南黄海中部海底沉积物原位声速与物理性质相关关系   总被引：2，自引：1，他引：1  

阚光明  苏元峰  李官保  刘保华  孟祥梅 《海洋学报》2013,35(3):166-171

基于在南黄海中部获得的海底沉积物原位声速数据,分析讨论了原位声速与密度、含水量、孔隙比、孔隙度等沉积物物理性质参数的相关关系。通过回归分析建立了海底沉积物原位声速预测方程。结果表明,原位声速与上述物理参数之间具有良好的相关性,相关系数r均大于0.93。对比分析了原位声速预测方程与甲板声速预测方程的差异,两者最小相差15.8 m/s,最大相差31.3 m/s,平均差值约为22.6 m/s。将原位声速预测方程与其他研究者建立的声速预测方程进行了对比,结果表明不同声速预测方程存在明显差异,初步分析了存在差异的原因。  相似文献   

Sea Floor Sediment and Its Acouso-Physical Properties in the Southeast Open Sea Area of Hainan Island in China     

B. Lu  G. Li  Q. Liu  S. Huang  F. Zhang 《Marine Georesources & Geotechnology》2013,31(3):129-144

Acouso-physical properties of sea floor sediments in the southeast offshore sea area of Hainan Island on the northern continental shelf of the South China Sea are analyzed. In many cruises, conductivity-temperature-depth measurements of seawater, measurements of shallow stratum and side-scan sonar have been made. Acoustic parameters, basic sedimentary parameters, physical-mechanical parameters and ¹⁴C age, etc., have been measured. The sediment elastic parameters, including Young's modulus, bulk modulus, constrained modulus, rigidity modulus, Poisson's ratio, Lames constant, etc., have been calculated. Results show that the compression wave velocity of the seafloor sediment in the sea area ranges from 1474–1700 m/s, and there are high and low sound velocity sediment types in the different sea areas; the shear wave velocity is 150–600 m/s; at 100 kHz the sediment sound attenuation is 35–260 dB/m, the sediment density is 1.4–2.0 g/cm³; the sediment porosity is 42–88%. Sound field parameters and describing sound reciprocity between sea and seafloor are described.  相似文献   

Geotechnical Investigation of the Titanic Wreck Site     

Angus I. Best  William Powrie  Toby Hayward  Max Barton 《Marine Georesources & Geotechnology》2013,31(4):315-331

Abstract

Recent marine forensic investigations have largely unravelled the sequence of events concerning the sinking of the R.M.S. Titanic and its descent through nearly 3800 m of water to the seafloor on the morning of 15 April 1912. In particular, the velocity and attitude of the Titanic's bow section (at present lying upright, reasonably intact, and embedded by ～12 m at the prow) as it hit the bottom are of general interest to marine accident investigators. During the 1998 Titanic Science Expedition, a single sediment sample was retrieved from the seafloor (depth 20–30 cm) near the wreck by the deep water submersible, Nautile. Published geological studies suggest the seafloor in this area has remained largely undisturbed since 1912. Geotechnical analysis of the sediment sample reveals that the impact was probably a substantially undrained event and that the characteristic undrained shear strength of the sediment is ～25kPa within 10–16 m below the seafloor. A simple analytical model was used to calculate the embedment of a cuboid with dimensions and mass of the water-filled bow as a function of impact velocity, impact angle, and the undrained shear strength of the sediment. The results indicate the impossibility of a steep angle of impact and fast velocity. The most likely scenario is an impact velocity of 5–10 m/s at a fairly shallow angle (<40°), which corroborates the results of hydrodynamic investigations.  相似文献   

Assessment of Impact on Seafloor Features in INDEX Area     

Rahul Sharma 《Marine Georesources & Geotechnology》2013,31(3):237-250

Abstract

Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in pre-disturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions.  相似文献   

Sound Velocity of Seafloor Sediment and its Response under Axial Stress-Strain     

Bo Lu  Ganxian Li  Shaojian Huang 《Marine Georesources & Geotechnology》2013,31(3):190-200

The results of axial stress-strain measurements made from short columnar samples of seafloor shallow surface sediment in the southern South China Sea area indicate that there are three kinds of variations in the longitudinal wave sound velocity, which are related to such characteristics as physical-mechanical properties, grain contact status and grain structure and microstructure of the submarine shallow surface sediment. This study may make theoretical contributions to further understanding the reliability of various submarine sediments in the southern South China Sea as bearing interfaces and such scientific objectives as phonotelemetering and remote sensing of the engineering mechanical properties of seafloor sediment.  相似文献   

双探针型海底热流计的结构优化   总被引：1，自引：0，他引：1       下载免费PDF全文

杨小秋  施小斌  许鹤华  徐行  李官保  郭兴伟  罗贤虎 《地球物理学报》2009,52(5):1280-1288

本文在现有海底热流探针制作技术条件下,首先建立了脉冲式双探针海底测量单元的有限元数值模型,模拟获得多组参数下的温度-时间数据,作为“实测”数据,再用脉冲加热有限长线热源(PFLS)模型求解待测介质热导率及其相对误差上限(RE_λ-UL),并以RE_λ-UL最小为原则,对双探针热流计的结构进行优化.结果表明:(1)在不同探针脉冲强度(q)、温度测量误差(ΔT_m)和探针长度(L)组合下,都存在最佳探针间距(Best_r),使得RE_λ-UL降到最低;(2)随着q增大或ΔT_m减小,Best_r逐渐增大;(3)当q、ΔT_m及探针半径(a)都给定时,Best_r与探针长度(L)呈线性正相关;(4)当a=1.0 mm,且q、ΔT_m分别取为628.0~1100.0 J·m^-1、0.5~1.0 mK,若L在20.0~42.0 mm之间时,则Best_r在18.0~30.0 mm之间,此时介质热导率相对误差上限可控制在5.5%以内,同时测量温度可在6 min内达到最大值,即脉冲加热开始后,温度测量只需约7 min,便可满足介质热导率的求解,这比目前常用的Lister型热流计所需海底测量时间缩短8 min左右.  相似文献   

趋势面分析在水深测量数据处理中的应用   总被引：8，自引：1，他引：7  

胡光海  周兴华 《测绘工程》2004,13(3):23-25

趋势面分析是用一个数学函数代表几何平面或曲面模拟事物的空间分布,以反映其分布的规律或趋势.利用趋势面分析法处理埕岛油田海区CB6C井区的水深数据,识别水深测量中出现的水深误差.  相似文献   

南海北康盆地热流分布特征及其构造控制因素探讨   总被引：1，自引：0，他引：1  

陈爱华  徐行  罗贤虎  廖开训  彭登 《地质学报》2017,91(8):1720-1728

热流是天然气水合物储量估算和油气资源评价的基础数据。南海实测热流数据虽然多,但分布不均。为深入认识北康盆地的热流特征,本文首先利用北康盆地获得的实测热流数据和前人研究成果,绘制了北康盆地热流分布图;根据热流和地温梯度变化特征,重点讨论了北康盆地热流异常区的成因机制,并根据区域地质构造背景,对北康盆地热流分布主要的控制因素进行了简要分析。数据统计结果表明:北康盆地热流变化范围为43.0~115.0mW/m~2,平均为76.8±21.7 mW/m~2;地温梯度变化范围为49.0~133.1℃/km,平均地温梯度为82.2±22.4℃/km。热流整体偏高,具有西高东低,南部高、东南部热流最低的热流特征,且在盆地西北部具有明显的热流异常。分析认为:(1)热流异常区中B区是由于海底高导层埋深影响,A区和C区是由海底流体渗漏区的地下水循环导致热流异常,推测A区为补给区,C区为排泄区;(2)北康盆地热流分布明显受构造作用的控制。西北部及南部受廷贾断裂控制,而东南部为古俯冲带及古洋陆过渡带,西高东低的热流分布特征还与盆地经历的3次快速沉降作用有关,但北康盆地拉张的构造背景引起整体热流值偏高。这对北康盆地油气和天然气水合物的研究均有重要意义。  相似文献   

基于DEM的山地总辐射模型及实现   总被引：15，自引：0，他引：15  

杨昕  汤国安  王雷 《地理与地理信息科学》2004,20(5):41-44

总辐射状况是决定山地气候的主导性因子。山区地形条件复杂,总辐射分布差异显著,为了便于研究山区总辐射的地域分布规律,该文建立了一种基于DEM模拟山区总辐射的方法,通过提取数字坡度模型、数字高度模型以及地形遮蔽度模型等信息,并采用多层面复合分析的方法,建立了山区直接辐射、散射辐射以及总辐射的数字模型。实验证明,太阳总辐射及其分量在山区中有很强的地域分布规律。该方法采用的DEM精度高,能够精细地反映太阳辐射的地区分布差异,为山地气候资源调查与利用、生态环境建设乃至精细农业的实施提供重要依据。  相似文献   

基于DEM的黄河流域天文辐射空间分布     

邱新法  曾燕  刘昌明  WU Xianfeng 《地理学报(英文版)》2004,14(1)

Based on the developed distributed model for calculating astronomical solar radiation (ASR), monthly ASR with a resolution of 1 km× 1 km for the rugged terrains of Yellow River Basin was calculated, with DEM data as the general characterization of terrain. This model gives an all-sided consideration on factors that influence the ASR. Results suggest that (1) Annual ASR has a progressive decrease trend from south to north; (2) the magnitude order of seasonal ASR is: summer＞spring＞autumn＞winter; (3) topographical factors have robust effect on the spatial distribution of ASR, particularly in winter when a lower sun elevation angle exists; (4) the ASR of slopes with a sunny exposure is generally 2 or 3 times that of slopes with a shading exposure and the extreme difference of ASR for different terrains is over 10 times in January; (5) the spatial differences of ASR are relatively small in summer when a higher sun elevation angle exists and the extremedifference of ASR for different terrains is only 16% in July; and (6) the sequence of topographical influence strength is: winter＞autumn＞spring＞summer.  相似文献