基于不同设定地震方法的长周期建筑设计反应谱的对比分析

现有的设定地震方法主要有两种：加权平均法和最大概率法。本文首先简要介绍了这两种方法,然后以烟台地区一高层建筑为研究对象,分别采用加权平均法和最大概率法进行地震危险性分析,确定出设定地震震级、震中距以及具体空间位置,给出了两种方法的设定地震反应谱,最后对这两种方法所得结果的差异进行了对比和分析。结果表明：加权平均法所得反应谱将长周期处的安全性考虑在内,适用于中长周期建（构）筑物;最大概率法由于其长周期处谱值偏低,会增加长周期工程的危险性,不宜用于长周期工程,但对短周期建（构）筑物应用合理;对于自振周期不同的建筑工程应选用不同的地震危险性分析方法进行设计反应谱的确定。     

对含厚软表层海域工程场地设计地震动参数确定的一点建议

工程上常用的等效线性化方法在处理常见的、含厚软表层的海域场地时,其计算结果往往产生较大的偏异.为了研究这些计算偏异产生的程度,本文利用等效线性化方法对典型海域工程钻孔进行了小震、中震和大震3种不同工况下保留和舍弃软表层情况下的土层计算.考虑到在大震作用下,土体可能进入大的非线性范围,等效线性化将不再适用,故引入了一种能更好地考虑土层大非线性效应的直接时域积分方法,并与等效线性化方法研究结果进行了对比分析.在此基础上,给出了确定含厚软表层海域工程场地设计地震动参数的处理建议.     

东北地震区小震资料完整性分析及其对地震活动性参数的影响研究

以东北地震区为例,基于G-R关系的震级-频度分布原理,研究了东北地震区最小完整性震级MC的时间分布特征和各时段的空间分布特征,统计了研究区内的地震活动性参数,探讨了小震资料完整性分析对地震活动性参数和地震危险性计算结果的影响。研究表明：对区域小震资料进行完整性分析,可以在低地震活动地区获得较准确的地震活动性参数,更好地反映了该区未来的地震活动趋势。本文的研究方法和结论可供地震资料完整性分析和地震活动性分析时参考。     

考虑地震构造背景的地震活动性参数光滑方法在地震危险性概率评价中的应用

In this study, the North China seismic region was selected as the study area, and evaluation of seismic hazard using the spatial smoothing seismicity model was performed. Firstly, the study area is divided into grids, and some parameters (e.g. b-value, M0, Mu, azimuth and M-L relationship) for each seismotectonic model were assigned. Secondly, using elliptical smoothing based on a seismotectonic background model, the statistical earthquake incidence rate in each grid is successively calculated. Lastly, the relevant ground motion attenuation relationship is chosen to assess seismic hazard of general sites. The maps for the distribution of horizontal peak ground acceleration with 10% probability of exceedance in 50 years were obtained by using the seismic hazard analysis method based on grid source. This seismicity model simplifies the methodology of probabilistic seismic hazard analysis, especially appropriate for those places where seismic tectonics is not yet clearly known. This method can provide valuable references for seismic zonation and seismic safety assessment for significant engineering projects.     

对于“Stuart Crampin对Jordan等‘可操作性地震预报:发展现状和使用手册[2011]’评论”的回复

在对国际地震预报委员会(ICEF)报告[1]的评论中,Crampin[2]声称剪切波分裂变化可以在短时间尺度上预测地震,并且可靠性高,技术性强.他对ICEF的一个重要发现提出挑战——到目前为止,没有任何方法具有如此高的预测能力.特别是,Crampin宣称,在意大利中部三孔应力监测站点(SMS)剪切波分裂观测可以监测SMS1000 km以内的所有破坏性地震(M≥5)前的应力积累和应力释放(裂缝贯通).     

Formation mechanism of a rainfall triggered complex landslide in southwest China

This case study is about a landslide that occurred after 4 days of heavy rainfall,in the morning of June 29,2012,in Cengong County,Guizhou Province of China,geographical coordinated 108°20′-109°03′E,27°09′-27°32′N,with an estimated volume of 3.3×106 m3.To fully investigate the landslide process and formation mechanism,detailed geotechnical and geophysical investigations were performed including borehole drilling,sampling,and laboratory tests coupled with monitoring of displacement.Also,a combined seepage-slope stability modeling was performed to study the behavior of the landslide.After the heavy rainfall event,the sliding process started in this area.The landslide development can be divided into different parts.The man-made fill area,spatially distributed in the south side of the landslide area with low elevations,slid first along the interface between the slope debris and the strongly weathered bedrock roughly in the EW direction.Consequently,due to severe lateral shear disturbance,the slope in the main sliding zone slid next towards the SW direction,along the sliding surface developed within the strongly weathered calcareous shale formation located at a depth of 25-35 m.This means it was a rainfall triggered deep-seated landslide.Finally,retrogressive failure of a number of upstream blocks occurred,which moved in more than one direction.The initial failure of the man-made fill area was the‘engine’of the whole instability framework.This artificial material with low permeability,piled up in the accumulation area of surface and sub-surface and destroyed the drainage capacity of the groundwater.The numerical modeling results agreed with the analysis results obtained from the laboratory and field investigations.A conceptual model is given to illustrate the formation mechanism and development process of the landslide.     

Opportunities to search for extraterrestrial intelligence with the FAST

The discovery of ubiquitous habitable extrasolar planets,combined with revolutionary advances in instrumentation and observational capabilities,has ushered in a renaissance in the search for extraterrestrial intelligence(SETI).Large scale SETI activities are now underway at numerous international facilities.The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the largest single-aperture radio telescope in the world,and is well positioned to conduct sensitive searches for radio emission indicative of exo-intelligence.SETI is one of the five key science goals specified in the original FAST project plan.A collaboration with the Breakthrough Listen Initiative was initiated in 2016 with a joint statement signed both by Dr.Jun Yan,the then director of National Astronomical Observatories,Chinese Academy of Sciences(NAOC),and Dr.Peter Worden,Chairman of the Breakthrough Prize Foundation.In this paper,we highlight some of the unique features of FAST that will allow for novel SETI observations.We identify and describe three different signal types indicative of a technological source,namely,narrow band,wide-band artificially dispersed and modulated signals.Here,we propose observations with FAST to achieve sensitivities never before explored.For nearby exoplanets,such as TESS targets,FAST will be sensitive to an EIRP of 1.9×1011 W,well within the reach of current human technology.For the Andromeda Galaxy,FAST will be able to detect any Kardashev type II or more advanced civilization there.     

矿物收藏漫谈(五) 这些矿物杂志和书籍,实在精彩

<正>上期中提到了一些关于矿物标本的书籍,这里再列出几本实在精彩的有关矿物收藏知识的书籍和杂志,因为他们实在是精彩。     

2008年3月4日台湾东北部两次TAIGER爆破记录的地面旋转和平移运动

2008年3月4日在台湾东北部的N3爆破点实施了两次爆破。第一次3000kg炸药的爆破编号为N3P,第二次750kg炸药的爆破编号为N3。为了记录这两次爆破,我们使用了8个三轴旋转传感器、13个三轴加速度计以及12个装有全球定位系统接收器的6通道24位数据记录仪在爆破前后几小时进行连续观测。这些仪器安装在距离爆破点250m(1个台)、500m(11个台)、600m(1个台)的地方,其中距离爆破点500m的11个台站形成了台站间距约为5m的中心台阵。除一个旋转传感器外,都得到了量程内的记录。尽管N3P爆破使用的炸药是N3爆破的4倍,但是13个台站记录的N3P爆破的平移加速度和旋转速度的峰值却只有N3爆破的1.5倍。在台站间距大约5m的中心台阵的记录中,我们还发现平移加速度和旋转速度变化很大(百分之几十)。N3P和N3爆破的最大峰值旋转速度分别为2.74mrad/s和1.75mrad/s。本文的主要目的是报告台湾这两次爆破的旋转和平移运动记录,并在网上发布以开放访问。Langston等(2009)已经对本次试验的平移加速度数据进行了分析,我们计划未来发表一篇关于分析旋转速度数据的文章。     

Isolation and characterization of two crude oil-degrading yeast strains, Yarrowia lipolytica PG-20 and PG-32, from the Persian Gulf

Among six crude oil-degrading yeasts that were isolated from an oil-polluted area in the Persian Gulf, two yeast strains showed high degradation activity of aliphatic hydrocarbons. From an analysis of 18S rRNA sequences and biochemical characteristics, these strains were identified as Yarrowia lipolytica strains PG-20 and PG-32. Gas Chromatography (GC) analysis of the crude oil remaining in the culture medium after 1 week at 30°C showed that the strains PG-20 and PG-32 degraded 68% and 58% of crude oil, respectively. The optimal growth condition and biodegradation of hydrocarbons was in ONR medium with an acidic pH (pH5). These two strains may degrade aliphatic hydrocarbons more efficiently than aromatic hydrocarbons, although strain PG-20 had better degradation than strain PG-32. The two Y. lipolytica strains reduce surface tension when cultured on hydrocarbon substrates (1% v/v). These strains showed a cell surface hydrophobicity higher than 70%. These results suggested that Y. lipolytica strains PG-20 and PG-32 have high crude oil degrading activity due to their high emulsifying activity and cell hydrophobicity. In conclusion, these yeast strains can be useful for the bioremediation process in the Persian Gulf and decreasing oil pollution in this marine ecosystem.