Triggered earthquakes and deep well activities

Earthquakes can be triggered by any significant perturbation of the hydrologic regime. In areas where potentially active faults are already close to failure, the increased pore pressure resulting from fluid injection, or, alternatively, the massive extraction of fluid or gas, can induce sufficient stress and/or strain changes that, with time, can lead to sudden catastrophic failure in a major earthquake. Injection-induced earthquakes typically result from the reduction in frictional strength along preexisting, nearby faults caused by the increased formation fluid pressure. Earthquakes associated with production appear to respond to more complex mechanisms of subsidence, crustal unloading, and poroelastic changes in response to applied strains induced by the massive withdrawal of subsurface material. As each of these different types of triggered events can occur up to several years after well activities have begun (or even several years after all well activities have stopped), this suggests that the actual triggering process may be a very complex combination of effects, particularly if both fluid extraction and injection have taken place locally. To date, more than thirty cases of earthquakes triggered by well activities can be documented throughout the United States and Canada. Based on these case histories, it is evident that, owing to preexisting stress conditions in the upper crust, certain areas tend to have higher probabilities of exhibiting such induced seismicity.     

甘肃省席芨水地区遥感蚀变信息提取及找矿远景分析

在地质工作程度较低、基岩出露较好的地区,充分重视遥感数据的使用,可有效地缩小工作靶区,提高找矿效率。该文以甘肃省席芨水地区为研究区,基于ETM+遥感数据,利用多元数据分析、准归一化、掩膜分析、主成分分析、密度分割等方法,从Landsat7ETM+数据中提取金矿化蚀变信息。在遥感地质解译的基础上,充分分析提取的羟基异常和铁染异常,结合区域地质特征、区域成控矿条件及区域物化探异常特征等,尽可能去掉假、弱异常。结果表明:该方法能有效消除植被、水系、阴影等干扰信息的影响,从遥感数据载体中提取微弱的金矿化蚀变信息。提取的矿化蚀变信息与断裂构造具有较好的相关性,主要分布于断裂构造交会处、断裂与岩体交会处等成矿优势部位,对今后的找矿工作具有一定的指导意义。     

面向带电作业的手臂末端输出力评估方法

为了解决带电作业时手臂末端输出力的准确控制,提出一种基于表面肌电信号（sEMG信号）和支持向量机回归（SVR）实现对手臂末端施力的评估方法.通过手握机械手臂末端的手柄,做往复推拉运动,记录此时手柄处的力传感器的数据F,同时利用3组肌电信号传感器同步采集手臂的肌电信号.将肌电信号提取特征后,与力F组合成样本集合S,在样本集合中随机抽取50%的样本数据作为训练集,分别训练BP神经网络、GRNN神经网络以及SVR神经网络.最后用训练好的神经网络对整个样本集中的力F进行预测,并用均方根误差和相关系数评估模型的预测效果.结果显示,SVR神经网络的预测效果较好,其均方根误差为3.074 0,相关系数为0.951 7.     

基于弹性薄板的地表沉陷预计模型

在分析地表沉陷基本规律的基础上,依据弹性薄板理论,建立非充分采动条件下岩层和地表沉陷预计的一类新模型,并推导出地表任意点倾斜、曲率、水平移动以及水平变形的计算公式。该模型充分考虑到地质采矿因素（煤层倾角）及煤层上方各岩层的影响,克服传统预测方法的缺陷,特别是概率积分法关于拐点反对称要求。最后,应用实例证明该方法的应用效果。     

车辆轨迹数据的道路学习提取法

车辆轨迹数据的道路信息提取是地理信息领域的热点也是难点之一,深度学习的快速发展为该问题的解决提供了一种思路与方法。本文针对车辆轨迹数据的车行道级道路提取问题,引入深度学习领域的生成式对抗网络,利用残差网络构建深层网络和多尺度感受野感知轨迹数据不同细节特征,构建了基于条件生成式对抗网络的轨迹方向约束下车行道级道路提取模型。首先提出了朝向-颜色映射栅格化转换方法,实现轨迹朝向信息向HSV颜色空间的转换;然后利用样本数据学习模型参数;最后将训练模型应用到郑州、成都、南京3个试验区域提取车行道级道路数据。试验结果表明,本文方法能够有效地提取完整的车行道级道路数据。     

Accuracy improvement of ASTER stereo satellite generated DEM using texture filter

The grid DEM(digital elevation model) generation can be from any of a number of sources:for instance,analogue to digital conversion of contour maps followed by application of the TIN model,or direct elevation point modelling via digital photogrammetry applied to airborne images or satellite images.Currently,apart from the deployment of point-clouds from LiDAR data acquisition,the generally favoured approach refers to applications of digital photogrammetry.One of the most important steps in such deployment i...     

云南先峰中新世木乃伊化木化石α-纤维素的提取

本文对云南先锋中新世木乃伊化木化石进行α-纤维素实验提取,以验证化石纤维素的可得性。实验利用有机溶剂分离、碱液分离、无机酸分离等方法分别对研究区5件木乃伊化化石样品进行处理,并采用红外光谱检测方法与现代木材α-纤维素和国际标准α-纤维素进行对比试验。实验结果显示,3种提取方法均可以从化石木材中提取出α-纤维素,但过程特征各有不同。其中,有机溶剂分离实验过程耗时最长,碱液分离方法样品损失最大。相比之下,无机酸分离方法对于木乃伊化木化石α-纤维素提取的效率最高。     

遥感技术提取海岸线的研究进展

海岸带是比较活跃和脆弱的地段,快速而准确地监测海岸线的动态变化对于海域的使用管理具有十分重要的意义.遥感技术具有宏观、快速、综合、高频、动态和低成本等突出优势.重点介绍了利用阈值分割、边缘检测、色差算子提取、区域生长提取及神经网络分类等方法自动提取瞬时水边线,通过潮位校正进而提取海岸线的研究进展,分析了各种提取方法的优缺点,并就其存在的不足展望了今后的研究方向.     

A modified analytical method for the shipboard determination of nanomolar concentrations of orthophosphate in seawater

A method for the determination of nanomolar concentrations of orthophosphate in oligotrophic seawater developed by Liang et al. (2007) has been modified to make it fully feasible for shipboard application and for faster sample throughput with minimized sample volume. The technique is based on the flow injection method with solid phase extraction on a Sep-Pak C18 cartridge and colorimetric detector. The Schlieren effect was minimized by rinsing the cartridge sequentially with 5 mL water and 2 mL 95% ethanol solution. With three micro pumps in parallel, savings of up to 80% in amount of reagents and 25% volume of seawater samples could be achieved in comparison to the previous method. Variation of stopped flow time and sample loading time gave 3 different standard curves, which corresponded to 3 linear ranges within 3.4 and 515 nM. The modified method permits the analysis of samples over a wide range of concentrations, and has been successfully applied to shipboard determination of trace orthophosphate in more than 200 seawater samples during a one-month cruise in the South China Sea. For seawater at concentrations of 20.6, 82.5, 206.2 nM orthophosphate, the relative standard deviations (RSD) (n = 6), determined daily for 6 days on board ship were 4.45%, 4.73% and 6.75%, respectively. Five seawater samples collected in the Station SEATS (South East Asia Time Series Station at 18°N, 116°E) were analyzed using the present method both on board and in a land-based laboratory, as well as with the magnesium hydroxide-induced coprecipitation (MAGIC) method, and showed no significant difference according to the statistical t-test.     

Data-driven modelling approaches for socio-hydrology: opportunities and challenges within the Panta Rhei Science Plan

ABSTRACT

“Panta Rhei – Everything Flows” is the science plan for the International Association of Hydrological Sciences scientific decade 2013–2023. It is founded on the need for improved understanding of the mutual, two-way interactions occurring at the interface of hydrology and society, and their role in influencing future hydrologic system change. It calls for strategic research effort focused on the delivery of coupled, socio-hydrologic models. In this paper we explore and synthesize opportunities and challenges that socio-hydrology presents for data-driven modelling. We highlight the potential for a new era of collaboration between data-driven and more physically-based modellers that should improve our ability to model and manage socio-hydrologic systems. Crucially, we approach data-driven, conceptual and physical modelling paradigms as being complementary rather than competing, positioning them along a continuum of modelling approaches that reflects the relative extent to which hypotheses and/or data are available to inform the model development process.

EDITOR D. Koutsoyiannis; ASSOCIATE EDITOR not assigned