High-precision relocation of the aftershock sequence of the January 8, 2022, MS6.9 Menyuan earthquake

The 2022 Menyuan M_S6.9 earthquake, which occurred on January 8, is the most destructive earthquake to occur near the Lenglongling (LLL) fault since the 2016 Menyuan M_S6.4 earthquake. We relocated the mainshock and aftershocks with phase arrival time observations for three days after the mainshock from the Qinghai Seismic Network using the double-difference method. The total length and width of the aftershock sequence are approximately 32 km and 5 km, respectively, and the aftershocks are mainly concentrated at a depth of 7–12 km. The relocated sequence can be divided into 18 km west and 13 km east segments with a boundary approximately 5 km east of the mainshock, where aftershocks are sparse. The east and west fault structures revealed by aftershock locations differ significantly. The west fault strikes EW and inclines to the south at a 71º–90º angle, whereas the east fault strikes 133º and has a smaller dip angle. Elastic strain accumulates at conjunctions of faults with different slip rates where it is prone to large earthquakes. Based on surface traces of faults, the distribution of relocated earthquake sequence and surface ruptures, the mainshock was determined to have occurred at the conjunction of the Tuolaishan (TLS) fault and LLL fault, and the west and east segments of the aftershock sequence were on the TLS fault and LLL fault, respectively. Aftershocks migrate in the early and late stages of the earthquake sequence. In the first 1.5 h after the mainshock, aftershocks expand westward from the mainshock. In the late stage, seismicity on the northeast side of the east fault is higher than that in other regions. The migration rate of the west segment of the aftershock sequence is approximately 4.5 km/decade and the afterslip may exist in the source region.     

科技形变资料的管理模式

科学的进步使地形变监测事业得到长足发展，市场经济的繁荣催生出形变监测行业独有的管理之道。形变监测行业是个介于科研、IT及服务行业三者之间的特殊行业，因此，它的发展必须具有一定的科学性、前瞻性和服务性。     

破产企业的房地产有关法律问题的探讨

依法妥善处理破产企业房地产 ,是正确审理企业破产案件的关键。将破产企业无偿划拨取得的土地使用权进行拍卖 ,按规定交纳土地出让金后 ,余款列入破产财产用于清偿债务 ,是处理此类财产的最佳途径 ;安置职工和维护职工的权益 ,是在处理试点城市国有企业的土地和房产抵押权时的首要原则 ;破产企业福利性设施的科学界定 ,是妥善处理此类财产的关键     

中国土壤动物生态地理研究进展

This review summarizes main research findings in soil fauna eco-geography in China in the past 30 years.The subject areas and main results were overviewed including biodiversity and eco-geological distribution of soil fauna communities.Studies of ecological distributions of soil fauna and dynamic ranges in space from tropical,subtropical to temperate regions,and in categories from forest,grassland,desert,wetland,farmland to urban ecosystems,the responses and indications of soil fauna to soil environments.Ef...     

Erratum to: Purification and characterization of iron-cofactored superoxide dismutase from Enteromorpha linza

<正>Erratum to:Chinese Journal of Oceanology and Limnology Vol.31 No.6,P.1190-1195,2013http://dx.doi.org/10.1007/s00343-013-3049-3The supporting grant information on the footnote of the original version of this article needs to be altered and updated.The new information is given below.     

初论纳米比亚罗什皮纳地区斑岩型铜矿地质特征——以罗雷铜矿为例

纳米比亚罗什皮纳地区成矿地质条件优越,已发现罗雷铜矿、斯克皮铅锌矿、罗什皮纳铅铜矿及海伯超大型铜矿床以及多处Cu,Pb,Zn,Au及Bi等多处矿(化)点,可望形成铜、铅、锌、钼等多金属矿床集中区,找矿潜力巨大。该文在分析该区地质背景的基础上,总结了罗雷铜矿的地质特征,对其成因进行了探讨,并对罗雷铜矿和海伯铜矿之间的大部地区铜矿找矿潜力进行了展望,指出激发极化法是该区隐伏铜矿床勘查的有效物探手段。     

磁异常探测中磁场矢量导数快速计算方法

目的 针对计算磁位高阶导数常用的频率域快速傅立叶变换方法在实际应用中存在边界效应的问题,提出了分别在x和y方向上移相π/2二维余弦变换定义及其时域微分定理,推导出了磁场矢量分量的导数计算公式,并将其应用于方向解析信号的磁异常边界识别方法。通过棱柱体源磁场理论数据对比分析,验证了基于余弦变换计算磁位高阶导数的方法在不需要扩边或滤波处理、未增加额外处理数据和算法复杂度的前提下,可避免或减小边界效应,算法稳定性更好,计算结果精度更高。     

Effects of different operational modes on the flood‐induced turbidity current of a canyon‐shaped reservoir: case study on Liuxihe Reservoir,South China

Suspended matter is an important indicator of water quality in freshwater systems. The flood‐induced turbidity current plays a dominant role in the seasonal dynamic of suspended matter in the Liuxihe Reservoir (23°45′50″N; 113°46′52″E), a large, stratified reservoir at the Tropic of Cancer in southern China. Field measurements show that loading and distribution of suspended matter in the reservoir differ in typical wet, dry and medium years, as a result of different discharge volumes and water level variation patterns. Using historical data and the practical demand for water supply and flood control, we generalized two feasible reservoir operational modes: flood impounding mode (drawing down the reservoir to a low level before flood events to impound inflow during the flooding season) and moderate level change mode (drawing down the reservoir to a moderate level before flood events, then keeping the level within the flood control level during runoff events). To examine the effects of different operational modes and outlet depths on the reservoir's flood‐induced turbidity current, a numerical simulation model was applied in three types of hydrological conditions. The results show that the mode with moderate drawdown and recharge processes can decrease loading of suspended matter in spring and promote turbidity current release during flood events, and upper withdrawal can improve the effects of turbid water release. We suggest that more attention should be focused on water quality management in the reservoir operation stage, severe artificial water level fluctuation being avoided and selective withdrawal becoming an optional management measure. Copyright © 2012 John Wiley & Sons, Ltd.     

纳米碳酸钙材料的工业合成与应用

该文对目前工业上生产纳米碳酸钙的方法作了较为详细的综述。对一步碳化法、两步碳化法、多段喷雾碳化法、旋转填充床碳化反应器碳化技术制备链形、纺锤形、球形、立方形等不同形状的纳米碳酸钙材料的方法进行了比较和总结     

新疆天池景区生态安全度时空分异特征与驱动机制

本研究基于2000、2010年新疆天池风景名胜区的TM遥感影像、2000-2010年新疆统计年鉴、野外实地调查等数据,构建研究区的景观生态安全度,采用ESDA、半变异函数空间分析、逐步回归等方法,分析各样点景观生态安全度的时空演变特征,探讨导致格局演变的驱动机制。结果表明:① 2000-2010年,高景观生态安全度范围由南向北转移;中景观生态安全度区域由南北向中部集中;低景观生态安全度呈现由南向北扩散的趋势。② 景观生态安全度全局空间自相关较显著,随时间演变,空间集聚水平降低;局域空间自相关呈现集群分布向随机分布转变的趋势。③ 变程范围内,景观生态安全度值的各向异性与弱空间相关性特点是结构性因素和随机性因素综合作用的结果。④ 经度、纬度、海拔因子对景观生态安全度的影响显著;放牧、旅游以及政策活动影响景观生态安全度中小尺度格局,对景观生态安全度的演变有重要影响。