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971.
Dynamic simulation of interactions between major earthquakes on the Xianshuihe fault zone 总被引:3,自引:0,他引:3
The authors firstly evaluate the strain accumulation rate of the Xianshuihe fault zone based on earth- quake activity. We calculated the stress and seismic moment accumulation rate for each subsection of the Xianshuihe fault zone based on the distribution of geological slip rate and GPS survey results. According to the results, we get the recurrence intervals of characterized earthquakes on each sub- section respectively. A three-dimensional finite element model for western Sichuan is constructed to discuss the earthquakes triggering among major earthquakes (M>6.7) that occurred along the Xianshuihe fault zone since 1893. The calculated Coulomb failure stress changes (ΔCFS) show that 5 of the 6 earthquakes with Ms>6.7 were triggered by positive ΔCFS. The interactions between major earthquakes not only influence recurrence intervals of characterized earthquakes on each subsection, but also change recurrence behavior of major earthquakes along the whole fault zone. 相似文献
972.
With co-seismic surface rupture slip displacements provided by the field observation for the 2001 MS8.1 West Kunlun Mountain Pass earthquake, this paper estimates the rupture speed on the main faulting segment with a long straight fault trace on the surface based on a simple slip-weakening rupture model, in which the frictional overshoot or undershoot are involved in consideration of energy partition during the earthquake faulting. In contrast to the study of Bouchon and Vallée, in which the rupture propagation along the main fault could exceed the local shear-wave speed, perhaps reach the P-wave speed on a certain section of fault, our results show that, under a slip-weakening assumption combined with a frictional undershoot (partial stress drop model), average rupture speed should be equal to or less than the Rayleigh wave speed with a high seismic radiation efficiency, which is consistent with the result derived by waveform inversion and the result estimated from source stress field. Associated with the surface rupture mechanism, such as partial stress drop (frictional undershoot) associated with the apparent stress, an alternative rupture mechanism based on the slip-weakening model has also been discussed. 相似文献
973.
经验格林函数法与随机有限断层法在合成近场强地震动中的联合运用 总被引:1,自引:0,他引:1
本文采取将经验格林函数法与随机有限断层法相结合的方式,突出体现了各自方法的优点,通过经验格林函数法确定地震震源参数,用随机有限断层法计算参数、检验其合理性。利用1998年新疆阿图什M6.9级地震的肘L4.7级余震记录,合成了这次地震的最大余震Ms6.0级地震的加速度记录,并将合成的结果与实际记录在频域和时域做了对比,分析研究了地震动特征和这次最大余震的可能破裂特征。同时对经验格林函数法需进一步改进的方向进行了探讨。 相似文献
974.
几种海洋蓝藻生长条件的研究 总被引:4,自引:0,他引:4
对Synechococcus bacillaris,Oscillatoria lud,Schizothrix calcicola,Spirulina platensis等4各海洋蓝藻的生长条件的研究表明,除S.platensis外,其他3种蓝藻在“f/2”培养基中生长良好,外源生长因子对生长有不同程度的促进作用。S.bacillaris适应较高光强,其温度和pH最适范围较窄,S.calcicola 相似文献
975.
Using NCEP/NCAR reanalysis geopotential height (GHT) and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure
(SLP) and precipitation observations from more than 600 stations nationwide in June–August from 1951 to 2006, and focusing
on the East Asia-West Pacific region (10°–80°N, 70°–180°E), interannual variation of East Asian summer monsoon (EASM) and
its correlations with general circulation and precipitation patterns are studied by using statistical diagnostic methods such
as 9-point high pass filtering, empirical orthogonal function (EOF) analysis, composite analysis and other statistical diagnosis,
etc. It is concluded as follows: (1) EOF analysis of SLP in the East Asia-West Pacific region shows the existence of the zonal
dipole oscillation mode (APD) between the Mongolia depression and the West Pacific high, and APD index can be used as an intensity
index of EASM. (2) EOF analysis of GHT anomalies at 500 hPa in the East Asia-West Pacific region shows that the first EOF
mode is characterized with an obvious meridional East Asian pattern (EAP), and EAP index can also be used as an EASM intensity
index. (3) The composite analysis of high/low APD index years reveals the close correlation of APD index with EAP at 500 hPa
(or 850 hPa). The study shows an obvious opposite correlation exists between APD index and EAP index with a correlation coefficient
of −0.23, which passes the confidence test at 0.10 level. (4) Both APD and EAP indexes are closely correlated with precipitation
during flood-prone season in China and precipitation rate over the East Asia-West Pacific region. The significant correlation
area at 5% confidence level is mainly located from the southern area of the Yangtze River valley to the ocean around southern
Japan, and the former is a positive correlation and the latter is a negative one.
Foundation: Cooperative Project funded by the Ministry of Science and Technology of the People’s Republic of China, No.2007DFB20210;
National Natural Science Foundation of China, No.90502003; JICA China-Japan Technical Cooperative Project “China-Japanese
Cooperative Research Center on Meteorological Disasters”.
Author: Yu Shuqiu, Associate Professor, specialized in climate and climate change. 相似文献
976.
977.
978.
Peijian Shi Jie Liu Zhen Yang Agricultural College Jiangxi Agricultural University Nanchang China China Earthquake Networks Center Beijing China 《地震学报(英文版)》2009,(3):231-237
For exploring the aftershock occurrence process of the 2008 Wenchuan strong earthquake, the spatio-temporal point pattern analysis method is employed to study the sequences of aftershocks with magnitude M≥4.0, M≥4.5, and M≥5.0. It is found that these data exhibit the spatio-temporal clustering on a certain distance scale and on a certain time scale. In particular, the space-time interaction obviously strengthens when the distance is less than 60 km and the time is less than 260 h for the first two aftershoc... 相似文献
979.
“东半球空间环境地基综合监测子午链”(简称子午工程)是我国空间科学领域开工建设的第一个国家重大基础设施项目。子午工程利用沿东半球120°E子午线附近和北纬30°N附近的15个综合性观测台站,运用无线电、地磁、光学和探空火箭等多种探测手段,连续监测地球表面20—30km以上到几百公里的中高层大气、电离层和磁层,以及十几个地球半径以外的行星际的空间环境参数。它将为我国各类用户提供完整、连续、可靠的多学科、多层次的空间环境地基综合监测数据。子午工程总投资1.67亿元,建设期3年,子午工程整体科学寿命预计超过11年。 相似文献
980.
龙滩库区蓄水初期水库诱发地震活动分析 总被引:2,自引:2,他引:0
龙滩水利枢纽位于广西天峨,是一座典型高坝大库容水库。本文通过对库区及周围的地质构造和蓄水前后地震活动分析,总结了龙滩水库蓄水初期诱发地震的时间、空间和深度分布特征以及蓄水后库区水位变化与地震活动关系,讨论了龙滩库区蓄水初期诱发地震机理。 相似文献