长江口海域新生代地层与断裂活动性初探   总被引：7，自引：1，他引：7  

火恩杰  章振铨  刘昌森  王锋 《中国地震》2003,19(3):206-216

长江口海域通过浅层人工地震勘察查明，新生代地层可分为5个地震层。分别为第四系、上新统、中新统上段、中新统下段及始新统。第三纪地层自东北向西南依次超覆、减薄尖灭，上部被第四纪地层不整合覆盖。沉积基底主要由晚侏罗世火山岩系及燕山晚期酸性小岩体构成，未发现早第三纪及晚白垩世断陷盆地。断裂构造很发育，按展布方向大体可归为北东、北西及近东西向3组，皆为正断层。前两者数量多、延伸长、断距大，与同区的航磁异常构架吻合。北东向断裂分段明显，西南段为第四纪断裂，中段为晚第三纪断裂，东北段为早第三纪断裂；而北西向断裂分段不很清晰。两者的垂直位移速率平均在0．015mm/a。本文对该海域有关的几个地质问题进行了讨论。  相似文献   

河流深槽沉积体与油气的关系——以辽河坳陷大25井区为例     

陈振岩  李军生  闫火  张戈  祝丽玲  陈峰  季东民 《沉积学报》1996,(3)

河流深槽沉积体是河流沉积的一种特殊沉积体。辽河坳陷第三纪断裂活动强烈，火山岩广泛分布，形成了独特的地貌条件，具备形成河流深槽沉积体的地质条件。本文以辽河坳陷东部凹陷大２５井区为例，对河流深槽沉积体的成因及特征进行探讨，证实了大２５井区巨厚砂砾岩沉积是河流在火山岩古地形的限制下发生急转弯，在其变曲河段的深槽中沉积的深槽沉积体。该沉积体中发育良好的储集空间，有利于油气储集。该类储集体的发现，丰富了辽河坳陷的储层类型，为油气勘探提供了新的领域。  相似文献   

Attenuation relations of ground motion for rock and soil sites in eastern United States     

Howard Hwang  Jun-Rong Huo 《Soil Dynamics and Earthquake Engineering》1997,16(6):363-372

This paper presents the attenuation relations of peak ground acceleration and spectral accelerations for rock and soil sites in the central and eastern United States (CEUS). For the bedrock site condition, 56 pairs of moment magnitude M and epicentral distance R are used to simulate ground motion, and for each pair of M and R, 550 samples of ground motion parameters are generated using a seismological model together with random vibration theory and distribution of extreme values. From the regression analyses of these data, the attenuation relations of ground motion parameters for the bedrock site are established. With the aid of appropriate site coefficients, these attenuation relations are modified for the site categories specified in the 1994 NEHRP Provisions. These attenuation relations are appropriate for the assessment of seismic hazards at far-field rock and soil sites in the CEUS.  相似文献   

The characteristics of Quaternary activity of faults in the sea area near the Yangtze River mouth     

章振铨  火恩杰  刘昌森  王锋 《地震学报(英文版)》2004,17(4):473-479

Introduction As far as the frequency and magnitude are concerned, the earthquakes in the sea area to the east of Shanghai are far more strong than in land area with the largest one in the sea area near the Yangtze River mouth being MS=436, while in land, only MS=434 occurred on Sept. 1, 1624. As a moderately strong earthquake active area, the sea area near the Yangtze River mouth, may cause a potential risk to Shanghai. In 1971 and 1996, earthquakes with MS=5~6 occurred in this area. Geo…  相似文献   

Preliminary Study on Cenozoic Group and Fault Activity in the Sea Area Near the Yangtze River Mouth   总被引：2，自引：0，他引：2  

Huo Enjie 《中国地震研究》2004,18(1):13-26

By shallow seismic prospecting, the Cenozoic Group in the sea area near the Yangtze Rver Mouth can be divided into five seismic sequences. They correspond to the Quaternary,Pliocene, Upper Miocene, Lower Miocene and Eocene respectively. The Quaternary System covers all the detecting area. The Tertiary System overlaps and thins out from NE to SW. The sedimentary basement mainly consists of volcanic rock (J3) and acidic rock (r35). Paleogene or Late Cretaceous basins are not found there. The faults that have been detected are all normal faults. They can be divided into three groups (NE, NW, near EW) by their trend. The NE and NW-trending faults are predominant, and agree with aeromagnetic anomaly. Their length and displacement are larger than that of the EW-trending faults. The activity of the NEtrending faults is different in different segments. The SW segment is a Quaternary fault, the middle segment is a Neogene fault, The NE is Paleogene. But the segment of the NW-trending fault is not obvious. The average vertical displacement rate is about 0.015mm/a.  相似文献   

A nonstationary extreme value distribution for analysing the cessation of karst spring discharge          下载免费PDF全文

Yan Liu  Yonghong Hao  Yonghui Fan  Tongke Wang  Xueli Huo  Youcun Liu  Tian‐Chyi J. Yeh 《水文研究》2014,28(20):5251-5258

The effects of climate change and population growth in recent decades are leading us to consider their combined and potentially extreme consequences, particularly regarding hydrological processes, which can be modeled using a generalized extreme value (GEV) distribution. Most of the GEV models were based on a stationary assumption for hydrological processes, in contrast to the nonstationary reality due to climate change and human activities. In this paper, we present the nonstationary generalized extreme value (NSGEV) distribution and use it to investigate the risk of Niangziguan Springs discharge decreasing to zero. Rather than assuming the location, scale, and shape parameters to be constant as one might do for a stationary GEV distribution analysis, the NSGEV approach can reflect the dynamic processes by defining the GEV parameters as functions of time. Because most of the GEV model is designed to evaluate maxima (e.g. flooding, represented by positive numbers), and spring discharge cessation is a ?minima’, we deduced an NSGEV model for minima by applying opposite numbers, i.e. negative instead of positive numbers. The results of the model application to Niangziguan Springs showed that the probability of zero discharge at Niangziguan Springs will be 1/80 in 2025, and 1/10 in 2030. After 2025, the rate of decrease in spring discharge will accelerate, and the probability that Niangziguan Springs will cease flowing will dramatically increase. The NSGEV model is a robust method for analysing karst spring discharge. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

基于Fisher判别的南方双季稻低温灾害等级预警   总被引：4，自引：3，他引：1       下载免费PDF全文

吴立  霍治国  杨建莹  肖晶晶  张蕾  于彩霞  张桂香 《应用气象学报》2016,27(4):396-406

为了建立南方双季稻低温灾害综合预测预警技术体系, 基于南方双季稻种植区1961—2010年708个气象站的逐日气象资料、水稻生育期资料和低温灾害发生的气象行业标准,采用Fisher判别分析法、因子膨化法、相关性分析法,利用SPSS软件构建早稻春季低温灾害高风险区 (Ⅰ区) 未来10 d、晚稻寒露风高风险区 (Ⅰ区)、主灾区 (Ⅱ区) 未来5 d的低温灾害发生等级逐日滚动预警模型。其中,1961—2009年资料用于模型构建和回代检验,2010年资料用于模型的外延预测。结果表明:早稻、晚粳稻、晚籼稻Ⅰ区平均外延预测基本一致准确率分别达到90.5%,74.2%,80.3%,晚粳稻、晚籼稻Ⅱ区平均外延预测基本一致准确率分别为89.4%和80.3%。构建的南方双季稻低温灾害逐日滚动预警模型的外延预测基本一致准确率多超过80%,等级预测检验误差总体上在1个等级以内,模型评价效果较好。  相似文献   

Growth performance of larval and juvenile manila clam (<Emphasis Type="Italic">Ruditapes philippinarum</Emphasis>) from divergently selected individuals of a full-sib family     

Zhongming Huo  Xiaotong Li  Qian Sun  Yongren Li  Xuekai Zhang  Xiwu Yan  Feng Yang 《中国海洋大学学报(英文版)》2016,15(6):1046-1050

In this study, the method of divergent selection was employed to test the larval and juvenile growth performance within a full-sib family of Manila clam Ruditapes philippinarum. The 10% largest and 10% smallest clam individuals (on the basis of shell length) of a full-sib family were selected as parents for the fast and slow growing lines, respectively. The difference in shell length was significant among the three lines (fast, control, and slow) tested. The sequence of shell length were fast line > control line > slow line. The responses to selection, realized heritability, and genetic gain were 0.06%–0.81%, 0.04%–0.47% and 0.58%–18.89% in the fast direction, respectively; and were 0.14%–1.27%, 0.08%–0.73%, and 0.31%–49.03% in the slow direction, respectively. The results suggested that there was a large portion of additive genetic variance affecting the growth in the full-sib family. Selection in the fast direction within the full-sib family would greatly improve the growth of R. philippinarum.  相似文献   

Impacts of agricultural water saving practice on regional groundwater and water consumption in an arid region with shallow groundwater   总被引：1，自引：0，他引：1  

Hang Chen  Zhongyi Liu  Zailin Huo  Zhongyi Qu  Yuhong Xia  Alexander Fernald 《Environmental Earth Sciences》2016,75(16):1204

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Dynamical evolution properties of debris flows controlled by different mesh-sized flexible net barriers     

Miao Huo  Jia-wen Zhou  Xing-guo Yang  Hong-wei Zhou 《Arabian Journal of Geosciences》2018,11(16):465

Because the flexible net barrier is a gradually developed open-type debris-flow counter-measure, there are still uncertainties in its design criterion. By using several small-scale experimental flume model tests, the dynamical evolution properties of debris flows controlled by large and small mesh-sized (equal to D₉₀ and D₅₀, respectively) flexible net barriers are studied, including the debris flow behaviors, segregation, and permeability of sediments, as well as the energy absorption rates and potential overtopping occurring when debris flows impact the small mesh-sized one. Experimental results reveal that (a) two sediment deposition patterns are observed depending on variations in debris flow textures and mesh sizes; (b) the aggregation against flexible net barriers is dominated by flow dynamics; (c) the segregation and permeable functions of the barrier are determined by the mesh size, concentration, and flow dynamics; and (d) the smaller mesh-sized flexible net barrier tends to be more efficient in restraining more turbulent debris flows and can absorb greater rate of kinematic energy, and finally, the great kinematic energy dissipation that occurs when secondary debris flows interact with the post-deposits in front of the small mesh-sized flexible net barrier is believed to cause the failure of overtopping phenomenon. The mesh size is concluded to be the decisive parameter that should be associated with debris flow textures to design the control functions of flexible net barriers.  相似文献