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Fractal and Multifractal Propertiesof the Spatial Distribution of Natural Fractures——Analyses and Applications

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Acta Geologica Sinica(English Edition) 1999年第4期73卷 477-487页

作者： xu jiandong QU Guosheng Robert D. JACOBI Institute of Geology China Seismological Bureau Beijing 100029 PRC Department of Geology State University of New York at Buffalo USA

The Cantor's dust theory is applied to investigate the scaling properites of the spatial distribution of natural fractures obtained from detailed scanline surveys of 27 field sites in the Appalachian Plateau of western New York, USA. The results obtained in this study indicate: 1) fracture spacing is characterized by fractal and multifractal properties. On small scales analyses yield an average fractal dimension of 0.15, which suggests a very high degree of clustering. In contrast, on large scales, fractures tend to be more regular and evenly distributed with an average fracture dimension of 0.52; 2) fractal dimension varies with different sets in different orientations, which can be attributed to interactions between pre-existing fractures and younger ones, as well as variations of the intensity of the stresses under which the fractures were formed; 3) a time sequence of fracture set formation can be proposed based on fractal and multifractal analyses, which consists of (from old to young): N-S, NW, ENE, and NE-striking sets. This time sequence is confirmed by the study of the abutting relationships of different fracture sets observed in the field.

关键词： fractal multifractal fracture

Application of satellite thermal infrared remote sensing in monitoring magmatic activity of Changbaishan Tianchi volcano

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Chinese Science Bulletin 2010年第24期55卷 2731-2737页

作者： JI LingYun xu jiandong LIN xuDong LUAN Peng Institute of Geology China Earthquake Administration Beijing 100029 China The Second Crust Monitoring and Application Center China Earthquake Administration Xi'an 710054 China Chinese Academy of Land and Resource Economies Beijing 101149 China

In this paper, with the application of satellite thermal infrared remote sensing technique, nine land surface temperature distribution maps of Changbaishan Tianchi volcano area are retrieved from nine thermal infrared images which are taken from 1999 to 2008. In terms of NDVI (Normalized Difference Vegetation Index), we classify the surface cover of the study area into three types, i.e. vegetation (forest), mixture of soil and vegetation (short grasses), and bare rock. The average temperature of each type of surface covers is calculated first, and then the average daily temperature record from Tianchi meteorological station is subtracted in order to reduce the effect of weather variation. Finally, thermal anomalies of three types of surface cover in Changbaishan Tianchi vol-cano area in the period of 1999 to 2008 are obtained, which is believed to reflect the magmatic activity in the magma chamber under Tianchi volcano caldera. Our results indicate that temperature of the study area increased with an intermittent tendency during 1999 to 2005, but dropped after 2005, and then maintained a relatively stable state from 2006 to 2008. Such a tendency of annual temperature variation possibly caused by magmatic activity is correlated with the results observed by means of seismic monitoring, ground deformation from GPS measurement, and volcanic gas geochemistry monitoring in the same area. It is im-plied that the upward intrusion of magma may cause temperature increase, and such temperature variation is great enough so that could be detected by using satellite thermal infrared remote sensing technology.

关键词：卫星热红外遥感火山岩浆活动长白山天池遥感监测归一化植被指数应用表面平均温度天池火山区

Magmatic Processes of Ashi Volcano, Western Kunlun Mountains, China

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Acta Geologica Sinica(English Edition) 2014年第2期88卷 530-543页

作者： YU Hongmei xu jiandong ZHAO Bo SHEN Huanhuan LIN Chuanyong Key Laboratory of Active Tectonics and Volcano Institute of GeologyChina Earthquake Administration

The Ashikule volcanic cluster （AVC） in western Kunlun Mountains is located in a graben region at the convergence of the Altun and Kangxiwa fault zones,and consists of more than 10 main volcanoes and dozens of *** Ashi volcano lies in the central part of the volcanic *** lithology,chemical composition and texture of Ashi volcanic rocks were studied in detail,and their implication in magmatic processes was *** phenocrysts in Ashi volcanic rocks consist mainly of plagioclase and pyroxene,and the statistical results of phenocryst contents show that the rocks can be subdivided into two *** group A,the content of pyroxene phenocrysts is generally higher than that of plagioclase phenocrysts,but an inverse relation occurs in group *** TAS diagram,the compositions of both groups fall into the trachyandensite field,but they are obviously concentrated into two *** two clusters exist also in the oxide *** pyroxene phenocrysts comprise augite,bronzite and hypersthene,and their Mg# histogram shows two *** phenocrysts with reaction rim are observed in rocks of both *** An values of the core are generally 30-40,and those of the rim are 44-48,which are closer to those of euhedral *** bronzites are in equilibrium with the melt,and two sets of magma depths,i.e.,18-25 km and 13-18 km,can be estimated by using thermobarometer proposed by *** hypersthenes are not in equilibrium with the melt,and can be assigned to *** crystal size distribution （CSD） curves of plagioclase appear as kinked lines indicative of magma *** above analyses show that two magma pockets might exist beneath the Ashi *** is likely that they are connected with each *** one has more evolved and contains more acidic magma,and the other is a trachyandensite magma pocket characterized by *** magma from the upper part of the trachyandensite magma pocket might mix with more acidic magma,r

关键词： texture chemical composition crystal size distribution Ashi volcano Ashikule volcanic cluster

Semi-crosslinked polyacrylamides as high-resolution and dynamic self-coating sieving matrices for protein capillary electrophoresis

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Chinese Science Bulletin 2008年第19期53卷 2953-2957页

作者： ZHOU Jin xu jiandong XIE Yao QU Feng DENG YuLin GENG LiNa School of Life Science and Technology Beijing Institute of Technology Beijing 100081 China

This paper describes non-gel capillary sieving electrophoresis employing semi-crosslinked polyacrylamide as a high performance and low viscous replaceable separation matrix for separation of non-denatured protein separation. Arising from the fine sieving and dynamic coating ability of this polymer, a mixture of basic proteins lysozyme, cytochrome C, ribonuclease A, and trypsin was resolved with excellent reproducibility. Mixing different semi-crosslinked polyacrylamides together further improves the separation. The separtion mechanism was analyzed. With network structure developed to an intermediate state between crosslinked gel and linear polymer solutions, these semi-crosslinked polyacrylamide polymers demonstrate a promise as a new class of size sieving separation medium, not only in capillary electrophoresis, but also in microfluidic chip separation schemes.

关键词：毛细管筛子电泳聚丙烯酰胺蛋白质分离

Characteristics and origin of mafic and ultramafic xenoliths in trachyandesite lavas from Heikongshan volcano,Tengchong,Yunnan Province,China

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Science China Earth Sciences 2010年第9期53卷 1295-1306页

作者： YU HongMei, LIN ChuanYong, SHI LanBin, xu jiandong & CHEN XiaoDe Institute of Geology, China Earthquake Administration, Beijing 100029, China 1. Institute of Geology China Earthquake Administration Beijing 100029 China

The trachyandesite lavas from Heikongshan volcano of the Tengchong volcanic cluster, Yunnan Province contain relatively abundant mafic and ultramafic small xenoliths comprising mainly gabbro, pyroxenite and rare lherzolites, all less than 2.5 cm in size. Gabbro xenoliths are characterized by "open" texture represented by relatively abundant vesicles and ground-mass fillings, while pyroxenite xenoliths are characterized by equigranular and poikilitic texture. Their mineral compositions (clinopyroxene ± orthopyroxene ± plagioclase) are similar to those of phenocrysts in lavas, and their equilibration temperature (1000-1125°C) is consistent with the crystallization temperature of the phenocrysts (998-1108°C). Thus, the textures and compositions of these xenoliths are different from those of lower crustal and mantle xenoliths, and were derived from the magma chamber. Among them, the gabbroic xenoliths come from the crystal-bubble-liquid zone at the top of the magma reservoir, while the pyroxenite xenoliths come from the cumulates in the bottom of magma reservoir. The studied single lherzolite xenolith with porphyroclastic texture has similar mineral compositions to the mantle xenoliths from eastern China, and is considered to be of upper mantle origin. It was brought into magma reservoir by replenishment magma, and might have experienced a cooling event before eruption. The formation of xenoliths in trachyandesite flows largely reflects the ascent, storage, evolution and eruption processes of magma.

关键词： magma chamber xenoliths geothermo-barometry trachyandesite Heikongshan volcano Tengchong

Volcanic Hazard Mapping for Changbaishan-Tianchi Region,China

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Journal of Earth Science 2024年第6期35卷 2030-2044页

作者： Yuan Wan jiandong xu Bo Pan Jingwei Zhang Hongmei Yu Bo Zhao Feixiang Wei Jilin Changbaishan Volcano National Observation and Research Station Institute of GeologyChina Earthquake AdministrationBeijing100029China

Volcanic hazard zoning is an effective way to reduce and mitigate volcanic *** to its frequent magmatic unrest and potential for catastrophic eruption,the Changbaishan-Tianchi Volcano is currently the focus of attention for volcanic disaster prevention in *** study uses past eruption data obtained from geological surveys and geochronological studies,to construct simulations of tephra fall,pyroclastic flows,lava flows,and *** widely accepted numerical models were adopted to simulate each hazard at different eruption *** zoning was then conducted,producing a comprehensive hazards map of the Changbaishan-Tianchi *** map identifies areas of high,medium,and low hazard,mostly at 0-15,15-60,60-100 km from the *** work serves as the scientific basis for the authorities and general public in the areas around the Changbaishan-Tianchi Volcano in planning for future response,as well as provides a reference for hazard zoning in other areas potentially affected by volcanic hazards.

关键词： Changbaishan-Tianchi Volcano active volcano numerical models hazards mapping

Field Geological Exploration of the Ashikule Volcano Group in Western Kunlun Mountains

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Earthquake Research in China 2012年第2期26卷 I0003-I0003,153-159页

作者： xu jiandong Zhao Bo Zhang Liuyi Chen Zhengquan Key Laboratory of Active Tectonics and Volcano Institute of Geology CEA Beijing 100029 China College of Resource Environment and Tourism Capital Normal University Beijing 100048 China

From May 4 to May 30, 2011, a field exploration of the Ashikule basin in the Western Kunlun Mountains area was conducted by a research team from the Institute of Geology, China Earthquake Administration and Earthquake Administration of Xinjiang Uygur Autonomous Region. This work is financially supported by the special fund for China earthquake research project "The Comprehensive Scientific Exploration of the MS7.3 Yutian Earthquake in 2008 and the Ashikule Volcano Group". Through detailed field survey on geological and geomorphological features of the Ashikule volcano group, which is one of the highest altitude volcanic plateaus (about 5000m) in the world, we have determined the total number of volcanoes, the eruption type and structural parameters, and approximate active history of the volcano group. Our studies have provided field evidence for resolving past controversies such as the authenticity of the news report about the eruption event on May 27, 1951, the eruption pattern of the Daheishan volcano, and the reality of the Gaotaishan volcano.

关键词： Ashikule volcano group Recent eruption Volcano cone Lava

Simulation of Near-Fault Strong Ground Motion in the Beijing Region

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Earthquake Research in China 2007年第3期21卷 281-292页

作者： Pan Bo xu jiandong Haruko Sekigguchi He Honglin Institute of Geology China Earthquake Administration Beijing 100029 China Active Fault Research Center Tsukuba Ibaraki 305-8567 Japan

On the basis of previous study of the 1679 Sanhe-Pinggu(M8.0) earthquake,the biggest event in history ever recorded in Beijing and its adjacent area,we made a 3-D strong ground motion simulation utilizing the staggered-grid finite differences method to study the distributions of peak ground velocity with different earthquake source models in the Beijing *** the paper,earthquake source models and a transmission medium velocity model are established and the corresponding parameters are given in accordance to the results from a related previous ***,using a three-dimensional finite difference computing program of near-fault strong ground motion developed by Graves,the peak ground velocity caused by a destructive earthquake in the Beijing area is *** our computation model,the earthquake source is 3km in depth,and a total number of 21,679 observation points on the ground surface are figured *** transmission medium velocity model is composed of four stratums which are the Quaternary deposit,the upper crust,the upper part of the middle crust and the lower part of the middle *** the minimum grid spacing of 0.15km,a total of 2.28×106 grids are *** a time step of 0.02 seconds we calculated the peak ground velocity for a duration of 8 *** the analysis of the simulation results,we observed some basic characteristics of near-fault strong ground motion such as the concentration effect of near-fault peak ground velocity,rupture directivity effect,hanging wall effect,and basin *** results from our simulation and analysis suggest that the source and transmitting medium parameters in our model are suitable and the finite difference method is applicable to estimate the distribution of strong ground motion in the study region.

关键词： Strong ground motion Source parameter Transmitting medium parameter Concentration effect Rupture directivity effect Hanging wall effect, basin effect

Numerical Simulation and Probabilistic Hazard Assessment of Tephra Fallout at Jinlongdingzi Volcano,Longgang Volcanic Field in Jilin Province

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Earthquake Research in China 2013年第3期27卷 391-400页

作者： Yu Hongmei xu jiandong Wu Jianping Luan Peng Zhao Bo Institute of Geophysics China Earthquake Administration Key Laboratory of Active Tectonics and Volcano Institute of GeologyCEA Chinese Academy of Land and Resource Economics

Tephra fallout is an important type of hazard caused by explosive volcanic eruption, and numerical simulation has become a fast and effective approach to assess the dispersion and deposition of tephra fallout. According to the improved 2D diffusion model of Suzuki （ 1983）, we edited a tephra diffusion program that can run in the Windows system. Based on previous data, we simulated the diffusion scope of the Jinlongdingzi volcanic eruption, which is the latest eruption in the Longgang volcanic cluster. The simulated results are in good agreement with the results from measurement in situ, indicating that the model is reliable and the parameters used in the model are suitable. By using wind profiles of ten years, 7, 021 simulations under different wind profiles were carried out, and then probabilistic hazard maps of tephra fallout were constructed for tephra thickness thresholds, lcm and 0.5cm. This study can provide an important scientific basis for volcanic hazard analysis, risk mitigation plans and countermeasures in the Longgang volcanic area.

关键词： Tephra fallout Numerical simulation Hazard probability maps Jinlongdingzi volcano Longgang volcanic cluster