interpretation method put forward in this analysis is based on a database-driven pattern and focuses on the discrete and irregular features of geological data. The geological data from a variety of sources covering a range of accuracy, resolution, quantity and quality are classified and integrated according to their reliability and consistency for 3D modeling. The new interpolation-approximation fitting construction algorithm of geological surfaces with the non-uniform rational B-spline(NURBS) technique is then presented. The NURBS technique can retain the balance among the requirements for accuracy, surface continuity and data storage of geological structures. Finally, four alternative 3D modeling approaches are demonstrated with reference to some examples, which are selected according to the data quantity and accuracy specification. The proposed approaches offer flexible modeling patterns for different practical engineering demands.
基金sponsored by the Seismic Networks Young Junior Training Project(20130216)the Earthquake Science and Technology Spark Program from China Earthquake Administration(XH15046)
文摘Using the teleseismic waveform data recorded by the seismic station Bachu (hereafter referred to as station BCH ) in the Tarim Basin and the seismic station Taxkorgan (hereafter referred to as station TAG ) in the west Kunlun Mountains for years, we applied the receiver function H - K stacking method to study the crustal structure beneath stations BCH and TAG. The results showed that there are obvious differences in the crustal thickness beneath stations BCH and TAG, and the regional crustal thickness and terrain have a very good corresponding relationship. There are high crustal average Vp/Vs values beneath the two stations. The crustal thickness is 44km, and the crustal average wave velocity ratio is 1. 849 beneath station BCH. There is a sharp discontinuity in the middle of the crust beneath station BCH at a depth of 21km. There is a low average P wave velocity and low Vp/Vs from the surface to the discontinuity beneath station BCH. The depth of the discontinuity is consistent with the lower interface of the focal depth from accurate location in the Jiashi earthquake source area adjacent to station BCH; and may be the crustal brittle-ductile conversion boundary. The crustal thickness is 69km, and the crustal average wave velocity ratio is 1. 847 beneath station TAG, a thicker crust and high Vp/Vs may indicate that materials in the lower crustal are prone to plastic flow, which is responsible for the thickening of the crust.
基金Supported by the Fundamental Research Funds for the Central Universities(No.DL11BA20)the GRAP09-Excellent Doctor Paper of Northeast Forestry Universitythe Science and Technology Project of Heilongjiang Province(No.GBQ9C103)
文摘The aim of this study was to determine the phytoplankton community structures of reservoirs of different trophic status, located in a cold region. Physical and chemical variables and the phytoplankton communities were investigated in two reservoirs (Xiquanyan Reservoir and Taoshan Reservoir) in Northeast China in 2009. The two reservoirs showed strong seasonal fluctuations in their physical and chemical composition. Results of the trophic status index indicated that Xiaquanyan Reservoir was mesotrophic, whilst Taoshan Reservoir was eutrophic. Diatoms were the dominant phytoplankton group in Xiquanyan Reservoir throughout all seasons of the study, while in Taoshan Reservoir, diatoms dominated in spring, and cyanobacteria dominated in summer and autumn. This difference was resulted from differences in local environmental factors, including nutrients and hydrology. This study suggests that in mesotrophic reservoirs, nutrients played a key role in controlling seasonal phytoplankton successions, whereas in eutrophic reservoirs water temperature was the key factor in a cold region. Notably, the dominant species in summer in the Taoshan Reservoir was Microcystis, which may produce toxins depending on the ambient conditions, and presenting a risk of local toxin contamination.
基金supported by the Science andTechnology Project of Zhejiang Province(2007C330060)the Special Research Fund for Seismic Industry of China Seismological Bureau(200808068)
文摘The Shanxi reservoir earthquakes are significant seismic events in southern Zhejiang Province in recent years, an area with fewer and weaker earthquakes. The seismicity showed an intermittent characteristic and group distribution. The epicenters located by the seismic network did not show a predominant direction and the seismogenic structure is not clear. In the study, the nonlinear imaginary wave travel time equation was linearized and solved, and the source position, initial imaginary velocity and travel time residuals were obtained. Then by doubling the standard deviation as time residuals, the maximum error generated from longitude, latitude, depth and imaginary velocity was calculated. The genetic population was structured using the maximum error and the end result of earthquake location was obtained by genetic algorithm. The result of relocation of the Shanxi reservoir earthquakes with this method shows that earthquakes are largely concentrated on a near-vertical, northwest oriented fault plane, and the included angles between the normal of the plane and the due north, due east and vertical directions are 46~, 44~, and 87~, respectively. The result is in agreement with that of comprehensive fault plane solutions of small earthquakes. The average depth of the earthquakes was 4.7km, the maximum depth 9.5kin, and the minimum depth 1.7km. The epicenters showed a northwestward narrow banded distribution, and the focal depth increased along the northwest direction. There was a discontinuous seismic gap of about 3.5km long at the northwest end of the strip. The characteristics of source parameters obtained by using the Borun model were not significantly different from that of tectonic earthquakes. Seismic stress drop was about 0.33MPa, and the average stress drop was 0.88MPa. According to the stress drop' spatial distribution, the seismic discontinuities segment at the northwest end of the strip is in a low stress drop zone.
基金supported by the National Key Technology R&D Program(2008BAC38B03-01-05)the Earthquake Scientific Research Project(200708020),China
文摘Using the data of P-wave network and Zhejiang and travel time recorded at the Shanxi-reservoir seismological Fujian local networks, we implemented a simultaneous inversion of earthquake relocation and velocity structure and determined the new locations of earthquakes in the Shanxi-reservoir. The results show that: (1) the overall epicenter distribution is NW directed, and the Shanxi reservoir induced seismicity has a close relationship to the Shuangxi-Jiaoxiyang fault; (2) the focal depth of the Shanxi reservoir induced seismicity is 5.4km in average, less than the average focal depth in the South China earthquake zone; (3) the focal depth is shallower on the reservoir shore and deeper in the reservoir inundation area. At the beginning of the reservoir induced seismicity, the focal depth increased gradually. This may be due to the gradual penetration of water into a larger depth that induced deeper earthquakes; and (4) there is a low P-wave velocity anomaly in the study area, located at the intersection of multiple faults in the reservoir inundation area. The Shanxi reservoir induced seismicity mostly occurred in this lowvelocity anomaly zone. This may be related to water penetration.
文摘The present condition of Southern Kazakhstan natural reservoirs is represented in the article. The research was held in summer time of 2010. Quantitative and qualitative features and dominating types of zooplankton of the individual reservoirs are shown. It is detected that the waters of the South Kazakhstan oblast (region) are inhabited by 70 types of zooplankton organisms of different taxonomic groups, whose association to certain reservoir depends on the hydrochemical indicators of the aquatic environment.