Formation mechanism of fault accommodation zones under combined stress in graben basin:Implications from geomechanical modeling

A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation areas.This study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical modeling.Using three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation zones.Combined with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben basin.Integrating the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were summarized.Influenced by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale faults.During the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly developed.The junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation zones.During the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were furtherly inherited and developed.This stage was the molded and formative period of the FAZ,the low-order faults,and the depression in the DXFZ.

Observing eddy dye patches induced by shear instabilities in the surf zone on a plane beach

The effects of surf zone eddy generated by alongshore currents on the deformation and transport of dye are still poorly understood,and related tracer release experiments are lacking.Therefore,a tracer release laboratory experiment was conducted under monochromatic,unidirectional incident waves with a large incident angle(30°)on a plane beach with a 1:100 slope in a large wave basin.A charge-coupled device suspended above the basin recorded the dye patch image.The evolution of eddy dye patch was observed and the transport and diffusion were analyzed based on the collected images.Subsequently,a linear instability numerical model was adopted to calculate the perturbation velocity field at the initial stage.The observation and image processing results show that surf zone eddy patches occurred and were separated from the original dye patches.Our numerical analysis results demonstrate that the structure of the perturbation velocity field is consistent with the experimental observations,and that the ejection of eddy patches shoreward or offshore may be ascribed to the double vortex.

Strategies for Construction of Sustainable Development Experimental Zone in Fumian District,Yulin City

From strengthening the construction of an innovation system,adhering to the green development model of the industry,advancing the rural revitalization strategy,strengthening the protection and inheritance of cultural heritage,accelerating the development of social undertakings,and expanding the space for regional cooperation,this paper discusses the strategies for the construction of sustainable development experimental zone in Fumian District,Yulin City.It is intended to build Fumian District into a vibrant,economically prosperous,urban and rural integrated,characteristic cultural,safe and harmonious,inclusive and open district.

Upper Limit for Rheological Strength of Crust in Continental Subduction Zone:Constraints Imposed by Laboratory Experiments

The transitional pressure of quartz coesite under the differential stress and highly strained conditions is far from the pressure of the stable field under the static pressure. Therefore, the effect of the differential stress should be considered when the depth of petrogenesis is estimated about ultrahigh pressure metamorphic (UHPM) rocks. The rheological strength of typical ultrahigh pressure rocks in continental subduction zone was derived from the results of the laboratory experiments. The results indicate the following three points. (1) The rheological strength of gabbro, similar to that of eclogite, is smaller than that of clinopyroxenite on the same condition. (2) The calculated strength of rocks (gabbro, eclogite and clinopyroxenite) related to UHPM decreases by nearly one order of magnitude with the temperature rising by 100 ℃ in the range between 600 and 900 ℃. The calculated strength is far greater than the faulting strength of rocks at 600 ℃, and is in several hundred to more than one thousand mega pascals at 700-800 ℃, which suggests that those rocks are located in the brittle deformation region at 600 ℃, but are in the semi brittle to plastic deformation region at 700-800 ℃. Obviously, the 700 ℃ is a brittle plastic transition boundary. (3) The calculated rheological strength in the localized deformation zone on a higher strain rate condition (1.6×10 -12 s -l ) is 2-5 times more than that in the distributed deformation zone on a lower strain rate condition (1.6×10 -14 s -1 ). The average rheological stress (1 600 MPa) at the strain rate of 10 -12 s -1 stands for the ultimate differential stress of UHPM rocks in the semi brittle flow field, and the average rheological stress (550-950 MPa) at the strain rate of l0 -14 - 10 -13 s -l stands for the ultimate differential stress of UHPM rocks in the plastic flow field, suggesting that the depth for the formation of UHPM rocks is more than 20-60 km below the depth estimated under static pressure condition due to the effect of the differential stress.

Spatial-temporal characterization of the San Andreas Fault by fault-zone trapped waves at seismic experiment site,Parkfield,California

In this article,we review our previous research for spatial and temporal characterizations of the San Andreas Fault(SAF)at Parkfield,using the fault-zone trapped wave(FZTW)since the middle 1980s.Parkfield,California has been taken as a scientific seismic experimental site in the USA since the 1970s,and the SAF is the target fault to investigate earthquake physics and forecasting.More than ten types of field experiments(including seismic,geophysical,geochemical,geodetic and so on)have been carried out at this experimental site since then.In the fall of 2003,a pair of scientific wells were drilled at the San Andreas Fault Observatory at Depth(SAFOD)site;the main-hole(MH)passed a~200-m-wide low-velocity zone(LVZ)with highly fractured rocks of the SAF at a depth of~3.2 km below the wellhead on the ground level(Hickman et al.,2005;Zoback,2007;Lockner et al.,2011).Borehole seismographs were installed in the SAFOD MH in 2004,which were located within the LVZ of the fault at~3-km depth to probe the internal structure and physical properties of the SAF.On September 282004,a M6 earthquake occurred~15 km southeast of the town of Parkfield.The data recorded in the field experiments before and after the 2004 M6 earthquake provided a unique opportunity to monitor the co-mainshock damage and post-seismic heal of the SAF associated with this strong earthquake.This retrospective review of the results from a sequence of our previous experiments at the Parkfield SAF,California,will be valuable for other researchers who are carrying out seismic experiments at the active faults to develop the community seismic wave velocity models,the fault models and the earthquake forecasting models in global seismogenic regions.

Phase relations,Structure and Thermodynamic Properties of Na-Majorite:Experimental and Computer Modeling

Na-majorite is observed as an inclusion in mantle-derived diamonds and as mineral of rare ultra-deep xenoliths in kimberlites.Our experiments in different alumosilicate and carbonate-silicate systems at 7.0 and 8.5 GPa suggest that Na is incorporated in pyrope-rich garnet via the coupled substitution like Mg+Al=Si+Na.Thus,the mechanism of the Na-majorite formation assumed on mineralo-

THE CHARACTERISTICS AND MODELLING EXPERIMENTS ON THE DEPOSIT-CONTROLLING STRUCTURE OF SHEAR-ZONE GOLD DEPOSIT IN CHINA

THE CHARACTERISTICS ANDMODELLING EXPERIMENTS ON THEDEPOSIT-CONTROLLING STRUCTUREOF SHEAR-ZONE GOLD DEPOSITIN CHINAWu Xueyi(Institute of Geochemistry, Academia Sinica, Guiyang, 550002, China)shear zone, gold-controlled structure, modelling experimentThe shear-zone gold deposits found in China can be divided into four types: (1) gold deposits controlled by the ductile shear-zones; (2) gold deposits controlled by the brittle-ductile shear zones; (3) gold deposits conntrolled by the ductile-brittle shear zones; (4) gold deposits controlled by the brittle shear zones. These gold deposits mostly occurred in the regions with higher abundance of gold, which underwent a long and complicated evolution-ary process and had obvious zoning and multiperiod metallogenic feature. The modelling exper-imental result of gold-controlled structure shows that the thermodynamics of compresso-shear structures made gold mobilizing and migrating in the earlier stage of shear zone; and that the extension process did

数字经济对环境污染的影响及作用机制研究

环境污染是人类面临的重要威胁之一,数字经济有望成为抑制环境污染的新抓手。基于大数据试验区准自然实验,选取中国278个地级市2012—2021年面板数据,采用双重差分模型分析数字经济对环境污染的影响及作用机制。研究发现,数字经济能够显著抑制城市环境污染。该结论经过平行趋势检验、PSM-DID检验、安慰剂检验及排除同期相关政策影响后依然成立。作用机制检验发现,数字经济可通过加强环境规制和提升实质性技术创新两条传导路径抑制环境污染,而策略性技术创新传导路径未获数据支持。异质性分析表明,与基础设施统筹发展试验区相比,跨区域试验区和区域示范试验区所体现的数字经济环境污染抑制效应更强;沿海城市以及数字普惠金融水平较高的城市数字经济对环境污染的抑制效应更强。

基于CA-Markov模型的云南自由贸易试验区土地利用和景观格局时空演变分析及模拟预测

为探究云南自由贸易实验区土地利用和景观格局变化特征,协调经济发展和生态保护,促进土地资源高效可持续利用。本文通过Arc GIS 10.6、Fragstats 4.0、IDRISI 17.0以自贸区2010、2015、2020年三期遥感影像为数据源,研究分析其土地利用变化和景观格局时空演变特征,并利用CA-Markov模型,模拟预测2025年土地利用类型和景观格局。研究表明,(1)三个片区土地利用结构变化为建设用地增加,林地、耕地和未利用地减少,草地和水体基本保持不变。(2)在研究期前期,建设用地主要来源于林地和耕地,后期为未利用地,并加大对生态环境的保护力度。(3)在发展过程中,其整体景观破碎度逐渐降低,但连通性和集聚度逐渐加强,生物多样性减少;耕地、林地破碎化程度加重,聚集度和景观优势不断下降,并转换为建设用地;随着人类干扰因素不断增强,建设用地优势表现明显,聚集度高,区域景观自我调节能力增强,景观空间结构更加稳定。

高温高压实验揭示俯冲带蛇纹岩熔融行为与高镁岩浆成因

近年来一些研究在岛弧岩浆中发现了蛇纹岩组分,这表明俯冲至弧下的蛇纹岩不仅为地幔楔提供流体,而且可以通过部分熔融参与岛弧岩浆形成。然而,蛇纹岩在地幔楔中的熔融行为及其在俯冲带物质循环中的作用仍未进行深入研究。因此,本研究选择3种蛇纹岩样品:蚀变原岩分别为二辉橄榄岩(SE2)和方辉橄榄岩(SE3)的天然蛇纹岩,以及模拟含有大量滑石的合成蛇纹岩样品(SEQ),在700~1300℃和4 GPa的温度压力条件下进行了模拟实验,限定了蛇纹岩的熔融温度,分析了实验产生的熔体成分。研究发现,不同类型蛇纹岩的固相线存在显著差异,SE3、SEQ和SE2蛇纹岩的固相线分别为900~960℃、960~1100℃以及1150~1200℃。这3种蛇纹岩的固相线均高于俯冲板片上表面的温度,要求蛇纹岩通过底辟作用进入地幔楔以发生部分熔融。根据实验结果,本研究认为SE2和SEQ蛇纹岩可以在地幔楔底部相对较低的温度条件下(960~1100℃)即发生熔融,产生科马提质岩浆;而在上覆地幔楔更高温度条件下(>1200℃),SE2蛇纹岩可以发生更广泛、更高程度的部分熔融,产生玻安质岩浆。

从动物防疫角度浅谈实验动物运输的法律规定

实验动物运输活动应按照相关法律规定做好动物防疫工作,以防止实验动物疫病远距离跨地区传播。本文从动物防疫的角度概括了国内机构通过道路运输实验动物,尤其是向无规定动物疫病区运输实验动物,在运输前、中、后不同环节应遵循的法律规定及相关要求,并指出运输环节易出现的违规问题及处罚规定,提出了动物防疫部门应加强运输实验动物的动物卫生监管及相关法律法规宣传,实验动物运输机构应加强动物防疫相关法规的学习,做到依法运输实验动物。本文为相关单位及人员做好实验动物卫生防疫工作提供参考。

A method for extracting the preseismic gravity anomalies over the Tibetan Plateau based on the maximum shear strain using GRACE data

The occurrence of earthquakes is closely related to the crustal geotectonic movement and the migration of mass,which consequently cause changes in gravity.The Gravity Recovery And Climate Experiment(GRACE)satellite data can be used to detect gravity changes associated with large earthquakes.However,previous GRACE satellite-based seismic gravity-change studies have focused more on coseismic gravity changes than on preseismic gravity changes.Moreover,the noise of the north–south stripe in GRACE data is difficult to eliminate,thereby resulting in the loss of some gravity information related to tectonic activities.To explore the preseismic gravity anomalies in a more refined way,we first propose a method of characterizing gravity variation based on the maximum shear strain of gravity,inspired by the concept of crustal strain.The offset index method is then adopted to describe the gravity anomalies,and the spatial and temporal characteristics of gravity anomalies before earthquakes are analyzed at the scales of the fault zone and plate,respectively.In this work,experiments are carried out on the Tibetan Plateau and its surrounding areas,and the following findings are obtained:First,from the observation scale of the fault zone,we detect the occurrence of large-area gravity anomalies near the epicenter,oftentimes about half a year before an earthquake,and these anomalies were distributed along the fault zone.Second,from the observation scale of the plate,we find that when an earthquake occurred on the Tibetan Plateau,a large number of gravity anomalies also occurred at the boundary of the Tibetan Plateau and the Indian Plate.Moreover,the aforementioned experiments confirm that the proposed method can successfully capture the preseismic gravity anomalies of large earthquakes with a magnitude of less than 8,which suggests a new idea for the application of gravity satellite data to earthquake research.

穿越不良地质带隧道结构响应规律模型实验平台设计

为研究隧道穿越不良地质带的结构响应特性,以福宜高速公路阳宗隧道工程为依托,设计了穿越不良地质带隧道结构响应规律模型实验平台,实现了几种不同类型不良地质带工况下隧道工程缩尺模拟实验。基于该平台,详细介绍了所有系统的结构及功能,针对4种不良地质带工况制定了相应实验方案,并以断层破碎带作为典型不良地质案例,演示了模型实验全过程,分析了隧道穿越断层破碎带区域的结构响应规律,最后将实验结果与数值模拟结果进行对比,验证了模型实验的有效性。

福州市滨海新城与平潭综合实验区联动发展规划探析

以福州市滨海新城与平潭综合实验区为研究对象,剖析其各自发展特征,指出滨海新城与平潭综合实验区联动发展的必要性及重要性,系统搭建包括空间统筹、产业互联、设施一体、政策共享的联动发展思路框架,提出共建宜居生活圈、分工协作培育产业优势、强化服务设施共建共享、构建共担共享机制等方面的联动发展策略,探索联动发展的新模式与新路径。

大数据战略对制造业高质量发展的影响研究

文章以国家级大数据综合试验区的设立作为准自然试验,考察大数据战略对制造业高质量发展的影响、作用机制以及空间效应。研究发现:国家级大数据综合试验区建设整体上促进了制造业高质量发展,且对邻近地区的制造业高质量发展具有空间溢出效应;试验区建设通过改善资本要素错配促进制造业高质量发展,而劳动力要素错配的中介作用不显著;产业结构升级增强了试验区建设推动制造业高质量发展的正向促进作用;在技术创新、互联网和人力资本发展水平高的地区试验区建设对区域内制造业高质量发展的积极作用更明显。

国家级大数据综合试验区与新质生产力——基于230个城市的经验证据

社会形态更替本质上是生产力从低质到高质的发展过程,生产力水平提升是人类社会发展的根本动力。新质生产力以“新”为起点,以“质”为重点,以“生产力”为落脚点,培育新质生产力着力点在新科技、新产业和新要素。数据要素作为数字时代战略性生产要素,是实现企业数字化、智能化的关键。国家级大数据综合试验区深耕数据蓝海,培育大数据产业,释放强劲生产力效能。探究大数据试验区依托数据要素助力现代化经济体系建设的现实路径,对加快形成新质生产力,利用科技创新实现经济高质量增长,推进中国式现代化建设具有重要意义。文章梳理现有新质生产力的概念与内涵,引入数据要素,理清大数据综合试验区赋能新质生产力理论机制,基于2011—2021年全国230个地级市面板数据,以科技生产力、绿色生产力和数字生产力三维度构建城市层面新质生产力指标体系,将国家级大数据综合试验区试点政策视为准自然实验,构建多期双重差分模型实证检验试点政策效应,并从多维度刻画试点政策效应异质性。研究结果发现:国家级大数据综合试验区显著赋能新质生产力提升,且这一结论在多种稳健性检验下仍然成立。维度异质性分析表明,试点政策在科技生产力、绿色生产力和数字生产力三个维度均存在显著赋能;地域异质性分析表明,在东部沿海地区和长江经济带地区政策赋能效应更为明显;经济特征异质性分析表明,拥有较高水平产业结构、人力资本和数字基础设施的城市政策赋能作用突出。机制分析表明,试点政策激励企业加大研发投入进而赋能新质生产力。据此提出政策建议:依据新质生产力子维度优化试点政策驱动数据要素渠道;针对地区产业结构异质性,有的放矢推进大数据综合试验区改革;政策实施环节充分发挥地方政府引导和企业模范带头作用。

川中古隆起北斜坡岩溶储层岩电分析及气层识别

四川盆地川中古隆起北斜坡震旦系是受岩溶控制的巨厚白云岩油气藏,气水关系十分复杂,储层呈基质孔隙度低、次生溶蚀孔洞发育特征,而且储层类型多样,致使储层岩电关系存在非Archie现象,同时储层的非均质性和地层水矿化度的差异掩盖了气水的测井响应特征,造成测井气水识别难度大。为此,通过对不同类型全直径岩电参数、声学特性实验数据和地层水资料的综合分析,优选了饱和度模型参数,建立了含水饱和度计算电阻率—实测电阻率重叠判别法、基质电阻率—实测电阻率重叠判别法、理论计算纵横波速度比—实测纵横波速度比重叠判别法3种以声波、电阻率相结合的测井气层识别方案。应用该技术对川中古隆起北斜坡震旦系灯影组储层进行解释,符合率达到93.1%。

绿色金融改革创新促进企业绿色全要素生产率增长了吗?--来自工业上市公司的绿色转型证据

经济绿色转型是实现“双碳”目标的必由之路,企业的绿色转型发展是经济实现绿色转型的关键环节。本文以2012—2019年中国沪深A股工业上市公司为研究对象,使用企业绿色全要素生产率作为企业绿色转型的评价指标,以2017年绿色金融改革创新试验区的设立为准自然实验,分析研究绿色金融改革创新对企业绿色转型发展的影响。结果表明,绿色金融改革创新能够显著促进试验区内企业绿色全要素生产率增长率的提升,进而促进企业绿色转型。进一步分析得出,试验区内企业融资约束的缓解和政府政策支持对企业绿色转型有所促进,但其对国有企业和重污染企业的影响却未达预期。本文为绿色金融改革创新的政策效应评估和企业绿色转型发展提供了理论层面的支持和直接经验证据,为各地区制定绿色金融政策提供了参考。

STRENGTH ANALYSIS OF CLAMPING IN MICRO/NANO SCALE EXPERIMENTS

Two kinds of clamping in micro/nano scale experiments are investigated in this paper, one based on electron-beam-induced deposition, and the other on the van der Waals interaction. The clamping strength and mechanism are analyzed both theoretically and experimentally. The influence of relative humidity on the micro/nano clamping and the method of electrostatic clamping are discussed. The clamping strength and performance of different clamping methods are compared considering the size and material of the clamped objects, and the application environments.