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江苏地区莫氏面深度图是结合人工测深资料,利用压缩质面法反演重力资料求取莫氏界面深度,而后使用计算机绘制成图的。由于本区人工测深资料和地质资料都比较丰富。为求取莫氏界面深度提供了约束条件与旁证材料,加之适当地加密了布格异常的采样点以及计算点分布十分均匀,因而计算误差较小,成图精度也高,并与人工测深资料所得出的结果非常一致。 相似文献
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大地电场岩性测深原理及方法技术的探讨 总被引:10,自引:0,他引:10
本文主要探讨大地电场岩性测深技术的基本原理及参数意义,然后介绍测深资料的解释及评价方法和几个应用实例。指出岩性测深技术的理论基础应在实践中研究,总结和发展。 相似文献
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回顾了我国80年代中期以来大地电磁测深工作的进展,包括资料采集、数据处理和反演解释着重介绍了大地电磁测深法在石油、天然气构造普查勘探以及地壳和上地慢探测方面应用的情况. 相似文献
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大地电磁测深资料数据采集过程中,由于温度、湿度等对仪器的影响或GPS搜星不正常,采集到的数据有时会出现时间序列跳帧或缺失现象.针对这一问题,本文将基于无激励AR(p)模型预测数据的原理引入大地电磁测深数据处理中.根据已知序列确定AR(p)模型阶数以及模型参数,建立正确的预测模型对缺失数据进行预测,并对比经过预测后的数据与实际样本数据的频谱,表明AR(p)预测模型可以解决原始资料的不连续性问题,提高了大地电磁测深野外资料的利用率. 相似文献
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针对南黄海盆地深层地震地质条件差,地震波受屏蔽,能量严重衰减,在海洋反射地震资料中很难识别反映中-古生界的反射地震波组,不能满足南黄海盆地前第三系油气资源前景评价的需要等问题,于2006年5月,开展了南黄海海域海底大地电磁测深试验,在盆地内五莲斜坡和胶州凹陷区布设了3个海底大地电磁测深点,取得了可靠的海底观测数据.本文详细阐述了海底大地电磁测深与常规大地电磁测深在数据处理方法上的差别,论述了海洋电磁噪声对海底大地电磁场观测的影响,提出了海底大地电磁场实测资料“水平姿态”校正、“方位”校正和“海洋电磁噪声”校正的方法.通过对试验观测资料的处理和反演,并结合地质、物性资料进行综合分析,结果表明在南黄海盆地海底以下深部还存留有古生代地层,这对于南黄海前第三系含油气前景的评价具有重要意义.试验结果也证明了海底大地电磁测深技术在研究古生代残留盆地方面的问题可以发挥相当好的作用. 相似文献
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Stephen E. L. Howell Jane Assini Kathy L. Young Anna Abnizova Chris Derksen 《水文研究》2012,26(23):3477-3488
Snowmelt onset and end date estimates are made from QuikSCAT scatterometer measurements in the Canadian High Arctic wetland of Polar Bear Pass (PBP) and the surrounding region of Bathurst Island, Nunavut. In situ data within PBP is used to validate QuikSCAT snowmelt onset/end date estimates. Results indicate that within PBP from 2000 to 2009, the mean snowmelt onset date was Year Day (YD) 162, the mean snowmelt end date was YD179, and the mean snowmelt duration was 17 days. More interannual variability was apparent in snowmelt end date and duration compared with onset, and only snowmelt end date was significantly correlated with mean June air temperature at ?0.78. Cooler air temperatures in 2004 contributed to a long snowmelt duration of 24 days, and the very short snowmelt duration in 2007 of just 11 days was caused by rapid and sustained increases in air temperature. For snowmelt end date and duration the mean spatial pattern revealed two centres of later snowmelt end date/longer snowmelt duration over Bathurst Island. They were separated by early snowmelt end date/short snowmelt duration in PBP. These patterns are in agreement with the spatial distribution of mean May to July air temperature over Bathurst Island and are likely influenced by the local‐scale topography of Bathurst Island. Given the correlation between air temperature and snowmelt end date, we might expect quicker snowmelt under increased warming. The latter process may have implications for the sustainability of the PBP wetland under a warmer climate. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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针对目前尚缺乏客观的流域梅雨划分指标的现状,本文依据最新的梅雨监测国家标准与NCEP/NCAR再分析资料,利用19862016年太湖流域水文年鉴逐日雨量整编资料,重新划分了太湖流域入/出梅日期,计算了梅雨特征量,构建了梅雨洪水指数(RFI),并对梅雨期超设计、超警戒洪水年的环流异常成因进行分析.研究表明:(1)新标准下太湖流域多年平均在6月17日入梅,7月11日出梅,梅雨期长度24 d,梅雨量266.8 mm;与历史序列相比,新标准确定的梅雨量一致率较高,其次是入梅时间和出梅时间.(2)雨日数和副高脊线北跳时间是影响入/出梅确定的两个重要因素,新标准将1992、2013年定为空梅,1986、1987、1989、1996、2005年历史入/出梅日期向后调整,1988、2007年出梅日期向前调整,更为合理地反映了梅雨的高温高湿气候特征,客观性较强.(3)梅雨量越大,雨强越大,太湖水位越高,流域越易涝;以梅雨洪水指数作为参考因子,考虑到影响太湖洪水形成的两个关键因子(梅雨期起涨水位、最大7 d降水量占梅雨量的比例),对入梅起涨水位异常偏高、因集中强降雨引起太湖洪水的指示意义较强.(4)高低纬环流配置关系密切,来自西太平洋经南海的偏南气流、印度洋经孟加拉湾的西南暖湿气流汇合后与来自北方的冷空气在太湖流域交汇,太湖流域垂直上升运动异常强烈,触发降雨层结不稳定能量释放,导致暴雨持续形成洪水. 相似文献
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《水文科学杂志》2013,58(2)
Abstract In ice forecasting, a key problem is the forecast of freeze-up and break-up dates. Ice-water mechanics and the principle of heat-exchange were mainly adopted in previous research. However, the mathematical models in these studies are complex and many parameters are required in relation to upstream and/or downstream gauging stations. Moreover, too many assumptions or simplifications for these parameters and constraints directly lead to low accuracy of the models and limitations as to their practical applications. This paper develops a fuzzy optimization neural network approach for the forecast of freeze-up date and break-up date. The Inner Mongolia reach lies in the top north of the Yellow River, China. Almost every year ice floods occur because of its special geographical location, hydrometeorological conditions and river course characteristics. Therefore, it is of particular importance for ice flood prevention to forecast freeze-up date and break-up date accurately. A case study in this region shows that the proposed methodology may allow obtaining useful results. 相似文献
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Dating phases of pedogenesis, soil carbonate deposition or even the burial of whole soil profiles using 14C is a valuable goal in archaeology and pedology, but one that has been consistently hampered by the presence of old carbon skewing the measurements to produce apparent dates older than the true formation date. Calcite produced by earthworms could be a useful alternative source of datable carbon. Since earthworms both inhabit and ingest soils with an old carbon content, however, the granules could yield a 14C date older than the date of their formation. In this study, by examining granules from two sites of known-age stratigraphy, we show that the radiocarbon date derived from the granules' calcite closely reflects their true formation date, opening up the possibility of using the granules either individually or as distributions of dates to understand soil processes and date sealed archaeological layers. 相似文献
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R.Lawrence Edwards F.W. Taylor G.J. Wasserburg 《Earth and Planetary Science Letters》1988,90(4):371-381
Mass spectrometric techniques have recently yielded significant increases in precision and sensitivity over previous methods for measuring230Th abundance in corals. To assess the accuracy of230Th ages, three corals from Vanuatu, whose ages were known from counting annual growth bands, were analyzed. For each sample, the date of growth determined by230Th analysis (A.D.1969 ± 3, 1932 ± 5,and1806 ± 5; 2σ uncertainties based on analytical error) was indistinguishable from the date determined by counting bands (A.D. 1971–1973, 1935–1937, and 1804–1810), indicating that the230Th dates are accurate.230Th dates were also determined for two adjacent emerged heads from Santo Is., Vanuatu, which were thought to have died when they were raised above sea level during coseismic uplift. The dates (A.D.1864 ± 4, 1866 ± 4) were the same, indicating that the heads died at the same time and consistent with the idea that they were killed by coseismic emergence around A.D. 1865. The difference between this date and the date of the only major historically documented earthquake that caused uplift (A.D. 1973,Ms = 7.5), suggests a seismic recurrence interval of108 ± 4y for Santo. Analogous emerged corals from Malekula Is., Vanuatu yielded230Th dates that were similar to each other (A.D.1729 ± 3, 1718 ± 5) and are inferred to have died during coseismic emergence around A.D. 1729. In conjunction with the date of the only large historically documented earthquake that caused uplift (A.D. 1965,Ms = 7.5), the recurrence interval for Malekula is236 ± 3y. If similar emerged corals can be found, this appraoch may be extended back in time and to other localities because it appears that such features can now be dated both accurately and precisely. 相似文献
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断层的活动时代是活动构造、古地震和新构造等研究中的重要内容 ,也是目前的难点所在。确定断层最新一次活动事件的年代通常有两种途径 :一是通过测定断层活动产物 (如断层泥、断层破碎物、崩积楔等 )的年龄来确定断层事件的年代 ;二是通过测定断层错动的最新地层及其上覆未错动的最老地层的年龄 ,来获得活动年代的上下限年龄。根据沿高丽营断层在房山坨里至永定河一带所观察到的活动断层的具体特征 ,分别采用了上述两种途径和相应的测年技术 ,给出了芦井、晓右营、辛开口和长辛店等地断层的最后一次活动的大致年代。高丽营断层至少有过 3次活动 ,分别发生在距今 2 70~ 36 0 ,130~ 140和 1.8~ 4 .2ka 相似文献
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中国地震局系统期刊编排质量分析 总被引:1,自引:0,他引:1
以中国地震局系统公开出版发行的25种学术类、综合类期刊为研究样本,对照有关文献工作的国家标准、规范,对这些期刊的开本、封面、条码、书脊、目次表、摘要、关键词、分类号、序号、量和单位、数字和日期、数学和物理公式、图、表、总目次和索引、项眉、作者简介、收稿日期、参考文献表、版权标识、印刷装帧等情况进行了统计分析,得出地震期刊编排质量大体符合国家标准,规范的结论,指出了存在的问题,提出了进一步加强地硅期进编排标准化、规范化工作的建议。 相似文献
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Rb-Sr whole-rock investigation of the Pedernal Hills, New Mexico, indicates a 1471 ± 97-m.y. date for the granites and 1364 ± 27-m.y. date for the schists and quartzite (country rocks) with initial87Sr/86Sr = 0.7060 ± 0.0040 and 0.7046 ± 0.0019, respectively. The schists and quartzites are older than the granites based on field and petrographic evidence. The open-system nature of these rocks during the cataclastic metamorphism which affected both the country rocks and the granites is responsible for the apparent younger date of the schists and quartzite, and the 1471 ± 97-m.y. date may be a minimum age for the granites. 相似文献
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本文用正演方法讨论的问题有:声波速度(或声波时差)在断层附近的异常;用声阻抗信息研究生油泥岩的性能;地层压力的估算方法及地层压力数值在研究古地应力场及地质构造中的应用. 相似文献