基于Elman型神经网络的金川二矿地表岩移时序预测模型

建立于煤矿开采基础之上的矿山开采沉陷理论和预测方法并不适用于象金川这样厚大、陡倾的金属矿床开采的岩移问题,因此,本文探讨利用神经网络来对地表岩移进行预测。根据Elman神经网络能够逼近任意非线性函数的特点和具有反映系统动态特性的能力,提出了利用Elman神经网络建立地表岩移时序预报模型的方法。利用金川二矿区GPS监测所得到的时间序列数据,通过对Elman神经网络模型预测值与GPS实测值之间的比较,结果表明模型预测显示了良好的准确性,特别是在时间步长较短情况下,应用于实际预测一定程度上可以弥补金属矿山岩移预测方法不足的缺憾。     

Study on Integrated Recurrence Behaviors of Strong Earthquakes Along Entire Active Fault Zones in the Sichuan-Yunnan Region, China

Based on historical earthquake data, we use statistical methods to study integrated recurrence behaviors of strong earthquakes along 7 selected active fault zones in the Sichuan-Yunnan region. The results show that recurrences of strong earthquakes in the 7 fault zones display near-random, random and clustering behaviors. The recurrence processes are never quasiperiodic, and are neither strength-time nor time-strength dependent. The more independent segments for strong earthquake rupturing a fault zone has, the more complicated the corresponding recurrence process is. And relatively active periods and quiescent periods for earthquake activity occur alternatively. Within the active periods, the distribution of recurrence time intervals between earthquakes has relatively large discretion, and can be modelled well by a Weibull distribution. The time distribution of the quiescent periods has relatively small discretion, and can be approximately described by some distributions as the normal. Both the durations of the active periods and the numbers of strong earthquakes within the active periods vary obviously cycle by cycle, leading to the relatively active periods having never repeated quasi-periodically. Therefore, the probabilistic assessment for middle- and longterm seismic hazard for entireties of active fault zones based on data of historical strong earthquakes on the fault zones still faces difficulty.     

柴达木盆地尕斯库勒盐湖地表水-地下水的转化与铀的补给通量

流域范围内地表水和地下水转化对盐湖成盐元素的运移和富集具有十分重要的意义.本文通过尕斯库勒盐湖盆地内流域水体的水化学和B同位素特征识别了地表水和地下水之间的定量转化关系,在此基础上估算了流域中铀的补给通量.结果表明,流域水体中离子的分异除了蒸发浓缩作用之外,还受重力分异及掺杂作用的影响;上游库拉木勒克萨伊河和阿特阿特坎河水体在出山口附近转入地下并在中游补给地表水和地下水,其补给率分别占48.8%和51.2%,年均补给量分别为1.08×108和1.13×108m3/a;在中游至尾闾盐湖段,阿拉尔河和侧向补给对盐湖卤水的补给率占55.2%,深部水体的补给占44.8%;至少从5.7 ka以来,上游水体对盐湖卤水中铀的补给通量为4.11×103t,在湖积平原黏土沉积带以及祁漫塔格山前局部还原带可能具有较大规模的铀矿.研究结果有助于建立盐湖盆地水循环模式、揭示卤水资源形成机制;同时为尕斯库勒盐湖盆地水资源的高效利用和寻找铀矿提供理论依据和技术支持.     

湘南骑田岭锡矿成矿规律探讨

骑田岭地区位于炎陵-郴州-蓝山北东向基底构造岩浆岩带中部,是南岭中段多金属成矿带的重要组成部分。现已查明111—333锡资源量101.3×104t,近期又发现了具超大型找矿前景的芙蓉锡矿田。锡矿类型可分为气化高温热液型锡矿、高—中温热液型锡矿、次火山热液型锡矿及冲积型砂锡矿四大类7个亚类,构成了一个较完整的成矿系列。各类锡矿是多次构造-岩浆活动综合作用的产物,燕山早期晚阶段及燕山晚期早阶段是主成矿期。特殊的地质构造背景造就了区内锡矿“带状分布、成群产出、等距展布”的空间分布规律,也展示了巨大的找矿潜力。     

基于ArcGIS的地震活断层多源数据组织与管理研究

"中国地震活动断层探测技术系统"获取的全国20多个重点城市多源地震探测数据,旨在满足城市地震抗震设防的空间数据基础建设以及城市发展规划、土地利用、重大工程选址应用的迫切需求,分析不同来源的地震探测数据特征,建立中国活动断层探测与地震危险性评价数据库的概念模型。在此概念模型上,结合ArcGIS的GeoDatabase模型给出了城市活动断层探测数据库具体逻辑模型,并按照地震系统确定的活动断层信息管理系统与基础数据库统一的建库标准和数据规范,实现多种活断层探测数据的统一整理和装载入库,完成了全国多个重点城市的活断层探测多源数据库建设,为"中国地震活动断层探测技术系统"各分工程的实施提供了数据保障和数据服务。     

鄂尔多斯块体周缘地区近期地震活动性与汶川地震应力触发作用的关系

采用β统计对汶川地震前后鄂尔多斯块体周缘地区的地震活动率进行了空间扫描分析,并采用JiChen的震源破裂模型计算了汶川地震产生的库仑破裂应力变化,以研究鄂尔多斯块体周缘地区近期地震活动性与汶川地震应力触发作用的关系。结果发现,鄂尔多斯块体西南缘弧形断裂束的南东段与南缘渭河盆地的地震活动率在汶川地震后提高显著,其他区域的地震活动率没有明显提高,库仑破裂应力计算得到两个区域的应力变化范围分别为0.005～0.02 MPa和0.001～0.01 MPa,表明汶川地震有可能触发了这两个区域的地震活动。鄂尔多斯块体东缘的山西断陷带处于库仑破裂应力计算的应力增加区,应力变化范围为0～0.012 MPa,2009年3月以来发生的4次ML4.5～5.2级强有感至微破坏地震有可能被汶川地震所延迟触发。b值、地震能量释放率与空间相关距离SCL等地震活动性参数随时间变化扫描结果显示,该区域可能处于不断趋近高应力累积的状态,其未来大震有可能提前发生。西缘地区为应力减小区,其目前的地震活动处于正常水平状态。     

日本横手盆地东缘陆羽逆断层系的同震地表破裂特征及其分段性

通过对陆羽逆断层系上１８９６年同震地表破裂特征、长期活动习性和断错地貌等的研究，给出了可识别的逆断层型段落边界的标志，它们是断层崖形态持久性变化的过渡地段、断层抬升盘山地分水岭高程明显变化的转折部位、剖面几何结构转换区和断层下降盘盆地内的隐伏横向基岩脊等；指出逆断层上公里量级的空缺和阶区不能有效地终止或延缓逆断层型同震地表破裂的横向扩展，因此，不能作为逆断层型段落的边界，最后对陆羽逆断层系的千屋段和横手段的地震危险性进行了简要评估     

芦山地震发震构造及其与汶川地震关系讨论

芦山地震发生在巴彦喀拉块体与华南块体之间龙门山推覆构造带南段。野外考察表明,芦山地震在震中区没有形成具有构造地质意义的地震地表破裂带,仅在各山前陡坡地带出现平行于山麓陡坡的张性地裂缝、山地基岩崩塌、滑坡等边坡震动失稳现象和震动引起的砂土液化现象。重新定位的芦山地震余震分布、震源机制解和地表构造地质等分析表明,芦山地震的发震断层为一条现今尚未出露地表、其上断点仍埋藏在地下9 km以下地壳中的一条盲逆断层,走向212°,倾向NW,倾角38°±2°,上断点以上至地表的构造变形符合断层扩展背斜模型。根据汶川地震和芦山地震的余震空间分布、地震破裂过程、深浅构造关系等差异反映出它们是分别发生在龙门山推覆构造带中段和南段的两次独立地震破裂事件。     

Application of an incomplete landslide inventory, logistic regression model and its validation for landslide susceptibility mapping related to the May 12, 2008 Wenchuan earthquake of China

The main purpose of this paper is to present the use of multi-resource remote sensing data, an incomplete landslide inventory, GIS technique and logistic regression model for landslide susceptibility mapping related to the May 12, 2008 Wenchuan earthquake of China. Landslide location polygons were delineated from visual interpretation of aerial photographs, satellite images in high resolutions, and verified by selecting field investigations. Eight factors, including slope angle, slope aspect, elevation, distance from drainages, distance from roads, distance from main faults, seismic intensity and lithology were selected as controlling factors for earthquake-triggered landslide susceptibility mapping. Qualitative susceptibility analyses were carried out using the map overlaying techniques in GIS platform. The validation result showed a success rate of 82.751 % between the susceptibility probability index map and the location of the initial landslide inventory. The predictive rate of 86.930 % was obtained by comparing the additional landslide polygons and the landslide susceptibility probability index map. Both the success rate and the predictive rate show sufficient agreement between the landslide susceptibility map and the existing landslide data, and good predictive power for spatial prediction of the earthquake-triggered landslides.