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Snoke震源机制求解方法应用研究 总被引：2，自引：1，他引：1
通过2003年青海德令哈M_L 6.7地震序列的主震和3个不同震级的余震震源机制解测定实例,展示了Snoke(2003)震源机制求解方法的应用过程和结果,提出了应用该方法需注意的问题。将同时利用了P波和S波初动方向及振幅比数据的测定结果与仅用P波初动方向数据的结果作了对比研究,说明仅用P波初动方向常常不能有效约束震源机制解,而Snoke方法增加使1用的SH波和SV波的初动方向以及SH波、SV波与P波的观测振幅比数据,使解答得到了更有效的约束,提高了解答的可信度。本试验研究说明,基于区域性的宽频带数字地震记录,利用Snoke震源机制求解方法,有可能测定出比较可靠的中、小地震的震源机制解。 相似文献
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利用云南数字地震台网记录的区域波形资料,用P、S波初动和P、S波的振幅比联合计算了发生在云南省内的91次中小地震的震源机制.通过与矩心矩张量法和P波初动法的结果对比分析,认为用P、S波初动和振幅比求解震源机制的方法是可行可靠的,用这种方法不仅可以得到5级以上地震的震源机制,也可以计算台网分布较好地区的3～4级地震的震源机制.另外,用91个地震的震源机制资料得到了云南地区震源机制类型、主压应力轴的平面分布及其统计图,结果表明云南地区以走滑型地震为主,主压应力轴优势分布方向为NNE向,这些结果与利用哈佛得到的结果是一致的. 相似文献
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采用点源位错模型、层状介质速度结构,利用地震波垂直向记录的直达P珔、S珔波最大振幅,计算小地震震源机制。通过系统聚类,利用矢量合成方法,计算得到各类解的平均震源机制解。采用上述方法,针对2003年以来新疆北天山西段和中天山地区4次中强地震前,震源区周围中小地震震源断错性质和P轴方位的变化进行分析。结果显示,中强地震前2～3年中小地震震源机制解类型随机分布,震前1年表现出明显的优势分布特点,主压应力P轴方位发生较明显的偏转变化。 相似文献
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岫岩5.4级地震前后振幅比变化特征 总被引：3，自引：0，他引：3
1999年11月29日，辽宁省岫岩发生了Ms5．4地震，本文研究了该地震前后岫岩、营口、丹东、本溪、宽甸、东陵六个数字化地震台记录的数字地震波振幅比的变化特征。并通过分析S波、P波振幅关系探讨了岫岩地震前后震源机制的变化。结果表明：岫岩5．4级地震前，营口、本溪、丹东、东陵四个台在震前都出现低值异常现象；岫岩5．1级地震前，岫岩、本溪、丹东、东陵四个台震前均出现低值现象。岫岩5．4级前震序列P波最大振幅与S波最大振幅显示出较好的线性关系，但余震序列P波最大振幅与S波最大振幅则较为离散，呈非线性关系。 相似文献
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本文提出了体波单震相测定震源机制的方法。按理论地震图公式，直达Ｐ波和Ｓ波地表垂直分量位移由地震矩，震源幅射和介质响应之积组成。我们将其变换成地震矩，假定断裂参数的单位地震矩单震相理论子波和待守断裂参数与假定断裂参数辐射函数之商的乘积，在各台理论与实际体波单震相最大振幅的最小二乘法中求解出震源参数，利用ＣＤＳＮ数字台网资料，我们分析了青海共和地震的震源机制。结果表明，１９９０年４月２６日Ｍｓ＝６．７ 相似文献
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Carrick M. Eggleston 《Aquatic Sciences - Research Across Boundaries》1993,55(4):240-249
Scanning tunneling microscopy (STM) is used to observe, at the atomic scale, Cr(III) adsorbed to hematite (001) surfaces from aqueous solution. The Cr(III) adsorbates are relatively immobile, but estimated activation energies for surface self-diffusion are lower than those for water or hydroxyl substitution in aqueous Cr(III). Possible causes are effects of STM imaging (artifacts), high ligand-substitution rates for adsorbed species, or participation of substrate Fe (III) ligand exchange. STM imaging of suitable aqueous surface complexes is shown to be feasible, and constitutes a new way to study the relationships between microscopic and macroscopic chemical behavior of adsorbed species in aqueous systems. 相似文献
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I. A. Ansari 《洁净——土壤、空气、水》1987,15(2):175-178
This paper deals with the toxicity of sodium nitrite to freshwater fishes, Channa punctatus (BL.) and Mystus (M). vittatus (Bl.) as to determine the acute toxicity. The LC 50 values were obtained by using a static bioassay method for a period of 24, 48, 72 and 96 hour intervals. The LC 50 values of sodium nitrite for C. punctatus were 375, 325, 250 and 200 ppm and for M. (M). vittatus 164, 140, 90 and 64 ppm, respectively. A profuse mucus secretion was evident at higher concentrations as compared to lower ones. The probable causes of mortality of the fishes are also discussed. 相似文献
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《国际泥沙研究》2018,(4)
正Editing Board address:IRTCES, 20 West Chegongzhuang Rd., Beijing 100048, China IJSR is the journal of THE WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH (WASER) and is edited by the International Research and Training Center on Erosion and Sedimentation (IRTCES).Main topics:Fluvial and estuarine processes 相似文献
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Recent evaluations of acute and chronical toxicity of arsenic resulted in a reduction of the standard value for total arsenic from 40 μg/L to 10 μg/L in drinking water which will be valid in Germany after a transition period as from January 1996. Arsenic is well known as substance of deep groundwaters, mainly of geogenic origin and normally found as As(III) or As(V). As(V) is well removable by flocculation and filtration after adding iron salts. As(III), however, has to be oxidized first to As(V). Therefore, it is important for treatment techniques to be able to distinguish between As(III) and As(V). A modified determination of As(III) using flow injection analysis was installed and optimized in order to investigate whether As(III) may be oxidized to As(V) by bacteria in natural waters. The results showed that at 4°C, no As(III)-oxidation was observed within 14 days. At room temperature, however, in the bacteria-containing samples, an As(III)-oxidation was found starting after 3 to 7 days. After 14 days, no As(III) was left over. In contrast, in the sterile samples, no As(III)-oxidation could be observed within 14 days. These results demonstrated that microbial processes influence the oxidation of As(III) to As(V) in natural waters. 相似文献
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通过对云南抚仙湖沉积物柱芯样品的~(210)Pb、~(137)Cs和~(241)Am测试表明,柱芯剖面上有明显的1963年和1986年~(137)Cs蓄积峰,验证了1975年次级蓄积峰存在的可能性,这些峰形完好的蓄积峰对抚仙湖的现代沉积环境有明显的时标意义。利用~(137)Cs计年法得到抚仙湖沉积物自1963年、1975年及1986年以来到2007年的平均沉积速率分别为0.063g/(cm~2·a)、0.052g/(cm~2·a)和0.039g/(cm~2·a),说明了过去近五十年抚仙湖沉积速率整体上经历了一个由快到慢的过程。借助于~(241)Am的1963年蓄积峰可以提高~(137)Cs计年的准确性。根据~(210)Pb CRS计年模式,计算出每个样品深度所对应的年代,与~(137)Cs计年法比较存在一定的偏差,分析了两种计年方法存在差异性的原因。通过质量深度和年代分析,抚仙湖的沉积速率变化幅度比较大,表明抚仙湖近129年来的沉积环境不稳定,可能与相应历史时期的人类活动有密切的关系。 相似文献
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Zare MR Mostajaboddavati M Kamali M Abdi MR Mortazavi MS 《Marine pollution bulletin》2012,64(9):1956-1961
The natural radioactivity levels in sediment samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz canyon to Goatr seaport, as the first time has been determined. The results of measurements will serve as background reference level for Oman Sea coastlines. Sediments from 36 coastal and near shore locations were collected for analysis. Analysis on the collected samples were carried out to determine (235)U, (238)U, (232)Th, (40)K and (137)Cs using two high purity germanium detectors with 38.5% and 55% relative efficiencies. The concentration of (235)U, (238)U, (232)Th, (40)K and (137)Cs in sediment samples ranged between 1.01 and 2.87Bq/kg, 11.83 and 22.68Bq/kg, 10.7 and 25.02Bq/kg, 222.89 and 535.07Bq/kg and 0.14 and 2.8Bq/kg, respectively. The radium equivalent activity was well below the defined limit of 370Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. 相似文献
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The application of a magnetotelluric surveying method, developed specifically for detection of strong conductivity contrasts, has permitted interpretations of the deep structure of two important volcanic formations in the Canary Archipelago: the Timanfaya (Lanzarote) and Teide (Tenerife) volcanoes. Beneath the Timanfaya volcano, a highly conductive body (p ≤ 1 Ω m) has been detected, which is interpreted as a shallow magma chamber associated with the eruption which took place between the years 1730 and 1736. The core of this intrusion, still largely molten, would be located at approximately 4 km depth and would still maintain temperatures in excess of 900 °C.In the Telde caldera the asymmetry of the apparent resistivity components indicates a double depression; furthermore, a highly conductive level encountered in the centre of the eastern part of the volcanic complex has been attributed to the persistance of relatively high temperatures in the root of the last salic dome, extruded inside the caldera. In both zones, the deep limiting horizon is a highly conductive layer corresponding to the mantle (15 km in Lanzarote and 13 km in Tenerife), whereas other, more superficial, discontinuities have been related to local structures. 相似文献