跨断层测量不等间隔计算的数据匹配

跨断层测量的数据处理中,常利用不等间隔数据进行计算,由此产生一系列问题,如时间计算、同步性、主从关系、可比性等。对此,从合理、最佳的要求出发,以约定的方式进行设计,考察它们在多种算法中的适应能力,有利于跨断层测量数据处理的完善和发展。
     

RUPTURE CHARACTERISTICS OF LATE QUATERNARY STRONG EARTHQUAKES ON THE WESTERN BRANCH OF THE XIAOJIANG FAULT ZONE

The Xiaojiang fault zone is located in the southeastern margin of the Tibetan plateau, the boundary faults of Sichuan-Yunnan block and South China block. The largest historical earthquake in Yunnan Province, with magnitude 8 occurred on the western branch of the Xiaojiang Fault in Songming County, 1833. Research on the Late Quaternary surface deformation and strong earthquake rupture behavior on the Xiaojiang Fault is crucial to understand the future seismic risk of the fault zone and the Sichuan-Yunnan region, even crucial for the study of tectonic evolution of the southeastern margin of Tibetan plateau. We have some new understanding through several large trenches excavated on the western branch of the Xiaojiang fault zone. We excavated a large trench at Caohaizi and identified six paleoseismic events, named U through Z from the oldest to the youngest. Ages of these six events are constrained at 40000-36300BC, 35400-24800BC, 9500BC-500AD, 390-720AD, 1120-1620AD and 1750AD-present. The Ganhaizi trench revealed three paleoearthquakes, named GHZ-E1 to GHZ-E3 from the oldest to the youngest. Ages of the three events are constrained at 3300BC-400AD, 770-1120AD, 1460AD-present. The Dafendi trench revealed three paleoearthquakes, named E1 to E3 from the oldest to the youngest, and their ages are constrained at 22300-19600BC, 18820-18400BC, and 18250-present. Caohaizi and Ganhaizi trenches are excavated on the western branch of the Xiaojiang Fault, the distance between them is 400m. We constrained four late Holocene paleoearthquakes with progressive constraining method, which are respectively at 500-720AD, 770-1120AD, AD 1460-1620 and 1833AD, with an average recurrence interval of 370~440a. Large earthquake recurrence in the late Holocene is less than the recurrence interval of~900a as proposed in the previous studies. Thus, the seismic hazard on the Xiaojiang Fault should be reevaluated. We excavated a large trench at Dafendi, about 30km away south of Caohaizi trench. Combining with previous paleoseismological research, it is found that the western branch of Xiaojiang Fault was likely to be dominated by segmented rupturing in the period from late of Late Pleistocene to early and middle Holocene, while it was characterized by large earthquakes clustering and whole segment rupturing since late Holocene.     

ANALYSIS OF THE CONFIDENCE INTERVAL OF THE COMPOSITE FAULT PLANE SOLUTION OBTAINED FROM THE GRID SEARCH METHOD: AN EXAMPLE OF SOUTHERN JIANGXI PROVINCE

In order to quantitatively analyze the reliability of the composite fault plane solution of small earthquakes, the Bootstrap sampling technique is introduced into the grid search method, and the ideas and methods for calculating the confidence interval from the grid search method are proposed initially. There are two sample sets that can represent the characteristics of the composite fault plane solution. One sample set is the optional solutions obtained by the grid search method and the other is obtained by the Bootstrap sampling technique. Then, we calculate the confidence intervals of the two sample sets (P, B and T axis). The research results of tectonic stress field in southern Jiangxi Province are relatively few. In view of such situation, we use the focal mechanism solutions of small earthquakes to calculate and analyze the composite fault plane solution and the confidence interval. This study shows that the confidence interval of the principal stress axis can be obtained well by both of the sample methods. The reliability of the results and the confidence range of the principal stress axis can be better represented by the confidence intervals. The middle principal stress in southern Jiangxi Province is nearly vertical, and the maximum and minimum principal stresses are nearly horizontal. The direction of maximum principal stress is NWW-SEE and that of the minimum principal stress is NNE-SSW. And, the area is in a strike-slip stress regime. The results are consistent with previous studies, and the stress directions obtained by previous researchers are within the confidence interval calculated by this paper.     

海洋磁力测量测线布设间距的选取

基于海洋磁力测量特点,在对布设测线方向研究的基础上,对海洋磁力测量中布设测线间距的选取进行了研究,提出了选取布设测线间距的原则,给出了几种选取测线间距的方法,并对其可行性进行了验证。     

改进的灰色模型在建筑物沉降预测中的应用

介绍灰色非等间距GM(1,1)模型的建立及其精度评定方法,着重探讨模型精度的主要影响因素,并从模型背景值的构造以及初值选取两个方面对灰色非等间距GM(1,1)模型进行改进,结合高层建筑沉降监测实例进行预测结果分析,结果表明,改进后的灰色模型具有较高的精度,在沉降预测中具有较高的应用价值。     

Geological characteristics and co-exploration and co-production methods of Upper Permian Longtan coal measure gas in Yangmeishu Syncline,Western Guizhou Province,China

Coal measure gas (also known as coal-bearing unconventional gas) is the key field and development direction of unconventional natural gas in recent years. The exploration and evaluation of coal measure gas (coalbed methane, coal shale gas and coal measure tight sandstone gas) from single coalbed methane has greatly expanded the field and space of resource evaluation, which is of positive significance for realizing the comprehensive utilization of coal resources, maximizing the benefits and promoting the innovation of oil and gas geological theory and technological advances in exploration and development. For the first time, in Yangmeishu Syncline of Western Guizhou Province, the public welfare coalbed methane geological survey project of China Geological Survey has been carried out a systematic geological survey of coal measure gas for the Upper Permian Longtan Formation, identified the geological conditions of coal measure gas and found high quality resources. The total geological resource quantity of coalbed methane and coal shale gas is 51.423×10⁹ m³ and the geological resource abundance is up to 566×10⁹ m³/km². In this area, the coal measures are characterized by many layers of minable coal seams, large total thickness, thin to the medium thickness of the single layer, good gas-bearing property of coal seams and coal measure mudstone and sandstone, good reservoir physical property and high-pressure coefficient. According to the principle of combination of high quality and similarity of key parameters of the coal reservoir, the most favorable intervals are No.5⁻², No.7 and No.13⁻² coal seam in Well YMC1. And the pilot tests are carried out on coal seams and roof silty mudstone, such as staged perforation, increasing hydraulic fracturing scale and “three gas” production. The high and stable industrial gas flow with a daily gas output of more than 4000 m³ has been obtained, which has realized the breakthrough in the geological survey of coal measure gas in Southwest China. Based on the above investigation results, the geological characteristics of coal measure gas in the multi-thin-coal-seam-developed area and the co-exploration and co-production methods, such as the optimization method of favorable intervals, the high-efficiency fracturing and reservoir reconstruction method of coal measures, and the “three gas” drainage and production system, are systematically summarized in this paper. It will provide a reference for efficient exploration and development of coal measure gas in similar geological conditions in China.     

改进不等时距权重的灰色残差组合修正模型及其应用

为提高传统不等时距灰色模型(TUTGM)的预测精度,提出了一种改进不等时距权重的灰色残差组合修正模型(IUTWGMRCC)。首先在传统不等时距灰色模型中引入时距权重分配系数,按照累加生成和累减还原过程的生成序列不同,构建了4种不同的预测模型,并依据相似度准则确定最优拟合序列和预测值;然后采用正弦函数和谐波变化生成的周期序列函数修正残差序列,进一步提高模型的预测精度;最后对建筑物3个观测点的沉降量进行预测。结果表明,累减还原过程引入不等时距权重的灰色模型预测精度最高,经残差组合修正后,预测结果的后验差比分别为0.04、0.11和0.05,精度等级为1级。     

北海市沿岸风暴潮特征研究

根据1965—2009年间影响北海市沿岸的热带气旋资料和风暴增水资料,进行统计分析北海市沿岸的风暴潮特征。结果表明:北海市沿岸平均每年发生风暴增水2—3次,其中较大以上强度的风暴增水每年0.87次,严重以上强度的风暴增水每3年有一次;北海市沿岸每年4—11月均有可能发生风暴增水,且集中在7—10月,尤以9月最多。影响北海市沿岸的热带气旋主要以西北行路径为主,且多是穿过雷州半岛或海南岛后在越南沿海登陆,此种情况下,风暴增水曲线表现为周期性波动。另外,本文还采用Pearson-Ⅲ分布和Gumbel分布来估算风暴增水频度,得出北海市沿岸不同重现期的高潮位值。     

磁县—大名断裂带西段晚更新世以来活动性研究

1830年河北磁县M7^1/2地震发生于磁县—大名断裂带西段, 该断裂地震破裂和活动性的研究受到地震研究者关注。前人研究着眼于1830年磁县大地震的地表破裂, 本文的研究重点是磁县—大名断裂带西段晚更新世以来的断层活动性。应用卫片、 航片解译和野外地震地质调查等方法开展研究, 重要地点进行探槽开挖或野外地质剖面剥落以及采样测年, 确定了断层各段落破裂事件的发生年代。该断裂西段分为3个断层段落: F₂为磁县—峰峰段落, F₃为东田井村—陶泉乡段落, F₄为韩家沟村—甘泉村段落。F₂断层段大部分隐伏, 为早中更新世断层。F₃断层段东端在东田井村南断错距今22 ka地层, 为晚更新世活动断层; F₃断层段在鼓山南山村一带为全新世断层, 从张家楼村到陶泉乡为推测全新世活动断层。F₄断层段为全新世断层。F₄断层段全部位于基岩山区, 可见多处基岩断面、 地震沟槽及断层眉脊等断层破裂; 一些破裂面发育地衣丽石黄衣[Xanthoria elegans (Link.) Th. Fr.], 使用地衣测年方法确定这些破裂面为1830年磁县大地震地表地震遗迹。磁县—大名断裂带终止于F₄西端。综合分析断裂带各个分段的破裂事件, 得到磁县—大名断裂带西段活动事件时空分布, 估计磁县—大名断裂带西段的晚更新世地震复发周期在6000年左右。     

惠州断层及其邻区地震危险性评价

惠州断层长约20 km,宽约5 km,产状135°—150°/NE∠65°—75°,在断层露头处可见复合断层角砾岩,这反映出该断层曾发生过多次运动.为研究该断层最新活动时代及地震危险性,得到的现今惠州断层垂直形变图显示,该区明显受区域活动构造所控制,垂直形变幅度相对较小,无明显的高速度梯度带;地壳水平运动状态测点的运动...