Estimation of source parameters of Chamoli Earthquake, India     

Y. Pandey  R. Dharmaraju  P. K. S. Chauhan 《Journal of Earth System Science》2001,110(2):171-177

The devastating earthquake (mb = 6.6) at Chamoli, Garhwal Himalaya, which occurred in the morning hours on 29th March 1999, was recorded on Delhi Strong Motion Accelerograph (DSMA) Network operated by the Central Building Research Institute, Roorkee. In this paper the source parameters of this event calculated from the Strong Motion Data are presented. The seismic moment for this event has been found to be of the order of 10²⁵ dyne.cm and the moment magnitude has been calculated in the range of 6.53–6.69 at different stations. The stress drop and source radius for the earthquake are also calculated.  相似文献   

关于震级频度关系的一些讨论   总被引：1，自引：1，他引：1  

陈时军  王丽凤  马丽  张红军 《地震学报》2002,24(2):176-185

讨论了地震活动的复杂性特征与震级频度的关系．认为一般情况下地震活动系统具有多重分形特征．文中利用多重分形的观点讨论了震级频度关系的形式，分析了震级频度关系出现非线性的可能的原因．作为示例，文中概要地讨论了新西兰近年来的地震活动bq谱．   相似文献   

青海昆仑山口西8.1级地震时空强有序特征探讨   总被引：6，自引：0，他引：6       下载免费PDF全文

张晓东  张永仙  吕梅梅  余素荣 《地震学报》2003,25(6):583-590

通过对2001年11月14日昆仑山口西8.1级地震的时间、空间、强度和触发特征的分析和初步研究认为，昆仑山口西8.1级地震在时间上具备时间节律的特征，符合8级地震24年左右和7级以上地震7年左右的时间节律关系；在空间上存在地震活动等间距、地震集中活动、共轭条带等特征；在强度上符合节律特征，并存在明显地受地球自转，以及月亮、太阳的调制和触发作用. 最后，对巨大地震孕震和发震的条件进行了讨论．   相似文献   

有关科里奥利力效应与昆仑山口西8.1级地震余震活动趋势的讨论s   总被引：3，自引：0，他引：3       下载免费PDF全文

吕坚  高建华  刘吉夫  胡翠娥  黄双凤 《地震学报》2003,25(4):432-440

根据物理学中的科里奥利力定义和计算原理，在对中国大陆20次7.5级以上特大地震余震强度与科里奥利力效应关系的统计研究基础上，重点对2001年11月14日昆仑山口西8.1级地震时所受到的科里奥利力情况进行了研究，并以此来讨论该地震后期的余震活动趋势．结果表明: ① 利用科里奥利力效应预测中国大陆特大地震的余震强度是一个有效的方法．对于左旋走滑断层和上盘错动方向通过震源子午面右侧（向北看）的逆断层，其科里奥利力效应是使断层两盘相互拉离，它降低了断层错动时断层面上的摩擦阻力，地震能量主要在主震时充分释放，故余震强度小；对于右旋走滑断层，其科里奥利力效应是使断层两盘相互挤压，它增加了断层错动时断层面上的摩擦阻力，不利于主震能量的充分释放，所以余震强度大；② 2001年11月14日昆仑山口西8.1级地震的发震断层错动以左旋走滑为主，受到的科里奥利力使断层两盘相互拉离，大小约为0.06 MPa．经过类比分析后认为，该地震后期的余震活动水平不会太高，整个序列的最大余震震级估计为6级左右．   相似文献   

岩石非均匀性对震级—频度关系的影响的数值模拟   总被引：1，自引：0，他引：1  

梁正召  唐春安  朱万成  杨天鸿  王善勇 《地震研究》2003,26(2):151-155

无论是从天然地展的统计分析还是实验室岩石破裂实验，由于测试设备的限制、观测台站或测试位置的影响，目前有关地展展级-频度关系和G—R关系式及b值的研究都不可能保证数据资料的独立性和完整性。充分利用RFPA^20数值模拟软件，克服漏记、精度低和人为的限定资料范围等不利因素的影响，在充分考虑岩石的非均匀性的基础上，研究了岩石破裂过程中微震系列震级-频度关系及b值随岩石均质度的变化规律。  相似文献   

宁波ZK03井水温异常与昆仑山口西8.1级地震的关系   总被引：12，自引：0，他引：12  

邱永平 《内陆地震》2003,17(2):141-144

通过分析宁波台ZK03井的基本观测条件、所使用的仪器设备以及对其日均值、整点值的探讨，认为该井水温异常很可能与昆仑山口西8．1级地震有关系。从日均值图上看，异常出现在震前10天左右，最大异常量为正常速率的负20倍；从整点值图上看，震前10天开始在34个小时内测值下降了0．001℃，是正常速率的负18倍。异常出现原因可能是由于地震前的长周期波通过上地幔或软流层传播，间接地导致了地下流体温度发生了微小的变化。  相似文献   

新疆巴楚-伽师6.8级地震序列及震情分析     

高国英  王筱荣  曲延军 《内陆地震》2003,17(2):170-175

2003年2月24日新疆巴楚—伽师发生6．8级地震，震中位于1997—1998年伽师9次6级地震分布区域的东南端。这次6．8级地震的余震呈北西向分布，与极震区长轴走向一致，截止2003年4月15日最大余震为5．8级。震源机制解初步分析结果为：震源断错属逆倾滑性质，近南北向的节面可能为主破裂面，主压应力P轴方位为北西西。6．8级地震发生在2003年度全国划定的6—7级地震危险区内。震前根据新疆震情的发展，新疆地震局预报中心在对2月份的震情判定中明确提出“2月或稍长时间新疆两个地震重点危险区有发生中强震的可能”，预测意见对应较好。  相似文献   

Accurate and High‐Precision Determination of Boron Isotopic Ratios at Low Concentration by MC‐ICP‐MS (Neptune)     

Catherine Guerrot  Romain Millot  Michèle Robert  Philippe Négrel 《Geostandards and Geoanalytical Research》2011,35(2):275-284

We report an approach for the accurate and reproducible measurement of boron isotope ratios in natural waters using an MC‐ICP‐MS (Neptune) after wet chemistry sample purification. The sample matrix can induce a drastic shift in the isotopic ratio by changing the mass bias. It is shown that, if no purification is carried out, the direct measurement of a seawater diluted one hundred times will induce an offset of ?7‰ in the isotopic ratio, and that, for the same concentration, the greater the atomic mass of the matrix element, the greater the bias induced. Whatever the sample, it is thus necessary to remove the matrix. We propose a method adapted to water samples allowing purification of 100 ng of boron with a direct recovery of boron in 2 ml of 3% v/v HNO₃, which was our working solution. Boron from the International Atomic Energy Agency IAEA‐B1 seawater reference material and from the two groundwater reference materials IAEA‐B2 and IAEA‐B3, was chemically purified, as well as boron from the certified reference material NIST SRM 951 as a test. The reproducibility of the whole procedure (wet chemistry and MC‐ICP‐MS measurement) was ± 0.4‰ (2s). Accuracy was verified by comparison with positive‐TIMS values and with recommended values. Seawater, being homogeneous for boron isotope ratios, is presently the only natural water material that is commonly analysed for testing accuracy worldwide. We propose that the three IAEA natural waters could be used as reference samples for boron isotopes, allowing a better knowledge of their isotopic ratios, thus contributing to the certification of methods and improving the quality of the boron isotopic ratio measurements for all laboratories.  相似文献   

Chemical Characterization of Carbonated Natural Mineral Waters Produced in Turkey: Compliance with European Water Quality Standards     

Cüneyt Güler  Musa Alpaslan 《洁净——土壤、空气、水》2011,39(11):947-955

In this study, a total of 100 samples from 25 brands of carbonated natural mineral waters (CNMWs) produced in Turkey were analyzed for a total of 36 water quality constituents to determine their suitability for human consumption. Parameters examined include pH, electrical conductivity, ammonia, nitrate, nitrite, sulfate, sulfite, orthophosphate, chloride, fluoride, bicarbonate, and 25 major/trace elements analyzed by inductively coupled plasma‐mass spectrometry (ICP‐MS). The presence of these constituents in this type of water was investigated considering recent concerns about their quality and the lack of trace element information on the manufacturer labels. The analytical results obtained in this study were compared to the European Union (EU) norms, labeled values on bottles, as well as values from the literature. Results of this study have shown that Turkish CNMWs may contain high concentrations of sulfite, which is a known allergen, especially for chronic asthmatic population. CNMWs surveyed in this study have also appreciable amounts of fluoride (>1.5 mg L^?1) that may have detrimental effects on health of children. The EU standards for As, Ba, Mn, and Ni were exceeded in seven CNMWs classified as “high mineral”. Compared to similar type of bottled waters from Europe and North America, CNMWs from Turkey generally contained higher elemental concentrations.  相似文献   

A new prototype system for earthquake early warning in Taiwan   总被引：1，自引：0，他引：1  

Nai-Chi Hsiao  Yih-Min Wu  Li Zhao  Da-Yi Chen  Wei-Ting Huang  Kuan-Hung Kuo  Tzay-Chyn Shin  Peih-Lin Leu 《Soil Dynamics and Earthquake Engineering》2011

A new prototype earthquake early warning (EEW) system is being developed and tested using a real-time seismographic network currently in operation in Taiwan. This system is based on the Earthworm environment which carries out integrated analysis of real-time broadband, strong-motion and short-period signals. The peak amplitude of displacement in the three seconds after the P arrival, dubbed P_d, is used for the magnitude determination. Incoming signals are processed in real time. When a large earthquake occurs, P-wave arrival times and P_d will be estimated for location and magnitude determinations for EEW purpose. In a test of 54 felt earthquakes, this system can report earthquake information in 18.8±4.1 s after the earthquake occurrence with an average difference in epicenter locations of 6.3±5.7 km, and an average difference in depths of 7.9±6.6 km from catalogues. The magnitudes approach a 1:1 relationship to the reported magnitudes with a standard deviation of 0.51. Therefore, this system can provide early warning before the arrival of S-wave for metropolitan areas located 70 km away from the epicenter. This new system is still under development and being improved, with the hope of replacing the current operational EEW system in the future.  相似文献