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1.
In the last few decades, seafloor imagery systems have drastically changed our vision of a mostly regular and depositional marine landscape, evidencing how erosive and mass-wasting processes are widespread in the marine environments, with particular reference to geologically-active areas. Most of the previous studies have focused on the characterization of these features, whereas a very few ones have tried to estimate what is the extent and order of magnitude of erosion rates in these areas. In this paper, we show several examples from some of the most geologically-active margins off Southern Italy aimed to a) quantify the spatial extent of such processes, b) better understand the role of submarine erosion in the morphogenesis of the coastal sector, and c) try to roughly estimate the order of magnitude of erosion rates in these areas. The results are impressive, with mass-wasting features widespread from coast down to −2600, affecting from the 52% up to 97% of the whole continental slope. Because of the narrow or totally lacking shelves in these areas, mass-wasting processes often occur close to the coast and match embayment of the coast, so indicating a key role in the morphogenesis of coastal sector, with significant implication on the related geohazard. Finally, based on a morphological approach integrated by available stratigraphic constraints we have roughly estimated average erosion rates in these areas, ranging from (at least) some mm/year to a few cm/year, i.e., some hundreds of meters up to kilometers eroded in each eustatic cycle. Despite the large uncertainties of these estimates as well as their spatial and temporal variability in response to regional and local factors, the obtained values are very high and they should be considered for future model of margin evolution, source-to-sink computation and marine/coastal geohazard assessment. 相似文献
2.
秦皇岛地区海岸侵蚀与淤积因素分析 总被引：7，自引：0，他引：7
近些年来，秦皇岛地区海岸侵蚀已成为一种严重的地质灾害。通过分析计算，本区地壳上升的速度量级很小，不会对海岸的侵刨造成显著的影响。海平面的升高，使区内一些稳定区及下降区的海岸侵蚀加强。尽管秦皇岛所处的渤海周围有许多特别是象黄河这样的高泥沙含量的河流，但其大部分泥沙只分布在沿岸地带。 相似文献
3.
中国砂质海岸分布特征与存在问题 总被引：10，自引：0，他引：10
中国东部砂质海岸分布范围广泛,地形发育多样,风沙灾害、海岸侵蚀等地质灾害问题多发,严重影响了沿海地区的社会经济发展。了解沙质海岸的分布特征,做好砂质海岸的研究防护工作,对促进海洋经济持续稳定的发展有着十分重要的作用。 相似文献
4.
M. Sanò J.A. Jiménez R. MedinaA. Stanica A. Sanchez-Arcilla I. Trumbic 《Ocean & Coastal Management》2011,54(12):943-950
Coastal erosion and storms represent a source of risk for settlements and infrastructure along the coast. At the same time, coastal natural assets, including landscape, are threatened by increasing development mainly driven by tourism. The Mediterranean coast is especially vulnerable to these processes, considering its high biological and cultural diversity. An additional challenge is represented by climate change, as it will force coastal communities to apply more or less drastic adaptation strategies. Coastal setbacks, used to protect coastal communities and infrastructure from storms and erosion, and to preserve coastal habitats and landscapes from degradation, is one of the main instruments suggested by the Protocol on Integrated Coastal Zone Management of the Barcelona Convention, entered into force on the 24 of March 2011. Its implementation has the potential to influence coastal policies in other regions, such as the neighbouring Black Sea.The CONSCIENCE project has formalized concepts and conducted specific studies to provide new tools for coastal erosion management practice. The objective of this paper is to present a synthesis of the research conducted into coastal setbacks for coastal erosion management and climate change adaptation. This is done by analysing the requirement of the Protocol, current processes and management practices in two case study areas (Costa Brava Bays in Spain and Danube Delta, in Romania) and the new challenges posed by climate change. 相似文献
5.
中国海岸侵蚀治理和海岸保护 总被引：5，自引：0，他引：5
加强海滩和海岸侵蚀的研究，组织建筑用砂资源的调查，进一步完善海洋环境保护法或制定海岸环境保护法以便制止不合理的采砂和保护沿岸单位和居民的合法权益，使出现环境问题后的赔偿有确定保证，防止人工海岩进一步扩大，发展偏僻海岸地区的发候旅游，让沿岩居民能从保护海岩中得到实际利益，以便使我国海岸侵蚀治理和海岸保护达到一个新水平。 相似文献
6.
辽东湾两侧砂质海岸侵蚀灾害与防治 总被引：9，自引：1，他引：9
自20世纪60年代至90年代，由于多种原因，辽东湾东西两侧的初始沙质海岸侵蚀范围逐年扩大，侵蚀不断加剧，给当人民的生产和生活带来严重危害。由多年监测资料发现，侵蚀严重的熊岳岸线以2～4m／a的速率而大幅度后退，特别严重的地区最大后退达10km；辽西绥中某些岸段平均每年后退1～2m。20世纪90年代后期，由于一些海域管理措施的出台和相应的海岸防护工程的建设，海岸侵蚀逐渐减弱。通过现场调查和多年监测，分析了辽东湾东西两侧砂质海岸侵蚀的特点，认为海岸组成物质松散与海岸动力作用强烈是本区现代海岸侵蚀的基本条件，人为活动是关键因素，并提出了海岸侵蚀灾害的防治对策。 相似文献
7.
海平面上升对中国沿海地区影响初析 总被引：2，自引：0，他引：2
近五十年来中国沿岸海平面变化总的呈上升趋势，年变率平均为１．４ｍｍ／ａ，中国沿岸地形复杂，未来海平面上升可能影响的主要脆弱区为黄河、长江和珠江三大三角洲和滨海平原，其可能受害区域估计达３５０００ｋｍ＾２。影响中国沿岸相对海平面上升的主要因素有：近代地壳垂直运动和地面沉降，台风和风暴潮，海岸侵蚀和海咸水入侵等。 相似文献
8.
Ａｍｏｄｅｌｏｆｐｒｏｆｉｌｅｅｖｏｌｕｔｉｏｎｏｎｗａｖｅ－ｄｏｍｉｎａｔｅｄｍｕｄｃｏａｓｔＺｈａｎｇＹｏｎｇ，ＹｕＺｈｉｙｉｎｇａｎｄＪｉｎＬｉｕ（ＲｅｃｅｉｖｅｄＪｕｌｙ２３，１９９６；ａｃｃｅｐｔｅｄＯｃｔｏｂｅｒ．．８，１９９６）Ａｂｓｔ... 相似文献
9.
河口岸滩侵蚀研究进展 总被引：4，自引：0，他引：4
系统了介绍了几十年来岸滩侵蚀的研究进展,认为大部分研究成果多是对岸滩侵蚀的机理和侵蚀过程的研究,主要采用定性的或者定性—半定量的研究方法,因为横向输砂的机理还不是很清楚,定量分析的数学模型研究较多但不成熟。在深入分析的基础之上,就今后岸滩侵蚀的研究工作进行了讨论,并提出了几点建议。 相似文献
10.
Ray-Yeng Yang Ying-Chih Wu Hwung-Hweng Hwung Jiing-Yih Liou Igor V. Shugan 《Ocean & Coastal Management》2010,53(9):552-561
The shoreline of Taiwan is approximately 1100 km long, composed of sandy beach, rocky coast, and reef coast. Almost half of the shoreline has been protected by seawalls, which play an important role for coastal protection and prevent people and infrastructure from coastal hazard. Besides, offshore breakwaters and groynes are also built in the serious erosion coastal shores. All these hard engineering structures made our coastal land safety to some extent at last fifty years. However, until now, the hard engineering structures applied for shore protection do not always work well on all the coasts around Taiwan. Some coastal areas still get eroded seriously with structures being damaged. Furthermore in the recent years, people gradually value the shore protection from different viewpoints, like environment, recreation, and ecology. The objectives of the shore protection are diversified by these new demands.Therefore, the purpose of this study is to evaluate the strategy on how to conjoint soft solutions into the current hard engineering structures for beach erosion control throughout Taiwan coast. Meanwhile, this paper will also introduce environmentally, user-oriented, and technically sound creditable protection works to meet the new trends of shore protection. For application purpose, two local sites in the southwestern Taiwan coast are selected for field experimental study to integrate the proposed soft solution with hard shore protection system at present. Furthermore for coastal management purpose, this paper also collects and analyzes hydro-morphodynamic data around Taiwan in order to identify beach erosion mechanism. Lastly, the results are presented by database and geographic information system. 相似文献
11.
Chirananda De 《Marine Georesources & Geotechnology》2002,20(3):209-220
The marine polychaete Diopatra cuprea (Bosc) produces tubes that protrude above the sediment surface. To the part above the sediment surface the worm attaches foreign particles. A sharp boundary separates the parts above and below the sediment surface. With subsequent erosion, part of the tube without attached particles becomes exposed and this exposed part indicates the amount of erosion. With subsequent sedimentation, the tubes are enlarged upward and the sharp boundary is found below the sediment surface indicating the amount of subsequent sedimentation. This mode of construction of tubes during an average life span of two years renders tubes as simple but excellent natural tools for precise and easy measurement of the latest annual rates of erosion and deposition in coastal areas, data that are essential for the solving of coastal engineering and geoenvironmental problems. Comparison of this tool with expensive long-term coastal profiling data in four areas in the Bay of Bengal coast indicates its correctness and high applicational value.
This revised model can be applied to modern coastal environments only for calculating latest annual rates of both erosion and deposition as correctly as latest physical techniques. Being based on the similar organosedimentary principle, it distinctively contrasts with the earlier model of Myers which provides information on the amount of sediment accumulation only without any time connotation and, it may generate erroneous results if applied to the geologic past unless some limitations evolved in the processes of dewatering, compaction, lithification and diagenesis are removed. 相似文献
This revised model can be applied to modern coastal environments only for calculating latest annual rates of both erosion and deposition as correctly as latest physical techniques. Being based on the similar organosedimentary principle, it distinctively contrasts with the earlier model of Myers which provides information on the amount of sediment accumulation only without any time connotation and, it may generate erroneous results if applied to the geologic past unless some limitations evolved in the processes of dewatering, compaction, lithification and diagenesis are removed. 相似文献
12.
薛春汀 《海洋地质与第四纪地质》2002,22(2):121-125
珊瑚礁海岸海滩和礁坪是海岸作用是活跃的部分，也是近几十年来与海岸发育，海岸侵蚀联系最密切的部分，这一部分高潮时被淹没，低潮时完全出露或大部分出露，使得在此进行地质填图成为可能，这样的地质图可以提供许多信息，如沉积物粒度分布规律，沉积物来源和搬运方向，海滩岩所指示的古海岸线位置，人类活动特别是海岸工程对沉积物分布的影响以及海岸线的变化过程和趋势，在礁坪上开挖的人工水道内测流，能够了解水流的性质以及是否有足够的速度搬运沉积物，从而了解人工水道对海岸的影响和预测海岸的状态，这些方法也可以用于大陆泥质和砂质第岸侵蚀的研究。 相似文献
13.
14.
Jan Kavan 《Marine Geodesy》2020,43(3):234-247
AbstractChanges in the position of the shore in the vicinity of Kapp Napier in central Svalbard was described. The overall advance of the shore was probably related to high input of the sediment material originating from erosion of the coastal areas south of the Kapp Napier locality and high input of material from adjacent glacifluvial system of Nordenskiöld glacier with its marginal water streams. Fast evolution of glacier retreat related processes after the Little Ice Age was a secondary driver of the dynamic changes in the central Svalbard coastal areas especially in the first half of the 20th century. The highly dynamic longshore currents in the area altogether with still ongoing glacio-isostatic uplift played an important role in the process as well. The most active parts of the shore experienced advance of almost 100 m since 1908 to 2009. On the other hand, a small part of the coast retreated of about 20 m. Most of the study area experienced aggradation (65%), 30% of the coast was stable and about 5% of the coast has undergone minor retreat. The maximum aggradation rate of 0.96?m/year corresponds well with similar sites in the vicinity. 相似文献
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16.
海阳市砂质海岸资源丰富,延绵近120 km,尤以万米沙滩浴场著称,但近年岸滩侵蚀严重影响其社会经济发展.本研究基于海阳市羊角畔两侧长约20 km典型砂质海岸连续3 a的海岸线蚀和典型剖面蚀淤调查,定量化研究海滩侵蚀及其变化,辅以一维数值模型,研究人类活动影响下的泥沙运动特征和海滩侵蚀机制.研究结果表明,调查区42.5％和5.90％的砂质海岸分别处于侵蚀和强侵蚀状态,羊角畔东侧海岸侵蚀强度高于西侧,海阳港至海阳核电厂之间海滩侵蚀强度最高,海滩侵蚀强度与人类活动扰动程度密切相关.海岸工程、临海养殖和人为采砂导致海阳市部分砂质海岸侵蚀严重的主要原因,导致羊角畔两侧海岸侵蚀机制也不同.基于各岸段侵蚀机制特征有针对性地提出退养还滩、凸堤拆除和沙滩喂养等对策,以减缓海阳砂质海岸侵蚀威胁. 相似文献
17.
布容法则及其在中国海岸上的应用 总被引：12，自引：1，他引：11
布容（Ｂｒｕｕｎ）法则是预测海平面上升引起海岸侵蚀最早的方法也是最简单的方法。根据中国砂质和淤泥质海岸的情况,布容法则可定性地解释海平面上升与海岸侵蚀的关系,在满足它要求条件的海岸地段和发育时期,用它预测海岸侵蚀或许是可能的。但是,若不严格审查海岸环境和条件,把它作为海平面上升情况预测海岸侵蚀的普遍模式,有待更多的研究加以证明。 相似文献
18.
河北昌黎典型海岸沙丘的沉积构造及其发育模式 总被引：3，自引：0，他引：3
采用探地雷达探测了昌黎海岸沙丘区典型横向沙脊和新月形沙丘的沉积构造,据此初步揭示了研究区海岸沙丘的沉积序列特征和发育过程。结果表明,昌黎海岸带在2 000 a BP波浪作用下发育滨岸沙坝,沙坝主要以向海向陆缓倾斜的沉积构造为主,现今的风成沉积发育于滨海相沙坝之上。海岸带向海一侧经历了潮上带前丘到横向沙脊的过程,横向沙脊在东北风的作用下主要发育向陆倾斜的高角度交错层理,同时由于向岸合成风力的阶段性变化,这些层理的倾角略有差异,记录了海岸带风沙活动的周期性变化;内侧新月形沙丘由4组倾角不同的层理组成,被较大规模的二级界面分隔,复合新月形沙丘(链)经历了由盾状沙堆到典型新月形沙丘的加积发育并遭受风蚀的过程。 相似文献
19.
The barrier-inlet system along the Gulf Coast of peninsular Florida has one of the most diverse morphologies of any barrier system in the world. The delicate balance between tidal- and wave-generated processes on this low-energy coast permits only slight changes in either of these processes to result in significant and rapidly developing morphologic responses. Some of these responses are the result of natural phenomena such as hurricanes opening tidal inlets, closure of inlets due to longshore transport of sediment, and changes in the availability of sediment. Tidal prism is the primary factor in controlling inlet morphology and is greatly influenced by anthropogenic activities in the backbarrier area. Human activity has also modified the coast in many ways over the past several decades, beginning with the construction of the first causeways in the 1920s. The various modifications by development have resulted in important morphodynamic changes in the barrier-inlet system. These include hardening the coast on the beach and at inlets, dredging and filling in backbarrier environments, and construction of fill-type causeways connecting the islands to the mainland. Construction of seawalls and jetties has inhibited normal coastal processes. Examples include the downdrift erosion at Blind Pass and Big Sarasota Pass. Construction of fill-type causeways between the barriers and the mainland has created artificial tidal divides that reduce the tidal prism at some inlets, thereby resulting in instability or closure such as Blind Pass and Dunedin Pass. This is further exacerbated by dredge and fill construction that reduces tidal prism by reducing the area of open water in the backbarrier. Dredging of the Intracoastal Waterway also results in a negative impact on selected inlets by channeling tidal flux away from some inlets. Impacts of these changes inhibit the barrier/inlet environments from responding to open coast processes. 相似文献
20.
Sediment supply and pre-existing shoreline morphology are crucial factors in controlling coastal changes due to sea-level rise. Using examples from both southeast and northeast Ireland, it can be shown that sea-level change may trigger a sequence of events which leads to both static and dynamic shoreline equilibrium. Cliff erosion and longshore sediment movement in east Co. Wexford has led to injection of sediment onto the shelf, and the growth, under both wave and tide regimes, of linear offshore shoals. These shoals now control the pattern of shoreline erosion and provide a template for possible stepwise evolution of the coast under any future sea-level rise. In contrast, the nearby coast of south Co. Wexford comprises a series of coarse clastic barriers moving monotonously onshore, via overwash processes. Here the behavior of the barrier is conditioned by the antecedent morphology of both the beach face and stream outlet bedforms. Finally, the rock platform coast of Co. Antrim presents a far more resistant shoreline to incident marine processes, yet even here there is strong evidence of present process control over so-called ‘raised’ platforms and embayments. It is concluded that coastal sediment supply and dynamics, together with coastal morphology and its interaction with waves, present a far more complex variety of sea-level indicators than is normally acknowledged. 相似文献