近期天山地震带地震活动固体潮调制的统计分析

A statistical analysis is done to study the spatio-temporal features of earthquake activity in the Tianshan seismic belt triggered by tide,based on Schusters test. The data we choose is the M L≥2. 0 earthquakes from January 1,2010 to August 31,2012 in eastern Tianshan,and the calculation is on tidal body stress. The results show that the p-value based on the time window smoothing of Schusters test corresponds better with the strong earthquakes in the Tianshan seismic belt,especially for a long time before the November 1,2011 Nilka M S6. 0 earthquake,when the p-value of the Schusters test was always lower than the threshold of 0. 05 for tidal trigger of earthquake,but after the Nilka M S6. 0 earthquake,that value was quickly restored to a high level,which reflects a close relationship between the Nilka M S6. 0 earthquake and the Earth tide. According to the p-value based on the spatial window smoothing of Schusters test,the Nilka M S6. 0 earthquake was at or near the tidal triggering area. Thus we can see from the spatio-temporal results that the Nilka M S6. 0 earthquake was obviously triggered by Earth tide.     

基于粘弹库仑应力变化的后续最大地震震级估计及2008、2014年于田两次7.3级地震之间的关系讨论

在前人关于于田地区地壳水平分层模型研究的基础上,结合于田台GPS连续观测资料粗略确定各层的粘滞系数。基于粘弹水平分层模型,分别计算了2008、2014年两次于田7.3级地震的粘弹同震库仑应力变化。基于粘弹库仑应力变化,采用“直接”余震频次的计算方法,计算了区域范围内与主震同震库仑应力变化直接相关的理论地震频次。提出基于理论与实际地震频次对比以及理论与实际地震频次-距离衰减曲线拟合残差对比估计与主震同震库仑应力变化直接相关的后续最大地震震级的方法。不同方法的计算结果显示,与2008年于田7.3级地震同震库仑应力变化直接相关的最大后续地震震级为MS7.2~7.5,而2014年于田7.3级地震的估计为MS6.3。前者与2014年于田地震7.3的震级非常接近。由于震级相同、空间距离较近、时间间隔较短、区域外力作用相同、两次地震构造关联性较强且具有较明确的应力相互作用,因而认为2008、2014年两次7.3级地震构成一对广义的双震型地震,这与该区域以往序列类型特点相吻合。对震级下限及G-R关系b值对结果的影响进行了初步讨论,结果显示,当粘弹同震库仑应力变化确定之后,震级下限对后续最大地震震级估计影响不大,但G-R关系b值对结果有较大影响。     

鄂尔多斯盆地东部奥陶系风化壳储层特征及主控因素分析

鄂尔多斯盆地东部奥陶系风化壳储层岩石类型以含膏模孔的细粉晶白云岩为主。储集空间主要为溶孔,溶孔的充填程度及类型决定了储层物性的好坏。充填物类型决定储集空间的好坏,方解石充填对储集空间破坏性较大,但充填白云石由于其自身晶粒较粗,发育晶间孔,对储集空间具有建设性作用。对盆地东部风化壳储层发育的表征形态及孔洞充填物的硫同位素、化学成分、激光碳氧同位素、锶同位素特征的分析表明,盆地东部岩溶孔洞中充填的方解石主要形成于裸露风化期,而白云石则是埋藏期压释水岩溶的产物,提出中深埋藏期的压释水岩溶是有利储层形成的关键因素。     

Discussion on Earthquake Forecasting and Early Warning

Through analysis of natural and social attributes of earthquake forecasting, the relationship between the natural and social attributes of earthquake forecasting （early warning） has been discussed. Regarding the natural attributes of earthquake forecasting, it only attempts to forecast the magnitude, location and occurrence time of future earthquake based on the analysis of observational data and relevant theories and taking into consideration the present understanding of seismogeny and earthquake generation. It need not consider the consequences an earthquake forecast involves, and its purpose is to check out the level of scientific understanding of earthquakes. In respect of the social aspect of earthquake forecasting, people also focus on the consequence that the forecasting involves, in addition to its natural aspect, such as the uncertainty of earthquake prediction itself, the impact of earthquake prediction, and the earthquake resistant capability of structures （buildings）, lifeline works, etc. In a word, it highlights the risk of earthquake forecasting and tries to mitigate the earthquake hazard as much as possible. In this paper, the authors also discuss the scientific and social challenges faced in earthquake prediction and analyze preliminarily the meanings and content of earthquake early warning.     

长牡蛎Wnt5b基因的鉴定及在黑色素生成中的作用

Wnt基因家族编码一类保守的分泌型糖蛋白,广泛参与细胞分化与增殖、细胞运动、凋亡、免疫调控以及色素生成等生物学过程。本研究鉴定了一个长牡蛎Wnt家族基因——CgWnt5b,比较了黑、白壳色长牡蛎中CgWnt5b转录水平的表达情况,并对其在调控黑色素生成方面的功能进行初步研究。研究结果显示,CgWnt5b编码序列全长1116 bp,编码371个氨基酸。生物信息学分析预测CgWnt5b蛋白相对分子量为42 KDa,等电点为9.28。对CgWnt5b与哺乳动物Wnt基因家族19个成员进行系统发育分析,确定了CgWnt5b为哺乳动物Wnt5a和Wnt5b的同源基因。荧光实时定量PCR检测长牡蛎外套膜、鳃、消化腺、闭壳肌、性腺、唇瓣以及血淋巴组织中CgWnt5b的mRNA分布,结果显示,CgWnt5b在外套膜、闭壳肌和唇瓣组织中的相对表达水平较高,在消化腺、鳃、血淋巴和性腺组织中相对表达量较低。黑壳长牡蛎中CgWnt5b mRNA表达量显著低于白壳长牡蛎,且siRNA敲降CgWnt5b的表达后,多个黑色素生成相关酪氨酸酶基因的表达显著上调。综上,本研究在长牡蛎中鉴定了一个Wnt家族成员CgWnt5b,可能通过抑制黑色素生成关键基因TYR的表达抑制长牡蛎中黑色素的生成。     

大震前地震活动平静现象一种可能的机制:断层的蠕滑-匀阻化

许多大地震前地震活动存在明显的平静现象,由于其普遍性,地震平静现象被认为是具有物理意义的地震前兆并被作为地震预报的重要依据.关于大震前地震平静现象的物理机制,国内外学者从不同角度进行了研究,其中包括用破裂强度的双峰式分布、扩容硬化、震前滑动造成的应力松弛、震源体内外介质性质的差异和相互作用等机制解释强震孕育过程中短期地震活动的平静现象.尽管在一些模型中把岩石力学实验结果作为证据之一,但来自与地震活动最相似的岩石变形声发射的实验证据并不多.因为以往大量的实验结果表明,在恒定的加载条件下(等位移速率、等应力速率等),岩石破坏失稳前声发射活动多表现为加速特征,尽管一些岩石破坏前声发射活动加速现象不明显,但也难以观测到平静现象.然而,在我们开展的一系列断层结构和介质不同的中尺度标本的声发射实验中,一些标本破坏失稳前声发射活动表现出明显的相对平静现象,据此我们对大地震前地震活动平静现象的物理机制进行了讨论.     

Characteristics of the May 12,2008 Wenchuan M_S8.0 Earthquake Sequence and Discussion on Relevant Problems

The aftershock activity of the May 12, 2008 Wenchuan Ms8.0 Earthquake Sequence shows an obvious segmented feature. Most of the large aftershocks were distributed in the north and south parts of the aftershock zone. Thrusting was dominant with a small amount of strike-slip component in the south part. The aftershock activity decayed gradually, presenting the sequence features of a mainshock-aftershock pattern. The north part was the ending area of the maiushock fracture where strike-slipping was dominant, showing an obvious swarm feature. Therefore it became the major area for large aftershocks. The modulation of the earth tide on aftershock activity is remarkable; most large aftershocks occur during the period of flood and neap tide. The time period around 16:00 was the dominant occurring time for large aftershocks. The p-value, a parameter of modified Omori formula, increases gradually with time, and reaches about 1 at the end. Based on previous study, the sequence patterns, magnitude of maximum aftershock, as well as the duration of aftershock activity has been discussed. The primary results also show that the magnitude difference between the maiushockand the maximum aftershock is proportional to the rupture size of the maiushock for huge earthquakes of about Ms8.0. This means that when the magnitudes of the earthquakes are nearly the same, large rupture size corresponds to sufficient energy release.     

西非金矿床类型及时空分布规律

西非素有"黄金海岸"之称, 近年西非金矿勘查和产量不断突破新高, 已超过南非成为非洲最重要的产金区。通过系统总结西非156个有储量数据的金矿山信息发现, 西非已发现金矿储量全球占比超7%, 未来可能成为全球金矿开采与供应的重要一极。成因类型上以造山型金矿为主, 且成矿流体具有富水含碳为特征。砾岩型金矿次之, 独居特色, 其他类型矿床数量较少。西非金矿时间分布上具有广泛分布、高度集中的特点。古元古代埃布尼造山运动(2.2.~2.0 Ga)对金矿的形成具有绝对控制作用, 其他时期金矿数量相对较少。西非金矿空间分布广泛, 且具有明显的丛聚性分布特征, 集中分布于西非克拉通内的莱奥地盾区, 其他地区零星出露。根据西非金矿成矿地质背景与空间分布规律, 划分了23个Ⅳ成矿带。上述研究不仅有助于深入了解西非金矿成矿地质条件及矿床分布规律, 也对该区下步的找矿勘查部署具一定的指示意义, 更可能为该区金矿理论研究提供启示。     

A Climatological Perspective on Extratropical Synoptic-Scale Transient Eddy Activity Response to Western Pacific Tropical Cyclones

An observational study focusing on the contribution of tropical cyclones(TCs)that form over the western North Pacific(WNP)to the synoptic-scale transient eddy activity(STEA)over the North Pacific during the boreal autumn and early winter in the period 1979–2019 is presented in this paper.Statistical results show that WNP TCs entering the midlatitudinal North Pacific provide significant positive effects on the pentad mean strength of STEA,which is primarily concentrated over the Kuroshio/Oyashio Extensions(KOE)and regions from east of Japan to 160°W in the lower and midto-upper troposphere,respectively.TC intensity is highly indicative of the subsequent STEA with a correlation coefficient of 0.37/0.33/0.45 at 300 hPa/500 hPa/850 hPa exceeding the 99%confidence level for the period 1979–2019.The strength of STEA in the upper troposphere associated with TCs presents a more significant linear growth with TC intensity than that at the mid-to-lower levels after the cyclones enter the KOE region,suggesting that the impact of TCs on STEA gradually increases with height.Further analyses reveal that the contribution of TCs accounts for 4%–6%of the total STEA change over the KOE region during the late autumn and early winter.In addition,the influence of TCs on STEA experienced an interdecadal decrease from the early 2000 s through the early 2010 s.     

Changes in extended boreal summer tropical cyclogenesis associated with large-scale flow patterns over the western North Pacific in response to the global warming hiatus

Climate Dynamics - This study examines extended boreal summer (May–October) tropical cyclogenesis events (TCGEs) associated with large-scale flow patterns (LFPs) over the western North...