2007年宁洱6.4级地震序列精定位

Five mobile digital seismic stations were set up by the Earthquake Administration of Yunnan Province near the epicenter of the main shock after the Ning’er M6.4 earthquake on June 3, 2007. In this paper, the aftershock sequence of the Ning’er M6.4 earthquake is relocated by using the double difference earthquake location method. The data is from the 5 mobile digital seismic stations and the permanent Simao seismic station. The results show that the length of the aftershock sequence is 40km and the width is 30km, concentrated obviously at the lateral displacement area between the Pu’er fault and the NNE-trending faults, with the majority occurring on the Pu’er fault around the main shock. The depths of aftershocks are from 2km to 12km, and the predominant distribution is in the depth of 8～10km. The mean depth is 7.9km. The seismic fault dips to the northwest revealed from the profile parallel to this aftershock sequence, which is identical to the dip of the secondary fault of the NE-trending Menglian-Mojiang fault in the earthquake area. There are more earthquakes concentrated in the northwest segment than in the southeast segment, which is perhaps related to the underground medium and faults. The depth profile of the earthquake sequence shows that the relocated earthquakes are mainly located near the Pu’er fault and the seismic faults dip to the southwest, consistent with the dip of the west branch of the Pu’er fault. In all, the fault strike revealed by earthquake relocations matches well with the strike in the focal mechanism solutions. The main shock is in the top of the aftershock sequence and the aftershocks are symmetrically distributed, showing that faulting was complete in both the NE and SW directions.     

汶川MS 8.0地震地表破裂带

2008年5月12日14时28分4秒,四川省汶川县发生MS8.0大地震。发震断裂为龙门山断裂带中的映秀-北川断裂。该次地震的地表破裂可分成2条,分别出现在龙门山断裂带中的映秀-北川断裂、彭县-灌县断裂上,前者破裂长度约200km,后者破裂长度约80km。本次地震的最大垂直和右旋水平同震位移出现在都江堰市虹口乡附近的映秀-北川断裂上,分别为(5±0.2)m和(4.8±0.2)m。破裂带南段出露的地表断层产状为N32°E/NW∠76°,其上的侧伏角为S75°～80°W,反映了该次地震在南段以逆冲运动为主,兼有少量的右旋走滑分量     

运用SDM方法研究2001年昆仑山口西MS8.1地震破裂分布:GPS和InSAR联合反演的结果

2001 年11月14日昆仑山口西M_S8.1地震是有现代仪器记录以来发生在青藏高原区域最大地震之一,对研究青藏高原的运动学模式具有重要意义.从地震发生至今,不同研究者运用不同资料和方法获取的地震破裂分布还存在一定差异.基于此,本文采用GPS和InSAR资料数据,参考最新研究成果,构建更为合理的断层几何模型,运用SDM方法反演本次地震的破裂分布.在反演中充分考虑不同数据权重的影响及InSAR数据中存在的整体偏移.结果显示本次地震断层性质以左旋走滑为主,最大破裂位错为~6.9 m,分布在35.76°N、93.40°E附近,地震较大破裂区域主要分布在地下20 km以内.同时,反演的位错分布在断层浅部与地质考察得到的地表破裂分布较为吻合.在与前人相关研究的对比中,显示本文结果的可靠性是较高的,例如,近地表破裂包络线与地表考察结果相近,地下破裂分布特征与前人提出的3次子地震事件相一致等,再一次佐证了此次地震由多次子地震事件组成的研究结论.     

Precise and Accurate In Situ Determination of Lead Isotope Ratios in NIST,USGS, MPI‐DING and CGSG Glass Reference Materials using Femtosecond Laser Ablation MC‐ICP‐MS

Lead isotope ratio data were obtained with good precision and accuracy using a 266 nm femtosecond laser ablation (fLA) system connected to a multi‐collector ICP‐MS (MC‐ICP‐MS) and through careful control of analytical procedures. The mass fractionation coefficient induced by 266 nm femtosecond laser ablation was approximately 28% lower than that by 193 nm excimer laser ablation (eLA) with helium carrier gas. The exponential law correction method for Tl normalisation with optimum adjusted Tl ratio was utilised to obtain Pb isotopic data with good precision and accuracy. The Pb isotopic ratios of the glass reference materials NIST SRM 610, 612, 614; USGS BHVO‐2G, BCR‐2G, GSD‐1G, BIR‐1G; and MPI‐DING GOR132‐G, KL2‐G, T1‐G, StHs60/80‐G, ATHO‐G and ML3B‐G were determined using fLA‐MC‐ICP‐MS. The measured Pb isotopic ratios were in good agreement with the reference or published values within 2s measurement uncertainties. We also present the first high‐precision Pb isotopic data for GSE‐1G, GSC‐1G, GSA‐1G and CGSG‐1, CGSG‐2, CGSG‐4 and CGSG‐5 glass reference materials obtained using the femtosecond laser ablation MC‐ICP‐MS analysis technique.     

2013年岷县—漳县MS6.6地震前水氡浓度的临界慢化现象研究

基于临界慢化理论, 以2013年7月22日甘肃岷县—漳县M_S6.6地震前南北构造带及邻区水氡浓度观测资料为例, 逐一计算了表征临界慢化现象的自相关系数和方差。 研究结果表明, 2013年岷县—漳县M_S6.6地震前, 10个台点水氡浓度资料表现出较明显的临界慢化现象, 且出现慢化现象的观测点空间分布具有一定丛集性, 慢化持续时间呈现出由南向北迁移的特征。 综合分析认为, 临界慢化方法可以有效识别水氡资料蕴含的慢化信息, 这些早期异常信号对判定前兆异常所处阶段以及深入理解前兆资料变化的物理内涵具有重要的科学意义。     

龙门山映秀-北川断裂带擂鼓探槽剖面古地震事件测年

2008年5月12日四川汶川发生MS8.0大地震,形成了200多km长的地震地表破裂带。破裂带的古地震研究对于认识龙门山断裂带的活动习性和大地震的发生规律具有重要的理论和现实意义。文中用光释光(OSL)测年中的校正感量简单多片再生法(SMAR),对映秀-北川地震地表破裂带擂鼓探槽样品进行了光释光测年,并对探槽中含有的炭屑进行了AMS14C测年。样品的光释光年龄和校正的AMS14C年龄吻合,该地区与汶川地震类似规模的上一次古地震事件发生在距今约(2.1±0.2)ka至(1.1±0.2)ka间     

利用Sentinel-2A多光谱成像仪与Landsat8陆地成像仪影像进行普陀山岛植被分类效果比较

卫星遥感技术可用于海岛资源调查。Sentinel-2A与Landsat 8两颗卫星都可免费提供空间分辨率较高的多光谱遥感影像,在海岛调查中的应用潜力较大。本文以浙江舟山普陀山岛为例开展了针对这两种影像在海岛植被分类中的应用效果的研究,分别利用Sentinel-2A多光谱成像仪（MSI）和Landsat 8陆地成像仪（OLI）影像基于最大似然法分类获得了该岛阔叶林、针阔混交林、针叶林、灌丛、草丛等植被及其他地物的分布情况,并进行了精度检验,结果表明MSI的总体分类精度略高于OLI。     

电感耦合等离子体质谱法同时测定地质样品中痕量碘溴硒砷的研究：Ⅱ.土壤及沉积物标准物质分析

样品用碳酸钠和氧化锌混合熔剂半熔，热水提取，然后用强酸性阳离子交换树脂将阴离子形式存在的分析元素与溶液中大量钠、锌等阳离子分离，采用电感耦合等离子体质谱法直接同时测定溶液中的碘、溴、硒、砷。用0.07mol/L的氨水溶液清洗进样系统，有效减少了碘等元素的记忆效应和清洗时间。方法检出限（10σ，DF=100）溴、碘分别为0.15和0.028μg/g，砷、硒分别为0.04和0.004μg/g。用土壤和沉积物等地质标准物质分析验证了方法的准确度和精密度，绝大多数分析结果在标准值的允许误差范围之内。样品10次测定的RSD为0.8%～2.8%。     

鄂尔多斯盆地东南缘上三叠统长8段砂岩储层 成岩作用与孔隙演化

鄂尔多斯盆地东南缘上三叠统延长组长8是该区油藏的主力储集层,主要为一套湖泊-三角洲相砂岩,储集岩主要为长石砂岩及长石岩屑砂岩.以岩心观察为基础,结合薄片鉴定、扫描电镜、压汞测试、X-衍射、包裹体测温、R.测定等方法认为,研究区延长组砂岩经历了压实、胶结、溶解、交代等成岩作用,成岩阶段已达中成岩阶段A期.成岩作用成为控制该区物性的一个关键因素,早期的机械压实和胶结作用使原生孔隙大量丧失,有机质分解形成的酸性流体使储集层中长石等易溶组分的溶蚀对储层物性起到重要的改善作用,成岩阶段后期以(含铁)碳酸盐胶结物为主的胶结又使砂岩致密化.成岩作用中的孔隙演化特征对鄂尔多斯盆地上三叠统延长组低渗透储集层的开发具有积极的意义.