Fault structures and their geoelectric parameters in the epicentral zone of the 27 September 2003 Chuya earthquake (Gorny Altai) from resistivity data

This paper presents an integrated measurement technique based on DC methods (vertical electrical sounding, electrical resistivity tomography) which was used to identify faults and determine their geoelectric parameters in the western part of the Chuya basin. New information on the structure of the Chagan River valley located in the zone of the disastrous 27 September 2003 Chuya earthquake has been obtained from the results of these methods. Geoelectric cross-sections of the sedimentary sequence and the upper part of the basement were obtained from VES data, showing the block structure of the study area. Electrical resistivity tomography sections confirm the presence of a major fault between basement blocks of different heights and indicate the presence of faults bounding the valley on its right side and in the southwestern part.     

常量元素氧化物含量及其比值揭示的中晚全新世以来玛曲高原的环境演变

对玛曲高原具有代表性的黄土-古土壤-风成砂剖面(OL剖面)常量元素氧化物含量及其比值的地球化学特征分析表明:(1)常量元素氧化物总含量为91.93%且SiO₂(67.93%) >Al₂O₃(11.2%) >Fe₂O₃(3.97%) >CaO(3.76%)>K₂O(2.16%) >Na₂O(1.81%) >MgO(1.1%);(2)玛曲高原处于较弱的脱Ca、Na初级风化阶段,并伴有碳酸盐的淋失;(3)玛曲高原的气候经历了冷干-凉润-温湿-凉干的冷暖旋回。依据常量元素氧化物含量及其比值揭示的环境特征并结合¹⁴C测年将玛曲高原中晚全新世以来的环境演变划分为4.6 ka BP以前的风沙活动强烈期、4.6～4.3 ka BP的风沙活动较弱期、4.3～0.3 ka BP的固结成壤期和0.3 ka BP至今的风沙活动增强期4个阶段。     

Habitat modeling for health sovereignty: Increasing indigenous access to medicinal plants in northern Maine,USA

Medicinal plants and fungi play important roles in the health of Maliseet people of northern Maine, USA. A critical aspect of exercising choice in health care for this community is the ability to locate and have access to these plants. Habitat suitability modeling is a form of geospatial technology that can enhance health sovereignty by identifying locations in which populations of medicinal plants can be conserved or established. However, use of this technology within indigenous communities has been limited. Focusing on the medicinal plant muskrat root, Acorus americanus (Raf.) Raf., we generate a habitat suitability model for eastern Aroostook County, Maine (1,055,653.659 ha) that also takes community needs into consideration. Drawing on participatory ethnographic data as well as environmental characteristics, our model combines ecological and sociocultural parameters to identify previously unknown populations of A. americanus that are accessible to tribal elders. Our model successfully predicted 95% of A. americanus locations in our field validation data set of ∼71,000 ha. Results suggest that approximately 0.6% of our study area contains suitable habitat to plant muskrat root that could also meet tribal members' gathering needs for the future. Increasing the number of potential collection sites gives communities options for gathering, thereby enhancing health sovereignty. Broadly, our work suggests that, when done in partnership with communities, different forms of geospatial technology can be beneficial tools for efforts to promote health sovereignty.     

天山北坡高山林线分布的生态地理特征

综合利用多源遥感影像和实地勘察资料识别天山北坡高山林线分布格局,结合区域气象数据和土壤理化性质,分析天山北坡林线分布的生态地理特征。结果表明:①天山北坡林线分布高度大约在2 600～2 850 m,从西向东林线分布高度呈上升趋势,奇台至巴里坤段林线高度上升最为显著;伊犁河谷段与玛纳斯段林线垂直宽度较宽。②影响天山北坡林线分布高度的关键气候因子为生长季温度（如年生物学温度3.35 ℃,最热月均温10.49 ℃,生长季均温8.26 ℃）,特别是年生物学温度,能较好的指示天山北坡高山林线分布位置,且各气候指标均在全国均值范围之内,而影响巴音布鲁克地区森林发育的主要原因为冬季低温干旱。③伊犁林线过渡带和玛纳斯林线过渡带有机质、全氮及全磷的含量最高;酸碱性大致以阜康林线为界,向西呈酸性,向东呈碱性;土壤营养物质主要分布于表层（0～10 cm）,深层(30～80 cm)含量低且变化不显著,具有明显的“表聚现象”;下层土壤pH值从西向东逐渐由弱酸性向弱碱性过渡;电导率空间变异性较强,各层变化特征不显著。     

Automatic mapping of lunar landforms using DEM-derived geomorphometric parameters

Developing approaches to automate the analysis of the massive amounts of data sent back from the Moon will generate significant benefits for the field of lunar geomorphology. In this paper, we outline an automated method for mapping lunar landforms that is based on digital terrain analysis. An iterative self-organizing (ISO) cluster unsupervised classification enables the automatic mapping of landforms via a series of input raster bands that utilize six geomorphometric parameters. These parameters divide landforms into a number of spatially extended, topographically homogeneous segments that exhibit similar terrain attributes and neighborhood properties. To illustrate the applicability of our approach, we apply it to three representative test sites on the Moon, automatically presenting our results as a thematic landform map. We also quantitatively evaluated this approach using a series of confusion matrices, achieving overall accuracies as high as 83.34% and Kappa coefficients (K) as high as 0.77. An immediate version of our algorithm can also be applied for automatically mapping large-scale lunar landforms and for the quantitative comparison of lunar surface morphologies.     

Sensitivity of soil parameters in unsaturated zone modelling and the relation between effective,laboratory and in situ estimates

Simulation of soil moisture content requires effective soil hydraulic parameters that are valid at the modelling scale. This study investigates how these parameters can be estimated by inverse modelling using soil moisture measurements at 25 locations at three different depths (at the surface, at 30 and 60 cm depth) on an 80 by 20 m hillslope. The study presents two global sensitivity analyses to investigate the sensitivity in simulated soil moisture content of the different hydraulic parameters used in a one‐dimensional unsaturated zone model based on Richards' equation. For estimation of the effective parameters the shuffled complex evolution algorithm is applied. These estimated parameters are compared to their measured laboratory and in situ equivalents. Soil hydraulic functions were estimated in the laboratory on 100 cm³ undisturbed soil cores collected at 115 locations situated in two horizons in three profile pits along the hillslope. Furthermore, in situ field saturated hydraulic conductivity was estimated at 120 locations using single‐ring pressure infiltrometer measurements. The sensitivity analysis of 13 soil physical parameters (saturated hydraulic conductivity (K_s), saturated moisture content (θ_s), residual moisture content (θ_r), inverse of the air‐entry value (α), van Genuchten shape parameter (n), Averjanov shape parameter (N) for both horizons, and depth (d) from surface to B horizon) in a two‐layer single column model showed that the parameter N is the least sensitive parameter. K_s of both horizons, θ_s of the A horizon and d were found to be the most sensitive parameters. Distributions over all locations of the effective parameters and the distributions of the estimated soil physical parameters from the undisturbed soil samples and the single‐ring pressure infiltrometer estimates were found significantly different at a 5% level for all parameters except for α of the A horizon and K_s and θ_s of the B horizon. Different reasons are discussed to explain these large differences. Copyright © 2004 John Wiley & Sons, Ltd.     

利用SEM照片获取土的孔隙结构参数

以土工实验和计算机图像处理技术为基础, 探讨利用SEM照片获取土的孔隙结构参数的方法, 并以重塑粘性土为例进行实证分析.为获取孔隙结构参数, 首先分3个步骤对土样的SEM照片进行图像处理: 即照片格式转换、颗粒边际线探测和颜色充填; 然后针对黑白二元图像测算孔隙结构参数.从设计制备的重塑粘性土的三轴试验样品中, 选择了12个不同水分状态和密度状态的样品, 经风干和烘干后, 进行SEM测试, 每个样品拍摄了3个尺度的SEM照片, 放大倍数依次为500倍、1000倍、2000倍.之后, 对所获得的SEM照片进行了图像处理分析, 计算了相应的平面孔隙比和平面孔隙率.数据分析表明: SEM照片测算的孔隙参数与通常三相图计算的孔隙参数有关联, 测算数据可以反映土的孔隙结构特征; 样品的不同脱水方式对SEM照片测算的孔隙参数有影响, 与三相图法计算数据相比, 风干土样测算的数据略有偏大, 烘干土样测算的数据偏小; 同一土样不同比例尺的SEM照片测算出的孔隙参数有所不同, 邻近三相图法计算结果上下波动; 利用SEM照片提取土的结构信息是可行的, 对SEM照片进行图像处理分析是获取土的孔隙结构参数的有效办法.