Relocation of the 10 March 2011 Yingjiang,China,earthquake sequence and its tectonic implications

An earthquake with Ms5.8 occurred on 10 March 2011 in Yingjiang county, western Yunnan, China. This earthquake caused 25 deaths and over 250 injuries. In order to better understand the seismotectonics in the region, we collected the arrival time data from the Yunnan seismic observational bulletins during 1 January to 25 March 2011, and precisely hand-picked the arrival times from high-quality seismograms that were recorded by the temporary seismic stations deployed by our Institute of Crustal Dynamics, China Earthquake Administration. Using these arrival times, we relocated all the earthquakes including the Yingjiang mainshock and its aftershocks using the double-difference relocation algorithm. Our results show that the relocated earthquakes dominantly occurred along the ENE direction and formed an upside-down bow-shaped structure in depth. It is also observed that after the Yingjiang mainshock, some aftershocks extended toward the SSE over about 10 km. These results may indicate that the Yingjiang mainshock ruptured a conjugate fault system consisting of the ENE trending Da Yingjiang fault and a SSE trending blind fault. Such structural features could contribute to severely seismic hazards during the moderate-size Yingjiang earthquake.

High-precision relocation of the aftershock sequence of the January 8,2022,M_(S)6.9 Menyuan earthquake

The 2022 Menyuan M_(S)6.9 earthquake,which occurred on January 8,is the most destructive earthquake to occur near the Lenglongling(LLL)fault since the 2016 Menyuan M_(S)6.4 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 71°-90°angle,whereas the east fault strikes 133°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.

How Efficient Is China＂s Industrial Relocation from East to West？ - Evidence from 20 Manufacturing Industries

With the acceleration of the rise of central China and the western development drive, industrial relocation from China＇s eastern region to the central and western regions is in full swing. However, does the relocation demonstrate industrial clustering effect？ Empirical studies based on twenty two-digit manufacturing industries in 27provinces from 2000 to 2009 demonstrate that industrial clustering effect appeared in central and western regions which had undertaken industrial relocation from eastern region; however, the studies do not show excessive administrative interference as evidenced by the significantly improved productivity of the relocated industries. Compared with non-labor- intensive manufacturing industries, labor-intensive manufacturing industries are easier to form cyclic accumulative effects. Studies also revealed that improvement in supporting infrastructure, industrial chain and higher labor quality in non-agriculture employment during urbanization are significant for central and western regions to undertake industrial relocation.

云南盐津地区两种地震序列的地震活动性分析

2020年9月—2021年1月,云南盐津地区出现了密集中小地震活动。为获取更完备的地震目录和更准确的震源参数,利用2020年1月—2021年2月云南及其邻区地震台网记录到地震事件的观测报告和连续波形,采用匹配定位方法检测到了1340次地震事件。利用联合波形互相关的双差地震定位方法进行重定位,获得了检测目录中351次地震的精确位置,对精定位后的地震活动时空分布特征进行分析研究,结果表明:盐津地区发生的密集中小地震活动为先后发生的2种不同类型的地震序列,沿两条不同走向和倾角的断裂分布,其中2020年9—10月的M_(L)3.9震群型地震序列发生在NNW走向、倾角约为75°的盐津—筠连断裂;2021年1月的M_(L)5.2孤立型地震序列发生在近SN走向、断层线与盐津—筠连断裂呈约30°夹角且倾角约为50°的隐伏断裂。

基于AHP-TOPSIS法的水库移民生计资本及生计稳定性研究

水库移民因征地搬迁而被迫重建生计系统,发掘移民生计资本优势,探究如何促进移民安置后的生计稳定和生计系统协调具有重要意义。以172项重大水利工程之一的广西LJ水利枢纽工程移民为例,以可持续生计框架为基础,考虑生计环境因素,采用AHP-TOPSIS法构建移民生计资本测度体系,使用收入多样性、自然资源依赖度及收入风险度衡量水库移民的生计稳定性,横纵向对比分析不同搬迁安置方式移民生计资本及生计稳定性变化,并根据耦合协调度修正模型研究其生计协调发展现状。研究结果表明:3种搬迁安置方式移民之间的6类生计资本增长存在显著差异,生计稳定性的变化也表现不同,由此影响了其生计协调发展状况。进城(集)镇安置移民得益于集镇商贸优势,将住房改造成商业门面以经营非农产业,有效利用经验优势和资本增量促进生计稳定,搬迁后的生计稳定性为三者最高,生计协调发展较好;集中居民点安置移民生计环境显著改善,自然资本降幅不大,人力资本较高,但尚未能充分利用,移民收入来源减少,生计稳定性下降,生计系统勉强协调;分散自主安置移民从业环境改善,人力资本增长率较高,移民自主发挥优势提高生计稳定性,生计系统接近初级协调发展。在本研究基础上,针对不同搬迁安置方式提出了促进移民生计可持续发展的建议。

易地扶贫搬迁户返贫风险因素识别及防范策略--基于武陵山区典型项目区的调查研究

巩固拓展脱贫攻坚成果,提升脱贫地区整体发展水平是“十四五”时期的重要任务。作为中国脱贫攻坚的“头号工程”和“标志性工程”,易地扶贫搬迁地区正处于巩固脱贫成果的脆弱性治理阶段。为剖析贫困户在易地搬迁后因各类因素诱发的返贫风险问题,本文以武陵山区四省市典型易地扶贫搬迁乡镇为研究区域,基于可持续发展理论和生计恢复力理论,构建涵盖“自然-社会-经济”三个层面的可衡量易地扶贫搬迁群众返贫风险因素的测评指标体系,运用Critic权重法、综合指数测算法和因子贡献度分析法,客观测算各级指标的权重及返贫风险得分,定量分析安置地区搬迁群众返贫风险程度及致贫因素。结果发现:第一,基于综合指数测算法,调研区域返贫风险程度分布呈现“中间大两头小”的橄榄型态势,表明重构发展环境后,仍存在不稳定因素导致返贫风险的客观存在。第二,基于因子贡献度分析法的计算结果,调研区域易地搬迁群众返贫风险因素的次序依次为:自然因素>经济因素>人力因素>保障因素>产业因素>家庭因素。基于此,提出加强教育培训、提高发展意识、完善社会保障、建立产业防线、强化金融支持和建立预警系统六点政策建议,以巩固脱贫攻坚成果,防范易地扶贫搬迁脱贫农户陷入返贫困境,解决搬迁后“稳得住”的问题,有效衔接乡村振兴。

Decadal Forecasts of Large Earthquakes along the Northern San Andreas Fault System, California: Increased Activity on Regional Creeping Faults Prior to Major and Great Events

The three largest earthquakes in northern California since 1849 were preceded by increased decadal activity for moderate-size shocks along surrounding nearby faults. Increased seismicity, double-difference precise locations of earthquakes since 1968, geodetic data and fault offsets for the 1906 great shock are used to re-examine the timing and locations of possible future large earthquakes. The physical mechanisms of regional faults like the Calaveras, Hayward and Sargent, which exhibit creep, differ from those of the northern San Andreas, which is currently locked and is not creeping. Much decadal forerunning activity occurred on creeping faults. Moderate-size earthquakes along those faults became more frequent as stresses in the region increased in the latter part of the cycle of stress restoration for major and great earthquakes along the San Andreas. They may be useful for decadal forecasts. Yearly to decadal forecasts, however, are based on only a few major to great events. Activity along closer faults like that in the two years prior to the 1989 Loma Prieta shock needs to be examined for possible yearly forerunning changes to large plate boundary earthquakes. Geodetic observations are needed to focus on identifying creeping faults close to the San Andreas. The distribution of moderate-size earthquakes increased significantly since 1990 along the Hayward fault but not adjacent to the San Andreas fault to the south of San Francisco compared to what took place in the decades prior to the three major historic earthquakes in the region. It is now clear from a re-examination of the 1989 mainshock that the increased level of moderate-size shocks in the one to two preceding decades occurred on nearby East Bay faults. Double-difference locations of small earthquakes provide structural information about faults in the region, especially their depths. The northern San Andreas fault is divided into several strongly coupled segments based on differences in seismicity.

高校实验室搬迁风险防控体系构建及评估

为了降低高校实验室搬迁因工作不当造成的经济损失和因不可抗力因素面临的安全风险,对高校实验室搬迁全过程进行风险点梳理,对各个风险点提出相应防控措施。基于环境影响评价理论和权重清单法构建高校实验室搬迁风险防控体系,得到实验室准许搬迁指数和实验室搬迁风险防控指数。以实验室准许搬迁指数评估实验室搬迁工作能否实施,以实验室搬迁风险防控指数评估实验室搬迁工作完成程度。该体系为实验室搬迁工作拟定了风险防范具体内容、工作方法和评估标准,提高了实验室搬迁风险防御能力,保障国有资产及人员安全。

政府搬迁对迁入地房价影响分析——以北京市政府搬迁为例

政府搬迁作为缓解“城市病”的常用政策,通过行政中心的迁移能改善资源配置格局,促进地区经济健康发展。本研究利用2016~2020年北京二手房交易数据,以时空结合的视角,在更小地理尺度上构造DID双重差分模型,分析北京市政府搬迁对迁入地房价的影响。研究结果表明:搬迁给迁入区住宅带来了涨幅约为2.9%的溢价效应,该效应也存在显著的时空异质性。此外,政府搬迁具有经济增长效应和公共资源再配置效应,且价值较低的住宅获益更显著。本研究在丰富房价影响机制的研究视角的同时,也为政府规划审核政府搬迁政策提供了理论参考,帮助其在地区经济发展过程中扮演好的“管理者”和“引导者”的角色。

城区油气管道迁改技术措施探讨与实践

随着国民经济的发展和城镇化进程的推进,部分城区的现有油气管道制约了城市规划和开发,需对油气管道进行迁改。详细论述了城区现有油气管道存在的问题、油气管道迁改技术与管理措施。重点对以下内容进行深入的阐述:第一,预留管道、减少土地占用和高后果区、设计时考虑管道的经济性、将无人机及遥感技术和GIS技术应用于管道勘察与监测等规划设计内容;第二,开展施工现场智能工地建设、重视居民意见和关切、重视环境保护等施工管理内容;第三,实施一体化管理模式、“一线工作法”等项目管理内容;第四,传感技术在管道运行监测中的应用、采用大数据与人工智能评估管道风险等运行维护内容;第五,管道迁改技术措施案例实践。

浅谈高速公路通信光缆的迁改实施及智能交通的信息化应用

近些年,随着我国经济的快速发展,高速公路的修建速度逐年递升,随着路网的加速布局,光缆的迁改割接愈发频繁,时间紧任务重的局面使得很多工程的迁改质量、施工工艺有所下降,从而影响其使用寿命。鉴于此,本文以高速公路沿线作为分析场景,分析通信光缆线路迁改的特点、原则及实施步骤,梳理迁改施工的技术现状与应用场景,期望能够为从事相关工程的技术人员提供一些技术参考与理论价值。

Accurate relocation of earthquakes in central-western China using the double-difference earthquake location algorithm

The double-difference earthquake relocation algorithm (DD algorithm) has been applied to the accurate relocation of 10057 earthquakes in the central-western China (21°-36°N, 98°-112E°) during the period of 1992-1999. In total, 79706 readings for P waves and 72169 readings for S waves were used in the relocation, and the source parameters of 6496 events were obtained. The relocation results revealed a more complete picture of the hypocentral distribution in the central-western China. In several seismic belts the relocated epicenters present a more defined lineation feature, reflecting the close correlation between the seismicity and the active tectonic structures. The relocated focal depths confirmed that most earthquakes (91 percent of the 6496 relocated events) in the central-western China were located at shallower depths not deeper than 20 km. The distribution of focal depths indicates that the seismogenic layer in the central-western China is located in the upper-mid crust with its thickness no deeper than 20 km.

Study on the computation method of temperature field of RCC dam

According to the construction characteristic of RCC dam cast by layers, three-dimensional finite element relocating mesh method is developed to simulate construction process and compute temperature field. The computation model of relocating mesh method is expatiated in detail; based on the thermodynamic properties of RCC materials, the feasibility and error of relocating mesh method are analyzed and demonstrated; The computation results in this article are verified by means of the temperature observation data of certain RCC gravity dam. The results show that the temperature field computed by three-dimensional finite element relocating mesh method can not only ensure the computation precision, but also improve the calculation efficiency greatly. This provides an effective method for simulating construction process and computing temperature field of RCC dam.

云南盐津地区中小地震活动性研究

1研究背景丰富的中小地震记录和准确的震源参数可以为研究地震活动性、发震断层及破裂特征、震情趋势判定、探索地震成核及触发机制等提供重要的地震学依据。Liu等(2019)利用模板匹配滤波和双差定位研究2016年青海门源M_(S)6.4地震的早期余震时空分布特征发现,冷龙岭北部断层破裂带中出现了16组重复地震群,可能是由主震震后滑移触发。李姣等(2020)对2017年漾濞M_(S)4.8和M_(S)5.1地震序列进行微震检测及重定位,确定了发震断层,并认为“震群(多震)型”相对于“主余型”地震序列,具有余震数量相对更少、余震活动衰减更快的特征。

倾斜煤层露天矿双破碎站布置及移设优化研究

为了确定出倾斜煤层纵采合理移设步距,以新疆准东露天矿为背景,揭示了倾斜煤层破碎站移设现状的不足之处,阐释了破碎站移设研究的改进方向,分析了单、双破碎站布置对露天矿开采的影响,通过破碎站移设步距费用相等法并加入卡车重载上、下坡的影响因素,构建出多台阶的纵采破碎站移设运费数学模型,确立了倾斜煤层纵采破碎站移设步距的通用公式,验证了通用公式的合理性,提出了端帮同侧分离布置、端帮两侧分台阶布置两种双破碎站端帮布置移设方案,并分析以上两种方案的优劣势选出端帮两侧分台阶布置为最优的布置移设方案,根据该最优的布置移设方案以准东露天矿的开采参数及参考其他露天矿的指标,计算出两破碎站在端帮纵采移设时合理的移设步距分别为481 m、492 m,验证双破碎站端帮台阶间移设时带式输送机布置的合理性。

基于自动快速密度峰值聚类的粒子群动态优化算法

针对常规多种群方法在求解动态优化问题时往往存在多样性缺失现象,提出一种基于自动快速密度峰值聚类的粒子群动态优化算法(DPCPSO)。首先,利用自动快速密度峰值聚类通过粒子的自身密度和相对距离创建无敏感参数子种群;然后,使用粒子群优化(PSO)来寻找最优解,在搜索过程中采用停滞计数器来判断粒子是否停滞,防止种群过早收敛;最后,采用最优粒子重定位策略响应环境变化。为了验证所提出算法的性能,在移动峰值基准(MPB)和广义动态基准生成器(GDBG)测试问题上进行了仿真实验。仿真实验中,所提算法性能与基于亲和传播聚类的动态优化算法(APCPSO)、基于聚类的动态优化(CPSO)算法等其他先进算法相比较,在峰值数大于20以及变化频率为2000和3000时均取得良好的结果。实验结果表明,所提算法更适合求解多模态和快变特性的动态优化问题。

川南威远地区中小地震震源机制解及应力场特征

基于四川省威远地区密集流动台站从2019年12月1日至2020年6月30日期间收集到的42个M_(L)3.0—4.5中小地震事件,采用Hypo2000定位法进行精定位,并利用HASH(Hardebeck&Shearer)法反演得到其中31次地震的震源机制解,之后利用阻尼区域应力反演方法计算了研究区的应力场参数。结果表明:中小地震主要分布在威远背斜南翼SSE向墨林场断层的两侧,震源深度集中在10 km以内,均为浅源地震;震源机制解类型以逆冲型为主,断层错动类型较为复杂,根据震源机制解结果,推测墨林场断层两侧存在一系列盲冲断层及正断型断层,同时研究区浅层地层中还可能存在其它小的隐伏断层或破裂;区域应力场为逆冲兼走滑型,其最大主应力轴σ1方位为103°,倾角为1°,最小主应力轴σ3方位为192°,倾角为51°,与震源机制解主要类型具有较好的一致性。

“南海挑战号”半潜式平台移井优化方法研究

为了解决半潜式平台移井方案计算困难的问题,本文以“南海挑战号”半潜式平台为依托,开展移井优化方法研究。依据多段悬链线控制方程,考虑平台和各井口的位置关系,建立了系泊链长度与顶张力的关系集。采用非支配排序遗传算法,给出了最佳移井路线方案。选取了4组现场移井方案进行对比分析,研究结果表明:所提出的计算方案有效地节约移井所需的时间成本和人力成本。以D_(3)-D_(2)移井操作为例,与现场采用方案相比,移井前后系泊链收放总量减少了40.17%,同时平台移井过程中的平稳程度降低了76.45%,大幅度的提高了移井作业平台的效率和安全性。

向东渠八尺门渡槽异地迁移保护施工技术

向东渠八尺门渡槽为大型线性连接的高耸水工构筑物,建于1973年,曾为解决东山岛淡水资源严重缺乏问题发挥了重要作用,为不可移动文物点。现因海洋生态环境治理,需拆除八尺门海堤,其上渡槽迁移至异地进行保护。针对渡槽的组成形式和结构特点,提出分体式移位法异地迁移方案。实践表明,采用钢套箱辅助吊装U型槽和托换装置辅助分段槽墩技术,能够有效保证异地迁移过程中渡槽文物本体安全,可为类似工程提供参考。

福田区实验学校箱涵迁改规划方案对比复核分析研究

随着城市规模的不断扩张,城市地下管网规模也迅速扩大,传统原有水工建筑物难以与当地城市的发展架构匹配,因此,地下管网的施工与改造工程项目大量涌现。以福田区实验学校箱涵改迁规划为研究背景,介绍了工程背景和水文条件,并对工程现状进行了分析,利用洪水分析法复核设计洪水洪峰流量,结合工程实际情况针对改造要点提出设计方案并进行验算,同时提出相应的质量管理控制措施。