中国大陆走滑断层段强震非均匀分布特性及其在工程地震中的应用

通过对中国大陆51条以走滑活动为主的断层段上强震分布的统计分析，得出强震沿活动断层段的分布是非均匀的，具有趋近段落中心的特点。并建立了强震沿活动断层段的非均匀分布模型，其概率分布密度p(K)与K的关系可以表述为p(K)=1．1206e^-3947K^2(K为宏观震中到断层段中心的距离与断层段半长度之比)。地震危险性分析结果表明，相对于均匀模型，采用非均匀模型导致了地震危险性分析结果有意义的变化，特别是对高震级档年发生率较高的潜在震源区及其附近地区的地震危险性分析结果有明显的影响。该非均匀模型的应用对地震爪小区划和重大工程场地地震安全性评价有一定的意义。     

用星载先进微波探测器（AMSU）资料开展区域地表洪涝分类监测

以微波辐射传输模式为基础，正演模拟分析星载先进微波探测器（AMSU）窗区通道微波亮温对地表洪涝信息的敏感性，结果表明中心频点分别为31.4、50.3和89.0 GHz的AMSU窗区通道2、3和15的微波亮温对地表洪涝特征敏感；以正演模拟计算结果为基础，选择对地表洪涝特征敏感的AMSU窗区通道为因子，组合形成AMSU洪涝指数AFI(AMSU Flooding Index)，进行地表洪涝区分类研究；地表洪涝分类结果与经机-地校验过的机载合成孔径雷达L-SAR资料分析结果进行对比分析，分类正确率可达73%。短时监测试验结果表明，应用美国第5代极轨业务环境卫星上装载的先进微波探测器（AMSU）微波资料可以在准全天候条件下，实现区域地表洪涝区分类实时监测，有效弥补红外和可见波段洪涝遥感探测技术在云天条件下无法实施的缺陷。     

分叉波痕在广西上泥盆统钙质浊积岩中的发现及意义

小型不对称分叉波痕(简称分叉波痕)发现于桂林杨堤剖面上泥盆统弗拉斯阶linguiformis牙形石带，桂林碳酸盐台地东南缘斜坡相钙质浊积岩鲍马序列C段。波长7．5～8．0cm，波高0．5～0．8cm，波痕指数15～10；向流面长5．0～7．0cm，背流面长2．5～4．0cm，波痕对称指数2．0～1．8；背流面向东倾；波脊较圆滑、缓曲，且具明显的分叉现象。是浊流流速减缓，密度流转化为牵引流后在低流态条件下，并叠加有推进型风暴浪作用形成的复合成因波痕。根据该波痕和寄主地层特征，推断含分叉波痕的阳朔碳酸盐盆地的最大水深约100m，极限水深小于200m。这一估计值应能代表广西乃至华南板块泥盆纪广泛发育的含牙形石动物群和钙质浊积岩碳酸盐沉积盆地的定量水深，可能也代表了弗拉斯阶一法门阶之交受集群绝灭事件重创的浅水海相生物与基本未受影响的深水海相生物的水深分界线。     

Stable isotope evidence for multiple fluid regimes during carbonate cementation of the Upper Tertiary Hazeva Formation, Dead Sea Graben, southern Israel

Stable carbon- and oxygen-isotope compositions of calcite and dolomite cements have been used to understand porewater evolution in the Upper Tertiary Hazeva Formation within the Dead Sea Graben, southern Israel. Sandstone samples were obtained from four boreholes in three tectonic blocks of the graben over depths of 253–6448 m, a variation that largely reflects differential subsidence of individual fault-bounded blocks. Early carbonate cements dominate diagenesis. Calcite occurs at <1600 m, but was replaced by dolomite at greater depths. Dolomite at 1600–2700 m is Fe-poor (<0.8 mol% FeCO₃), and at 4700–6200 m, Fe-rich (0.5–7.2 mol% FeCO₃). Magnesite, anhydrite and halite are the final diagenetic phases. Calcite has positively correlated δ¹⁸O (+21‰ to +25‰) and δ¹³C (−6‰ to −2‰) values that generally decrease with depth. Dolomite has a wider variation in δ¹⁸O (+18‰ to +30‰) and δ¹³C (−8‰ to −1‰) values, which also generally are lower with increasing depth. However, the δ¹³C and δ¹⁸O values of dolomite from the uppermost 400 m of the Hazeva Formation in the Sedom Deep-1 borehole are anomalous in spanning the entire range of stable carbon and oxygen isotopic compositions over this relatively small interval.The decreasing dolomite δ¹³C values likely indicate an increased contribution of carbon from organic sources with increasing depth. Except for the uppermost 400 m, Hazeva Formation dolomite in the Sedom Deep-1 borehole has stable carbon-isotope compositions that imply initial dolomitization at much shallower levels, prior to the preferential subsidence of this tectonic block. The oxygen isotopic compositions of the calcite cement are best explained by equilibration at present burial temperatures (≤55 °C) with porewater of meteoric origin. Its δ¹⁸O values increased from −5‰ at the shallowest depths to 0‰ at 1600 m. The dolomite oxygen isotopic compositions also reflect equilibration at present burial temperatures with porewaters ranging from 0‰ at 1600 m to +7‰ at 3600 m (100 °C). In the deepest fault block (Sedom Deep-1 borehole), however, increasingly Fe-rich dolomite has (re)equilibrated with porewater whose δ¹⁸O values decreased from +9‰ at 4750 m (120 °C) to +1‰ to +2‰ by 6200 m (150 °C).Much of the dolomite likely formed at relatively shallow depths from saline brines derived from precursors to the Dead Sea. These infiltrated the Hazeva Formation, mixing with and largely displacing meteoric water, and dolomitizing calcite. Rock–water ratios tended to be high during these processes. However, the upper 400 m of the Hazeva Formation in the deepest fault block were likely deposited during its rapid tectonic subsidence, and largely escaped the initial style of dolomitization pervasive elsewhere in the study area. These sediments were also capped by evaporites. This relatively thin interval likely became a preferential conduit for brines that escaped underlying and overlying strata, including the Fe-rich, lower ¹⁸O fluids (evolved seawater?) present in the deepest part of the graben. These rocks present the most promising target for the passage and accumulation of hydrocarbons in the study area.     

历史地震资料在核动力工程地震安全性评价中的应用

以三个核工程安全性评价为例,论述了运用历史地震及其资料对在核工程厂址近区域发生地震的确认及其对厂址的影响;区域范围内大震震中区的确认;对ＳＬ－２估计以及历史地震在ＳＬ－２确定的原则,历史地震资料在ＳＬ－２确定的不确定性中的应用。     

Earthquake probabilities and magnitude distribution ( M ≥6.7) along the Haiyuan fault, northwestern China

In recent years, some researchers have studied the paleoearthquake along the Haiyuan fault and revealed a lot of paleoearthquake events. All available information allows more reliable analysis of earthquake recurrence interval and earthquake rupture patterns along the Haiyuan fault. Based on this paleoseismological information, the recurrence probability and magnitude distribution for M≥6.7 earthquakes in future 100 years along the Haiyuan fault can be obtained through weighted computation by using Poisson and Brownian passage time models and considering different rupture patterns. The result shows that the recurrence probability of M _S≥6.7 earthquakes is about 0.035 in future 100 years along the Haiyuan fault. Foundation item: Joint Seismological Science Foundation of China (103034) and Major Research “Research on Assessment of Seismic Safety” from China Earthquake Administration during the tenth Five-year Plan.     

海原断裂带M6.7地震概率及其震级分布

海原断裂是中国西部的一条重要活动走滑断裂带，1920年沿该带发生的8.5级大震形成了长达230 km的地表破裂带和10 m的左旋走滑位移. 近10余年来，国内外学者对海原断裂开展了古地震研究，揭示出大量的古地震事件，为研究该断裂带上强震复发规律提供了重要的基础资料.本文利用这些古地震资料，采用泊松模型和布朗过程时间模型（Brownian passage time model），并考虑海原断裂带3个段落组合的不同尺度的破裂（单段破裂、双段破裂和全带破裂），经加权分析计算得到了海原断裂带未来百年强震（M6.7）复发的可能性及其震级分布. 计算结果表明，海原断裂带未来百年M6.7地震发生的可能性为0.035.      

Application of Brownian model in the northwestern Beijing, China

The mathematic theory of Brownian passage-time model and its difference from other recurrence models such as Poisson, lognormal, gamma and Weibull, were introduced. We assessed and analyzed the earthquake probabilities of the major faults with the elapsed time much greater than the recurrence interval in the northwest region of Beijing (China) in 100-year by using both Brownian passage-time model and Poisson model, and concluded that the calculated results obtained from Brownian passage-time model is more reasonable. Foundation item: Joint Seismological Science Foundation of China (103034) and Key Project “Assessment of Seismic Safety” from China Earthquake Administration during the tenth Five-year Plan.     

中国城市物流蔓延的时空演化特征——基于329个城市的物流用地面板数据

基于中国土地市场物流用地数据,构建用地蔓延指数模型,采用核密度、加权标准差椭圆等空间分析方法,从蔓延强度及方向等多维角度出发,获取2008—2017年中国城市物流蔓延的时空演化特征。研究发现：① 2008—2017年,中国城市物流蔓延强度最高为东北部,其次为东部、西部、中部,全国约67.48%的城市处于慢速蔓延状态。② 城市物流蔓延在全国范围内形成长三角、山东半岛和京津冀3个主要核密度高值区,物流用地冷点区主要分布在甘肃和云南等西部地区。③ 中国城市物流蔓延的空间分布重心轨迹经历了向东北?西南?东南方向的演化过程,一定程度上受国家战略和经济发展水平等因素的共同影响,应合理扩张物流用地,降低物流蔓延的负面影响。     

Major ion geochemistry and nutrient behaviour in the mixing zone of the Changjiang (Yangtze) River and its tributaries in the Three Gorges Reservoir

Inorganic ions and nutrients were measured at different depths of the Xiangxi and Daninghe Rivers to explore the mixing processes of representative bays in the Three Gorges Reservoir (TGR). HCO₃⁻ and Ca²⁺ are the dominant ions. Carbonate weathering is the most important mechanism controlling the ion water chemistry; however, important differences exist between the main channel and its tributaries. Major ion levels in the TGR bays depend on hydrological mixing. Results show that the major ions of Ca²⁺, Mg²⁺, Na⁺, K⁺, Sr²⁺, SO₄²⁻ and Cl⁻ show chemically conservative behaviour during transit through the bays of the TGR. This means the ions can be used as tracers in the same way that salinity is used in estuaries to explore behaviour of other non‐conservative elements and to indicate specific source waters. In contrast, nutrients are not conserved in the mixing zone. The mixing of the main channel and tributaries and biological utilization in backwater reaches were the key factor controlling nutrient distributions in Xiangxi and Daninghe Bays. Copyright © 2010 John Wiley & Sons, Ltd.