Discussion on origin of Pn velocity variationin China and adjacent region

Pn velocity lateral variation and anisotropy images were reconstructed by adding about 50 000 travel times from the regional seismic networks to the datum set of near 40 000 travel times from National Seismic Network of China used by WANG, et al. We discussed the relation of Pn velocity variation to Moho depth, Earths heat flow, distribution of Cenozoic volcanic rock and the result of rock experiment under high pressure and high temperature. The result of quantitative analysis indicates that Pn velocity is positively correlated with the crust thickness and negatively correlated with the Earths heat flow. Two linear regression equations, one between Pn velocity and crust thickness, and the other between Pn velocity and heat flow, were obtained. The rate of variation of Pn veloc-ity vP with pressure P, Pv/p, estimated from the velocity variation with crust thickness Hv/p, is close to the result obtained from the rock experiment under high pressure and high temperature. If the effect of crust thick-ness on Pn velocity is deducted from the velocity variation, then the low Pn velocity beneath Qinghai-Xizang pla-teau is more notable. The low Pn velocity regions well agree with the Cenozoic volcanic rock. In the several re-gions with significant anisotropy, the direction of fast Pn velocity is consistent with the orientation of maximum principal crustal compressive stress, and also with the direction of present-day crustal movement. It indicates that the fast Pn velocity direction may be related to the deformation or flow of top mantle material along the direction of maximum pressure.

Three dimensional shear wave velocity structure of crust and upper mantle in South China Sea and its adjacent regions by surface waveform inversion

We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). It partitions the large-scale optimization problem into a number of independent small-scale problems. We adopted surface waveform inversion with an equal block (2((2() discretization in order to acquire the images of shear velocity structure at different depths (from surface to 430 km) in the crust and upper-mantle. The resolution of all these anomalies has been established with (check-board( resolution tests. These results show significant difference in velocity, lithosphere and asthenosphere structure between South China Sea and its adjacent regions.

Crustal Motion Characteristics in the Eastern Margin of the Tibetan Plateau and Adjacent Regions after the Wenchuan Earthquake

The Wenchuan earthquake has altered the crustal motion characteristics in the eastern margin of the Tibetan Plateau and adjacent regions.Using discontinuous GPS survey data for 2008–2012, the velocity field for the Eurasia reference framework has been obtained, and the general trend of contemporary crustal motion after the occurrence of the Wenchuan earthquake has been studied.In addition, using the velocity field, the block movement velocity has been estimated by least-squares fitting.Furthermore, the properties and displacement rates of main faults have been obtained from the differences in velocity vectors of the blocks on both sides of the faults.The results reveal that there are no obvious changes in the general characteristics of crustal motion in this area after the Wenchuan earthquake.The earthquake mainly changed the rate of the movement of the Chuan-Qing block and caused variation in the movement direction of the South China block.The effect of the earthquake on faults is mainly reflected in variations in fault displacement velocity; there is no fundamental change in the properties of fault activity.The displacement rates of the Xianshuihe fault decreased by 3–4 mm/a, the Longmenshan fault increased by 9–10 mm/a, and the northern segment of the Anninghe fault increased by approximately 9 mm/a.Furthermore, the displacement rates of the Minjiang, Xueshan, Huya, Longquanshan, and Xinjin faults increased by 2–3 mm/a.This implies that the effects of the Wenchuan earthquake on crustal movement can mainly be observed in the Chuan-Qing, South China, and N-Chuan-Dian blocks and their internal faults, as well as the Xianshuihe and Longmenshan faults and the northern section of the Anninghe fault.The reason for this is that the Wenchuan earthquake disturbed the kinematic and dynamic balance in the region.

Late Carboniferous-Early Permian Volcanic Event Deposits and Stratigraphic Correlation in Shandong Province and Its Adjacent Regions

Deposits of 10 volcanic events of 6 stages have been discovered by the authors after detailed field and lab studies of the Benxi and Taiyuan Formations in Shandong Province and its adjacent regions. They show certain temporal-spatial distribution characteristics. Volcanic fragments were probably derived from two different volcanic sources north and south of the North China Platform, while the magma of the two volcanic sources was probably derived from the lower crust. A new stratigraphic correlation scheme is put forward for the Benxi and Taiyuan Formations in this region on the basis of previous biostratigraphic work with the regionally widespread volcanic event layers as the marker bed for the isochronous stratigraphic correlation on a super-regional scale and in conjunction with the maximum transgressive event layers.

Study on Ground Motion Attenuation Relation in Shanghai and Its Adjacent Region

Based on intensity data in Shanghai and its adjacent region, the intensity attenuation relation is determined. Selecting the western United States as a reference area where there are rich strong ground motion records and intensity data, and by determining ground motion attenuation relation in an area lacking in strong ground motion data, we obtain the ground motion attenuation relation in Shanghai and its adjacent region.

Discussion on origin of Pn velocity variation in China and adjacent region

Pn velocity lateral variation and anisotropy images were reconstructed by adding about 50 000 travel times from the regional seismic networks to the datum set of near 40 000 travel times from National Seismic Network of China used by WANG, et al. We discussed the relation of Pn velocity variation to Moho depth, Earths heat flow, distribution of Cenozoic volcanic rock and the result of rock experiment under high pressure and high temperature. The result of quantitative analysis indicates that Pn velocity is positively correlated with the crust thickness and negatively correlated with the Earths heat flow. Two linear regression equations, one between Pn velocity and crust thickness, and the other between Pn velocity and heat flow, were obtained. The rate of variation of Pn veloc-ity vP with pressure P, Pv/p, estimated from the velocity variation with crust thickness Hv/p, is close to the result obtained from the rock experiment under high pressure and high temperature. If the effect of crust thick-ness on Pn velocity is deducted from the velocity variation, then the low Pn velocity beneath Qinghai-Xizang pla-teau is more notable. The low Pn velocity regions well agree with the Cenozoic volcanic rock. In the several re-gions with significant anisotropy, the direction of fast Pn velocity is consistent with the orientation of maximum principal crustal compressive stress, and also with the direction of present-day crustal movement. It indicates that the fast Pn velocity direction may be related to the deformation or flow of top mantle material along the direction of maximum pressure.

Lg coda Q_0 value and its relation with the tectonics in Chinese mainland and adjacent regions

We have collected 432 vertical component records from 45 stations of new CENC （China Earthquake Network Center） in Chinese mainland and adjacent regions. These records were used to calculate Q0 （Q at 1Hz） and η values of Lg coda from each station by the stack spectral ratio （SSR） method. Then the tomography method was applied to obtaining lateral variation of Q0 and η values in Chinese mainland and adjacent regions. The result indicates that Q0 value varies between 150 and 600 in the studied areas. Yunnan, southwest Sichuan, and northwest Myanmar show the lowest Q0 value （Q0〈240） and the crust of these regions is characterized by complicated crack and strong hydrothermal activity. The highest Q0 value （Qo〉510） exists in the border of southern Mongolia, Alxa and Ordos block. The η value varies between 0.45 and 0.75 in Chinese mainland and its adjacent regions.

Horizontal movement and strain characteristics in Tianshan and its adjacent region with GPS deformation data

Based on the multiple-term horizontal velocity solutions of 230 GPS monitoring sites in Tianshan and its adjacent region, the GPS site velocity fields and crustal horizontal strain fields in the area have been obtained. The results show that the crustal shortening rate of Tianshan, with the longitude （77°±1°）E as the boundary, gradually decreased towards two sides, from the south to the north, indicating that the pushing force of plate becomes weaker along with the fold deformation decreasing of the Tianshan. The direction of principal compressive strain of Tianshan and its adjacent area, nearly NNW, is basically perpendicular to the Tianshan cordillera trend, suggesting the distribution and variation of maximum principal compressive stress in Tianshan and its adjacent region resulted from collision and extrusion of Indian Plate. This paper indicates that the maximum shear strain field mainly con- centrates on two areas, one is Isyk lake of North Tianshan, Kyrgyzstan, and the other is the juncture of Jiashi （South Tianshan） and Pamir arc faults. In the above areas, it can be shown from the epicentral distribution that the strong earthquakes mostly occurs at the high shearing strain accumulation filed or its edge.

Upper mantle convection beneath northwest China and its adjacent region driven by density anomaly

We assume that the density anomalies, which are transformed from seismic tomography data, are corresponding to temperature distribution in a convective mantle. We take density anomalies as the driving force for mantle convection and solve the basic equation with given boundary conditions in a wave-number domain by using the FFT arithmetic. Using the physical model of upper mantle convection and the seismic tomography data supplied by XU et al, we calculated upper mantle convection beneath northwestern China and adjacent region. The flow patterns in the upper mantle show that there are upward and divergent flows in the basin regions, such as Tarim, Qaidam, Junggar and Kazakhstan, where the lithosphere is thin. There are downward and convergent flows in the mountain regions, such as Tianshan, Kunlun and Qilian, where the lithosphere is thick. In addition, because of the divergent flow under the Tarim Basin the upper mantle material in this region is driven southward to the north part of Tibetan Plateau and northward to Tianshan Mountain. Maybe, it is one of the reasons for the recent uplift of the Tianshaa Mountain.

Map of Mafic Dyke Swarms and Related Units of Russia and Adjacent Regions

Work is currently underway to produce a map in Arc GISTM 10 of the mafic dyke swarms and related units(volcanics,sills and layered intrusions)of Russia and adjacent regions at a scale of 1:5,000,000.Over the past

高技术产业创新活动对区域经济发展的驱动作用及其影响机制

厘清区域高技术产业如何赋能创新活动以助推地区经济发展,是提升区域发展整体效能、有效应对全球科技竞争的战略性问题。针对目前研发投资驱动的自主研发创新和外国直接投资驱动的跨国创新引入的作用机制及空间外溢的差异未明确,以及高技术产业技术市场化水平对不同创新活动经济效应的影响有待发掘的现状,将高技术产业科技密集度、技术市场化纳入创新驱动经济发展的研究框架,构建地理邻接矩阵和地理距离矩阵两种空间权重矩阵,以中国29个省份为研究对象,基于2011—2021年国家有关统计年鉴中的省级面板数据,运用动态空间杜宾模型实证分析自主研发创新、跨国创新引入对当地/邻近区域经济发展影响机制和空间外溢的差异性,探讨在高技术产业科技密集度及技术市场化水平的作用下,自主研发创新及跨国创新引入对经济发展的不同影响,并进一步分类对比分析高技术产业技术市场化水平、不同创新活动与区域经济发展的内在关系。结果表明:(1)区域创新活动水平与经济发展具有显著的空间依赖性,自主研发创新对经济发展的积极作用在长期内效果更明显,跨国创新引入对经济发展的积极作用在短期内效果更明显;(2)高技术产业科技密集度对当地的自主研发创新/跨国创新引入与经济发展之间的关系具有显著正向调节作用,且这一作用具有持久性;(3)随着高技术产业中技术市场化水平的提升,自主研发创新、跨国创新引入对区域经济发展的积极关系分别存在先下降后上升、先上升后下降的非线性变化,但这种正向作用整体力度呈现减弱趋势;(4)在科技密集区/欠密集区,随着高技术产业技术市场化水平的变化,不同创新活动对区域经济发展非线性影响的变化趋势虽然相同,但总体作用力度有所差异。最后从提高高技术产业的科技密集度和规范高新技术产业的技术市场化体系两方面提出相关对策建议。

基于Argos漂流浮标资料的南海及邻近海域次中尺度涡识别及特征分析

次中尺度涡作为连接中尺度涡和微小湍流之间的纽带,对海洋中能量串级和物质输运具有重要的影响。为研究南海及邻近海域次中尺度涡的分布特征和变化规律,本文开发了一种基于拉格朗日漂流轨迹几何特征的次中尺度涡识别方法,并对全球浮标计划中2000年至2022年进入研究海域的1 685个Argos漂流浮标轨迹数据进行了分析,共识别得到11 988个次中尺度涡。研究海域次中尺度涡的半径和生命周期呈正相关,多在3 km和24 h以内,反气旋涡与气旋涡数量之比约为5∶1。次中尺度涡高频出现于南海北部,由吕宋海峡西北部沿陆坡向西南方向递减。在中南半岛南部,次中尺度气旋涡相对更为活跃。研究海域次中尺度涡季节变化信号明显,冬、夏季相对活跃,春、秋季较少。

毗邻党建引领跨区域治理的运行机制与实践进路——基于成渝地区双城经济圈的考察

以党建引领基层治理是推进治理现代化的必由之路,毗邻党建模式为跨区域治理提供了新的思路与方法。为破解跨界治理中的边界效应难题和层级梗阻难题,成渝地区双城经济圈毗邻地区党组织不断增强和发挥其政治功能、组织功能,探索构建了毗邻党建引领跨区域治理的“动员—嵌入—协同”机制,以动员机制激发党建引领跨区域治理的思想动力,以嵌入机制增强党建引领跨区域治理的组织功能,以协同机制整合党建引领跨区域治理的发展资源,有效提升了两地跨区域治理的能力和水平。不过,实践中还存在“内生动力困境”“衔接落地困境”“集体行动困境”等问题。针对这些现实困境,要强化系统观念和问题导向,完善毗邻党建引领跨区域治理的领导机制;要创新组织设置和组织生活,夯实毗邻党建引领跨区域治理的工作基础;要推进制度建设和资源整合,健全毗邻党建引领跨区域治理的条件保障,只有这样才能进一步提升成渝地区双城经济圈毗邻党建引领跨区域治理的效能。

Watershed-based Image Segmentation with Region Merging and Edge Detection

The clustering technique is used to examine each pixel in the image which assigned to one of the clusters depending on the minimum distance to obtain primary classified image into different intensity regions. A watershed transformation technique is then employes. This includes: gradient of the classified image, dividing the image into markers, checking the Marker Image to see if it has zero points (watershed lines). The watershed lines are then deleted in the Marker Image created by watershed algorithm. A Region Adjacency Graph (RAG) and Region Adjacency Boundary (RAB) are created between two regions from Marker Image. Finally region merging is done according to region average intensity and two edge strengths (T1, T2). The approach of the authors is tested on remote sensing and brain MR medical images. The final segmentation result is one closed boundary per actual region in the image.

推进宁滁省际毗邻区域一体化发展研究

加强跨区域合作,探索省际毗邻区域一体化发展,是国家战略的要求,也是提升区域核心竞争力、实现高质量发展的使命所在。构建以毗邻示范区促县,以县促市,以市促圈,以圈成群的一体化传导机制,是推进长三角区域一体化发展的有效路径。近年来,宁滁省际毗邻区域在建立协作机制、基础设施互联互通、产业协同发展、环保联防联治等方面取得务实成效。随着南京都市圈毗邻地区的发展进入“快车道”,有必要对宁滁省际毗邻区域一体化发展存在的决策思维障碍、体制机制障碍进行系统梳理和分析,并研究解决问题的对策,为长三角更多毗邻地区一体化发展探索道路、提供战略指引。

黄土地区铁路近接路基变形分析及监测研究

黄土地区近接路基段由于施工难度大,牵制条件多,且新建线建设对既有线会产生附加影响,成为铁路建设工程中的控制性工程。以实际工程为背景,结合静动荷载力学模型,基于各阶段监测数据,研究近接路基变形规律。结果表明,既有线填筑阶段,沉降值随时间的增长逐渐增大,前期增长速率快,后期增长速率低,采用修正的Burgers模型可高度拟合;既有线运营阶段,沉降随运营时间的增加而增加,运营约2.5年时基本稳定,采用循环荷载下力学模型可高度拟合;新建线旋喷桩复合地基施工阶段,隆起量随各排高压旋喷桩施工均呈现先增加后波动性减小的现象,且当旋喷桩施工至距离顶面1/3~2/3位置时,对既有线影响最大;随着垫层及路堤本体填筑高度的增加,附加沉降值均随填筑高度增加和距离帮宽侧路肩长度减小呈现非线性增加。

Variations of stable isotopic compositions in precipitation on the Tibetan Plateau and its adjacent regions

There is no temperature effect in the southern Tibetan Plateau and South Asia to the south of the Tanggula Mountains. Amount effect has been observed at a few sampling stations accounting for about a half of the statistical stations. There is notable temperature effect in the middle and northern Tibetan Plateau and its adjacent Central Asia to the north of the Tanggula Mountains. Because vapor directly originates from low-latitude oceans, the relative heavy ( 18O with small variation characterizes the rainfall in South Asia. A sharp depletion of the stable isotopic compositions in precipitation takes place from Kyangjin on the southern slope of the Himalayas to the Tanggula Mountains in the middle plateau. From the Tanggula Mountains to the northern Tibetan Plateau, the ( 18O in precipitation increases with increasing latitude.

Diversity of Mesozoic tin-bearing granites in the Nanling and adjacent regions,South China:Distinctive mineralogical patterns

The Nanling and adjacent regions of South China host a series of tin deposits related to Mesozoic granites with diverse petrological characteristics. The rocks are amphibole-bearing biotite granites, or （topaz-） albite-lepidolite （zinnwaldite） granites, and geochemically correspond to mealuminous and peraluminous types, respectively. Mineralogical studies demonstrate highly distinctive and critical patterns for each type of granites. In mealuminous tin granites amphibole, biotite and perthite are the typical rock-forming mineral association; titanite and magnetite are typical accessory minerals, indicating highjO2 magmatic conditions; cassiterite, biotite and titanite are the principal Sn-bearing minerals; and pure cassiterite has low trace-element contents. However, in peraluminous tin granites zirmwaldite-lepidolite, K-feldspar and albite are typical rock-forming minerals; topaz is a common accessory phase, indicative of high peraluminity of this type of granites; cassiterite is present as a uniquely important tin mineral, typically rich in Nb and Ta. Mineralogical distinction between the two types of tin granites is largely controlled by redox state, volatile content and differentiation of magmatic melts. In oxidized metaluminous granitic melts, Sn4＋ is readily concentrated in Ti-bearing rock-forming and accessory minerals. Such Sn-bearing minerals are typical of oxidized tin granites, and are enriched in granites at the late fractionation stage. In relatively reduced peraluminous granitic melts, Sn2＋ is not readily incorporated into rock-forming and accessory minerals, except for cassiterite at fractionation stage of granite magma, which serves as an indicator of tin mineralization associated with this type of granites. The nature of magma and the geochemical behavior of tin in the two types of granites thus result in the formation of different types of tin deposits. Metaluminous granites host disseminated tin mineralization, and are locally related to deposits of the chlorite quartz-vein, greisen, and skarn types. Greisen, skarn, and quartz-vein tin deposits can occur related to peraluminous granites, but disseminated mineralization of cassiterite is more typical.

震源机制解谱聚类方法的研究及应用

多参数、多维度的震源机制解很难通过直观观察或简单的对比分析来进行有效的类型划分.谱聚类是一种基于谱图理论的聚类方法,对震源机制解这类非线性可分数据具有良好的划分效果.本文尝试使用该方法对震源机制解进行聚类分析,采用最小旋转角为相似度矩阵,利用规范割集准则(Ncut)完成类型判别,以间隔统计量法(Gap statistic)确定聚类数的最优解,从而对海量的震源机制解数据进行快速准确的类型划分.本文不仅通过一组随机样本数据集验证了这种方法的可行性和可靠性,还分别以海城M_(S)7.3地震序列和川滇及周边地区的震源机制解集作为研究对象,验证了此方法的实用性.结果表明,该方法合理细分了区域内的震源机制解类型,不同类型解之间的差异性主要体现在受不同的区域构造背景控制,有利于区域地震活动性的研究.总体上看,基于震源机制解的谱聚类方法是区分震源机制解类型较为有效的方法,具有一定的实用价值.

共同富裕目标下省际毗邻地区发展路径研究——基于政府间合作博弈视角

区域协调发展是实现共同富裕的必由之路。近年来,我国反复强调促进区域协调发展,加快构建新发展格局。作为区域协调发展的重要内容之一,省际毗邻地区的发展在推动共同富裕、建设统一大市场等方面发挥了重要作用。通过对省际毗邻地区发展问题的分析,发现涉及区域间的公共治理时,政府间的合作往往会陷入困局,加剧了省际毗邻地区的治理难题。因此,基于博弈论,本文分析了在不同的条件下,政府合作困局的形成机制,在此基础上梳理了推动省际毗邻地区发展的内在逻辑,提出破解困局的政策建议,为推动省际毗邻地区协调发展、实现全体人民共同富裕提供理论参考。