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1.
Seismic images of a collision zone offshore NW Sabah/Borneo 总被引：2，自引：0，他引：2
Dieter Franke Udo Barckhausen Ingo Heyde Mark Tingay Nordin Ramli 《Marine and Petroleum Geology》2008,25(7):606-624
Multichannel reflection seismic data from the southern South China Sea, refraction and gravity modelling were used to investigate the compressional sedimentary structures of the collision-prone continental margin off NW Borneo. An elongated imbricate deepwater fan, the toe Thrust Zone bounds the Northwest Borneo Trough to the southeast. The faults separating the individual imbricates cut through post-Early Miocene sediments and curve down to a carbonate platform at the top of the subsiding continental Dangerous Grounds platform that forms the major detachment surface. The age of deformation migrates outward toward the front of the wedge. We propose crustal shortening mechanisms as the main reason for the formation of the imbricate fan. At the location of the in the past defined Lower Tertiary Thrust Sheet tectonostratigraphic province a high velocity body was found but with a much smaller extend than the previously defined structure. The high velocity structure may be interpreted either as carbonates that limit the transfer of seismic energy into the sedimentary layers beneath or as Paleogene Crocker sediments dissected by remnants of a proto-South China Sea oceanic crust that were overthrust onto a southward migrating attenuated continental block of the Dangerous Grounds during plate convergence. 相似文献
2.
遥感影像相对辐射校正方法及适用性研究 总被引：2，自引：1，他引：1
遥感影像相对辐射校正是一项基础的数据预处理工作,用于去除影像整体的辐射不均匀性、条带噪声、坏线等辐射问题,经过30多年的发展,已形成几十种不同的相对辐射校正方法和算法。面对种类众多的相对辐射校正方法,它们之间的区别和关联是什么,每种方法的特点是什么,如何选择合适的校正方法,是3个亟需解决的问题。围绕这3个问题,第一,本文以相对辐射校正系数获取的不同方式为原则,将现有的相对辐射校正方法分为3大类:定标法、统计法和综合法,使该分类体系能够反映各类校正方法的区别和关联。第二,在新的分类体系下,给出了定标法、统计法、综合法的数学模型表达,详细介绍了3类方法包含的每种具体的校正方法和算法,比较分析了每种方法的基本思想、原理和优缺点。第三,从影像辐射不均匀特征、影像几何特征、传感器定标、影像综合特征4个方面,对各种校正方法的适用性进行综合分析,给出了科学合理地选择相对辐射校正方法的建议,同时结合具体应用实例进行了实验验证。最后,分析了相对辐射校正研究的发展趋势和存在的问题,有效信息和噪声的计算机判定准则、相对辐射校正效果的评价体系、相对辐射校正对于后续的绝对辐射校正结果的影响是下一步需要深入研究的问题。 相似文献
3.
利用浙江省2004~2013年3~8月Micaps（气象信息综合分析处理系统）地面填图数据和T-logP数据研究杭州、衢州和台州三市的阵雨和雷雨个例,同时选取能表征雷雨并能区分阵雨与雷雨的气象预报因子:对流有效位能、850 hPa与500 hPa的温差、K指数、地面2 m温度,用临近探空的分析方法和决策树的分类方法初步建立了一个适用于浙江省春夏季降水性质分类指标。利用欧洲中心（ECMWF）细网格预报资料,对历史样本和2016年春、夏季分别作了检验。结果表明:除去有降水预报误差个例后,指标TS（Threat Score）评分超过0.53,雷雨阵雨综合命中率达到71%,空报率阵雨（10%）小于雷雨（43%）,在不同地区和季节稍有区别;同时对浙江省2016年春夏两次典型大范围阵雨雷雨过程进行预报,效果很好。此方法不仅可以依据预报数据在短期内做出精细化降水性质分类预报,在中长期预报上也有表现力。 相似文献
4.
CHEN Yini LI Jun WANG Zhenjie ZHAO Mengqi YU Tiehong LI Danning YU Junyi WANG Weitao 《中国地震研究》2020,34(3):328-342
The phase identification and travel time picking are critical for seismic tomography, yet it will be challenging when the numbers of stations and earthquakes are huge. We here present a method to quickly obtain P and S travel times of pre-determined earthquakes from mobile dense array with the aid from long term phase records from co-located permanent stations. The records for 1 768 M ≥ 2.0 events from 2011 to 2013 recorded by 350 ChinArray stations deployed in Yunnan Province are processed with an improved AR-AIC method utilizing cumulative envelope and rectilinearity. The reference arrivals are predicted based on phase records from 88 permanent stations with similar spatial coverage, which are further refined with AR-AIC. Totally, 718 573 P picks and 512 035 S picks are obtained from mobile stations, which are 28 and 22 times of those from permanent stations, respectively. By comparing the automatic picks with manual picks from 88 permanent stations, for M ≥ 3.0 events, 81.5% of the P-pick errors are smaller than 0.5 second and 70.5% of S-pick errors are smaller than 1 second. For events with a lower magnitude, 76.5% P-pick errors fall into 0.5 second and 69.5% S-pick errors are smaller than 1 second. Moreover, the Pn and Sn phases are easily discriminated from directly P/S, indicating the necessity of combining traditional auto picking and integrating machine learning method. 相似文献
5.
Trenton T Cladouhos Susan Petty Yini Nordin Michael Moore Kyla Grasso Matt Uddenberg Michael W Swyer 《地下水科学与工程》2014,2(3):1-7
The Newberry Volcano EGS Demonstration in central Oregon tests recent technological advances designed to reduce the cost of power generated by EGS in a hot, dry well (NWG 55-29) drilled in 2008. An EGS reservoir was created by injecting large volumes of cold water, causing existing fractures to slip in shear (known as hydroshearing) generating the seismic waves that can be used to map fracture location and size. At the Newberry Demonstration the final injectivity ranged between 1.4 and 1.7 L/s/MPa a ~6x improvement over the initial injectivity of the well. The injectivity improvement and seismic analysis indicate that previously impermeable fractures were enhanced during the NWG 55-29 stimulation. 相似文献
6.
Early Cretaceous Palynological Assemblages of the Shuangliao Fault Depression, Songliao Basin and their Geological Implications 总被引：2，自引：1，他引：1
The pollen and spores found in the Early Cretaceous strata of two cores from the Shuangliao Fault Depression were studied systematically, and two palynological assemblages have been recognized. Assemblage Ⅰ from the Yingcheng Formation is named Paleoconiferus-Pinuspollenites; the assemblage is characterized by an extremely high content of Paleoconifer pollen. Assemblage Ⅱ from Member 1 of the Denglouku Formation is named Cicatricosisporites-Cyathidites-Pinuspollenites; the assemblage is characterized by the abundant presence of Laevigati spores, but less Paleoconifer pollen. According to the palynological data and zircon U-Pb dating, the geological age of the Yingcheng Formation is thought to be Aptian-Albian, and that of the Denglouku Formation is thought to be Early Albian. On the basis of the composition of each assemblage, we can infer that during the depositional period of the Yingcheng Formation, the paleovegetation was mainly conifer forest, the paleoclimate was consistent with the temperate climate of today, and the paleoenvironment was humid feature. During the depositional period of Member 1 of the Denglouku Formation, the paleovegetation was mainly conifer forest and shrubs, the paleoclimate was consistent with the subtropical climate of today, and the paleoenvironment was humid. The results significantly improve our understanding of the stratigraphy in the Shuangliao Fault Depression, provide biostratigraphic evidence for the division and correlation of Early Cretaceous strata in the Shuangliao Fault Depression, and provide new data for analyzing paleovegetation and paleoclimate in the Songliao Basin. 相似文献
7.
The apparent ionization constants for silicic acid, k1 and k2, and the ionic product of water, kw, have been determined in 0.05, 0.1, 0.2, 0.4 and 2.0 M Na(CI) media at 25°C. The medium dependence of these constants was found to fit equations of the form where K1 is the ionization constant in pure water, αi and bi are parameters of which bi has been adjusted to present data. The following results were obtained (αi, bi): pK1 = 9.84, (1.022, ?0.11); pK2 = 13.43, (2.044, ?0.20); and pKw = 14.01 (1.022, ?0.22). ki values are collected in Tables I and II. Attempts have been made to explain the medium dependence of k1 and k2 with weak sodium silicate complexing according to the equilibria giving k11 = 0.37M?1 and k21= 3.0M?1. However, these weak interactions cannot be interpreted unambiguously from potentiometric data at different 1-levels. Probably the medium dependence could equally well be expressed by variations in the activity coefficients.The measurements were performed as potentiometric titrations using a hydrogen electrode. The average number of OH- reacted per Si(OH)4, Z, has been varied within the limits 0 ? Z ? 1.1 and B1, the total concentration of Si(OH)4, between 0.001 M and 0.008 M. k1 was evaluated from experimental data with B ? 0.003 M, and k2 with B ? 0.008 M and Z ? 0.95. 相似文献
8.
Fred Saunders Salim M. Mohammed Narriman Jiddawi Karolina Nordin Bengt Lundèn Sara Sjöling 《Ocean & Coastal Management》2010,53(4):150-160
Coastal areas in East Africa are experiencing rapid economic, resource management, demographic and technological shifts. In response diverse Community-based Natural Resource Management (CBNRM) applications have been embraced to provide mutual conservation and use benefits. These initiatives have met with mixed success in practice. Reflecting on the limitations of past research using common pool resources theory theory to study CBNRM we use insights from actor oriented theory combined with satellite image analysis to describe and discuss the forces dynamically influencing institutional and mangrove forest cover change at Kisakasaka, Zanzibar focussing on the formal CBNRM project period between 1996 and 2001, but also considering the period before and after this. We examine the shifting social relations that affected the performance and viability of the formal CBNRM arrangements. An integrated approach was taken to the presentation and discussion of results where it was possible to enrich and expand explanations of socio-environmental change, which was driven by a lack of government support, the undermining effects of party political divisions, and the lack of institutional adaptive capacity. We conclude that this was a useful approach to explain CBNRM intervention events at Kisakasaka. 相似文献
9.
在大中城市周边建设地震台阵,可解决城市内地震监测台站建设不便和背景噪声高等问题,增强人口密集区的地震监测能力。杭州湾地区沉积层较厚,建设基岩地震台站不够现实,为适应长三角区域的一体化发展,增强该区地震和非天然地震的监测能力,在浙江临安建设地震台阵。使用GL-PS60一体化宽频带地震计进行测点勘选工作,利用Welch平均周期法,对9个子台进行背景噪声功率谱估计。结果发现,背景噪声功率谱相关性较好,且与全球噪声模型一致性较好。在台阵勘选过程中,于2017年4月12日和13日分别记录到临安4.2级地震及菲律宾远震事件,波形清晰,表明初选台址效果较好,符合地震台阵建设要求。 相似文献
10.
DEM及数字地形分析的精度无疑受到包括高程数据空间内插方法在内的多种因素的影响,本研究利用模拟高斯曲面为基准数据,通过四种不同插值方法结果的对比,分析说明每种插值方法在某一标度范围内插值精度的优劣,从而在应用中针对不同条件采用相应优选的插值方法.在此基础上,对于四种插值方法生成相应的坡度、坡向值,通过与真值的比较探讨插值方法对用DEM提取坡度、坡向的影响.实验结果确定了不同内插方法对坡度和坡向因子提取精度的大小,发现在坡度方面,SPLINE方法内插出来的坡度最精确,其他依次为KRIGING,IDW,TIN;在坡向方面,SPLINE内插出来的坡向最接近真值,是最精确的插值方法,其他依次为KRIGING,TIN,IDW.以上结果为空间插值方法的选择提供了参考. 相似文献