形变观测预报地震模式的探讨     

王秀文  宋美琴  李媛媛  程紫燕  张瑞芳 《山西地震》2007,(3):1-6

总结了用形变观测项目进行地震分析预报的经验和方法,对观测曲线的形态及异常显示、断层活动性质、地震异常识别、异常与震中的关系、异常与震级的关系、断层位移与地应力变化、预报指标进行了研究,以对今后的地震预报工作提供一定的参考。  相似文献   

Source parameters of intermediate-depth Vrancea (Romania) earthquakes from empirical Green's functions modeling     

Adrien Oth  Friedemann Wenzel  Mircea Radulian 《Tectonophysics》2007,438(1-4):33-56

Several source parameters (source dimensions, slip, particle velocity, static and dynamic stress drop) are determined for the moderate-size October 27th, 2004 (M_W = 5.8), and the large August 30th, 1986 (M_W = 7.1) and March 4th, 1977 (M_W = 7.4) Vrancea (Romania) intermediate-depth earthquakes. For this purpose, the empirical Green's functions method of Irikura [e.g. Irikura, K. (1983). Semi-Empirical Estimation of Strong Ground Motions during Large Earthquakes. Bull. Dis. Prev. Res. Inst., Kyoto Univ., 33, Part 2, No. 298, 63–104., Irikura, K. (1986). Prediction of strong acceleration motions using empirical Green's function, in Proceedings of the 7th Japan earthquake engineering symposium, 151–156., Irikura, K. (1999). Techniques for the simulation of strong ground motion and deterministic seismic hazard analysis, in Proceedings of the advanced study course seismotectonic and microzonation techniques in earthquake engineering: integrated training in earthquake risk reduction practices, Kefallinia, 453–554.] is used to generate synthetic time series from recordings of smaller events (with 4 ≤ M_W ≤ 5) in order to estimate several parameters characterizing the so-called strong motion generation area, which is defined as an extended area with homogeneous slip and rise time and, for crustal earthquakes, corresponds to an asperity of about 100 bar stress release [Miyake, H., T. Iwata and K. Irikura (2003). Source characterization for broadband ground-motion simulation: Kinematic heterogeneous source model and strong motion generation area. Bull. Seism. Soc. Am., 93, 2531–2545.] The parameters are obtained by acceleration envelope and displacement waveform inversion for the 2004 and 1986 events and MSK intensity pattern inversion for the 1977 event using a genetic algorithm. The strong motion recordings of the analyzed Vrancea earthquakes as well as the MSK intensity pattern of the 1977 earthquake can be well reproduced using relatively small strong motion generation areas, which corresponds to small asperities with high stress drops (300–1200 bar) and high particle velocities (3–5 m/s). These results imply a very efficient high-frequency radiation, which has to be taken into account for strong ground motion prediction, and indicate that the intermediate-depth Vrancea earthquakes are inherently different from crustal events.  相似文献   

安徽和县香泉独立铊矿床铊的赋存状态研究     

范裕周涛发  袁峰吴明安  张千明侯明金　胡清华 《岩石学报》2007,23(10):2530-2540

分散元素铊成矿作用的相关研究近年来已经取得了重要进展,但矿床中铊的赋存状态研究仍有待深入.香泉独立铊矿床位于长江中下游成矿带北侧的皖东地区,该矿床中铊的赋存状态研究对拓展铊元素成矿研究具有重要意义.本文通过矿相学、微量元素地球化学、电子探针分析和X射线粉晶分析等方法,确定了香泉铊矿床中黄铁矿是铊的主要载体矿物.铊在黄铁矿中主要以类质同象形式替代铁进入黄铁矿晶格,其次以纳米级、次纳米级铊矿物颗粒形式产出.  相似文献   

一次暴雨过程的EOF分析   总被引：1，自引：1，他引：1  

张铭  安洁  朱敏 《大气科学》2007,31(2):321-328

在用21层η坐标细网格模式对1998年7月21～22日发生在武汉地区的一次持续性特大暴雨过程数值模拟的基础上， 利用较高时空分辨的模式输出结果对暴雨过程做经验正交函数分解（EOF分析）尝试。结果表明:EOF第1主分量的空间分布代表典型的暴雨环境背景场的低值系统；EOF第2主分量的空间分布与人字形切变线（西部为冷式切变，东部为暖式切变）相联系，是影响这次暴雨的重要形势场；利用相轨线分析方法发现，暴雨过程中EOF第1主分量和EOF第2主分量的时间系数在暴雨临近阶段，两者正相关，激发暴雨，在暴雨后期两者负相关，促使这次暴雨趋于减弱结束。  相似文献   

The regional dynamical model of the atmospheric ozonosphere   总被引：1，自引：0，他引：1  

Wang Weiguo  Xie Yingqi  Qiu Jinhuan  Liu Qing 《大气科学进展》1998,15(1):74-82

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Using regional regression within index flood procedures and an empirical Bayesian estimator     

Heinz D. Fill  Jery R. Stedinger 《Journal of Hydrology》1998,210(1-4):128-145

Studies have illustrated the performance of at-site and regional flood quantile estimators. For realistic generalized extreme value (GEV) distributions and short records, a simple index-flood quantile estimator performs better than two-parameter (2P) GEV quantile estimators with probability weighted moment (PWM) estimation using a regional shape parameter and at-site mean and L-coefficient of variation (L-CV), and full three-parameter at-site GEV/PWM quantile estimators. However, as regional heterogeneity or record lengths increase, the 2P-estimator quickly dominates. This paper generalizes the index flood procedure by employing regression with physiographic information to refine a normalized T-year flood estimator. A linear empirical Bayes estimator uses the normalized quantile regression estimator to define a prior distribution which is employed with the normalized 2P-quantile estimator. Monte Carlo simulations indicate that this empirical Bayes estimator does essentially as well as or better than the simpler normalized quantile regression estimator at sites with short records, and performs as well as or better than the 2P-estimator at sites with longer records or smaller L-CV.  相似文献   

Notions of justice held by stakeholders of the Newfoundland fishery     

《Marine Policy》2015

Justice is an important and contested issue in the governance of fish stocks threatened by overexploitation. This study identifies the notions of justice held by stakeholders of the fishery in Newfoundland, Canada, using qualitative interviews, and interprets these notions in light of established justice theories. The interviews are analysed using inductive and deductive coding. A central result is that inshore fishers are seen as the main claim holders, with a claim to participate and be listened to, and the opportunity to make a living from the fishery. Moreover, rules play an important role in the justice notions of the interview partners, and their justice notions are clearly plural. The stakeholder notions of justice in the Newfoundland fishery resonate with the emphasis on recognition, participation and distribution as important aspects of justice within the environmental justice approach [59-61] (Schlosberg 2004, 2007, 2013).  相似文献   

Deterministic and ensemble storm surge prediction for Atlantic Canada with lead times of hours to ten days     

《Ocean Modelling》2015

Regional deterministic and ensemble surge prediction systems (RDSPS and RESPS respectively) are used to forecast sea levels off the east of Canada and northeast US. The surge models for the RDSPS and RESPS have grid spacings of 1/30° and 1/12° respectively. The models are driven by surface air pressure and 10 m winds generated by operational global deterministic and ensemble prediction systems that are run operationally by the Canadian Meteorological Centre. Surge forecasts are evaluated for the period 1 March, 2013 to 31 March 2014. Based on traditional statistics (e.g., standard deviation of the difference between observations and predictions) both systems are shown to have skill in forecasting surges six days into the future. It is shown however that skill exists beyond six days if allowance is made for errors in the timing of large surges. The usefulness of the RESPS is demonstrated for two positive surges (important for coastal flooding and erosion) and a negative surge (important for safe navigation in shallow water). It is shown that the RESPS can identify events not forecast by the RDSPS, and can also add useful additional information on the timing of the surge, an important consideration in tidally dominated waters. Several new types of display are used to illustrate the sort of information that can be generated by the RESPS to support the issuers of warnings of unusually high and low total water levels.  相似文献   

经验模态分解方法在树木年轮宽度序列标准化中的应用     

张永 《沙漠与绿洲气象(新疆气象)》2015,9(5):9-15

高分辨率的树木年轮是记录历史时期气候变化的良好生物载体,在古气候研究中被广泛应用。但年轮宽度与气候因子之间有着复杂的联系,这种关系受气候因子之间的相互制衡和因物种而异的树木生长节律的共同影响。在利用树木年轮开展历史时期气候变化的研究中,剔除树木年轮与年龄相关的生长趋势是准确获取气候信号的先决条件。然而,传统的和相对改进的一些树轮标准化方法在拟合并剔除树龄相关的趋势及非气候干扰信息方面仍存在一些问题。本文利用经验模态分解(EMD)方法进行树轮资料的标准化方法研究, 对已获得的树轮生长序列所记录的信息进行分解,得到一系列不同物理意义的本征模态分量,结合多样本信息的对比及生物学特性,深入解读各分量表征的气候变化、环境干扰及缓慢生长趋势项等不同物理意义,进而剔除非气候信息,得到可以准确反映气候变化的代用序列,并将该方法与目前广泛采用的标准化方法进行对比,分析不同方法的利弊所在,为进一步改进树轮标准化方法提供新思路。  相似文献   

南大洋淡水强迫对南半球环状模的影响分析   总被引：1，自引：0，他引：1  

马浩  李正泉  冯涛  刘成彦 《气象与环境学报》2015,(3):81-88

南半球环状模是南半球热带外大气环流变异的主导模态,对南半球海洋—大气—海冰耦合系统有重要的影响。冰川融化激发的淡水强迫是南大洋的一种重要外强迫。在历史气候记录中,南大洋淡水通量异常曾引发数次全球性气候异常事件。基于海—气完全耦合模式FOAM,在60°S以南的海洋中施加强度为1.0 Sv的理想化淡水通量异常,分析南半球环状模的响应。结果表明：南大洋淡水通量异常可使局地西风增强,且西风的增强在垂向各个层次上均有体现。西风强度的变化导致对流层中大气斜压性增强,平流层中大气斜压性减弱。此外,淡水强迫使环状模的年际变率振幅显著减弱,而年代际变率开始增强,谱能量的变化具有垂向一致性。海温和海冰等外强迫因子的变化对环状模年代际振幅的增强具有重要意义。  相似文献