A catastrophic natural disaster chain of typhoon–rainstorm–landslide–barrier lake–flooding in Zhejiang Province,China

On August 10, 2019, due to the effect of a rainstorm caused by Super Typhoon Lekima, a landslide occurred in Shanzao Village, China. It blocked the Shanzao stream, forming a barrier lake, and then the barrier lake burst. This is a rare natural disaster chain of typhoon–rainstorm–landslide–barrier lake–flooding. This study was built on field surveys, satellite image interpretation, the digital elevation model(DEM), engineering geological analysis and empirical regression. The purpose was to reveal the characteristics and causes of the landslide, the features and formation process of the barrier lake and the dam break flooding discharge. The results show that the volume of the landslide deposit is approximately 2.4 × 105 m3. The burst mode of the landslide dam is overtopping, which took only 22 minutes from the formation of the landslide dam to its overtopping. The dam-break peak flow was 1353 m3/s, and the average velocity was 2.8-3.0 m/s. This study shows that the strongly weathered rock and soil slope has low strength and high permeability under the condition of heavy rainfall, which reminds us the high risk of landslides and the importance of accurate early warning of landslides under heavy rainfalls in densely populated areas of Southeast China, as well as the severity of the disaster chain of typhoon–rainstorm–landslide–barrier lake–flooding.     

九曲练溪十里画廊--缙云仙都火山地貌景观

缙云仙都是一个以火山地质景观为特色,融田园风光与人文史迹为一体的国家级重点风景名胜区.不同时代,不同类型的火山岩和火山活动,形成不同的火山地貌,构成一幅九曲练溪的十里画廊.本文特别介绍了新近发现的一个小型火山颈--步虚山凌虚洞火山通道,这是一个难得多见的深及地下60多m火山通道自然剖面.     

Evaluating value of natural landscapes in China

Natural landscapes consist of the natural substances, environment, and phenomena, all of which provide many benefits to people, including a sense of place, sightseeing, relaxing, and recuperating. However, the economic value of natural landscapes has only been recognized in recent decades, and the resulting large-scale decline and degradation of ecosystems now severely threatens the sustainable provision of their services to society. There is an emerging consensus that natural capital should be incorporated into the current socioeconomic accounting system. Many studies valuated natural resources at local and regional scales, but there are very few empirical studies at a national level. To provide a benchmark for natural landscape management on a national scale, we use the travel cost method(TCM) and the contingent valuation method(CVM) to determine the economic value and the spatial distribution of natural landscapes across China. Our results show that the total economic value of China′s natural landscape was 9.75 × 10~(11) U.S. dollars(USD) in 2012. Of this value, the highest proportion was in the eastern and southwestern regions of China, which accounts for 23.7% and 18.3%, respectively. The provinces of Guangdong, Sichuan, Yunnan, Inner Mongolia, and Heilongjiang were the top five in terms of the largest number of natural landscapes and largest economic values. Together, these five provinces accounted for 32.9% of the total number of natural landscapes and 29.4% of the total economic value in 2012. We believe this study will increase awareness of the value of natural landscapes, and more importantly provide a scientific basis for resolving conflicts between development and resource conservation.     

The discovery of magnetotactic/magnetosensitive bacteria

Magnetotactic bacteria orient and migrate along magnetic field lines in aquatic habitats. The first     

Quantitative evaluation and spatial differentiation of eco-environmental livability in Zhejiang Province,China

The scientific analyses of the spatial patterns of regional eco-environment livability, along with the explorations of the correlations between ecoenvironments and population and economic activity distributions, are of major significance in the guidance of the coordinated development between social economies, natural resources, and environments. In this study, the topography, climate,hydrology, land cover, air quality, and the dangers presented by natural hazards in the study area were investigated in order to establish an evaluation model for the regional eco-environmental livability. Then,the observed spatial patterns and regional differences in the eco-environmental livability, as well as their relationships with the distributions of population and economic activities in Zhejiang Province, were investigated. The results showed that the ecoenvironmental livability in Zhejiang Province displayed a gradual decreasing trend from southwest to northeast, as well as from the mountains to the hills, valleys, and plains areas. During the compartmentalization of the eco-environmental livability, it was observed that the lowest livable area covered the largest population, accounting for approximately 29.64% of the total population in the study area. The higher livable areas covered the widest land areas, accounting for approximately 26.15% of the total area. Moreover, it was found that the eco-environmental livability in the mountain areas was higher than that in the plain areas in Zhejiang Province. Furthermore, the ecoenvironmental livability was found to have a significant exponential relationship with the population and GDP densities of Zhejiang Province,with the R~2 of the curve-fittings reaching 0.835 and 0.656, respectively. However, it was determined that the coefficient of the exponential function was negative, which indicated that a strong negative relationship existed between the eco-environmental livability and densities of the population and economic activities. It was assumed that the impacts of anthropogenic factors were the fundamental causes of this negative correlation. This study introduced two new factors(air quality and natural hazards) into the evaluation framework of eco-environmental livability.As a result, a more comprehensive model was established for the evaluation of eco-environmenta livability in certain segments of the study area Additionally, the correlation between ecoenvironment livability and human activities was discussed in-depth, which can potentially provide theoretical and practical guidance for the implementation of eco-livability in China, and possibly even those of other vast developing countries.     

Sources of sediment in tidal fl ats off Zhejiang coast,southeast China

The growth of tidal fl ats off Zhejiang coasts in southwestern China has provided substantial areas for local agriculture and construction activities. To evaluate modern and future development of tidal fl ats in the region, a good understanding of sediment sources is necessary. Previous research has concluded that the Changjiang(Yangtze) River is the dominant supplier of sediments to this part of the southeast Chinese coast, despite the fact that sediment delivery from this source has been decreased markedly in the past two decades. In this study, we investigated the sources of tidal fl at sediments, and the magnetic and geochemical properties of recent tidal fl at sediments along the Zhejiang coast were compared with those discharged from rivers. Magnetic and geochemical properties of the tidal fl at samples reveal statistically distinct sediment provenance groups. The magnetic and geochemical scatter plots show that the suspended sediment samples are naturally divided into two diff erent groups, one including the Changjiang River and Qiantang River material, and the other including the Jiaojiang, Oujiang, and Feiyun Rivers that located in the central and southern parts of the study areas. At last, a binary source of tidal fl at sediments along the Zhejiang coast was determined, with the substantial majority originating from local rivers, while a much smaller proportion emanates from the Changjiang River to the north. We conclude that the sediment contribution of the Changjiang River to tidal fl at development in the region has been markedly overestimated, with important implications for management.     

Mountain Land Use Planning of Metropolitan Suburbs： the Case of the Jinyun Mountain and Its Surrounding area, Chongqing, China

Open space of metropolitan suburbs in mountain region, has been increasingly becoming the coupling mosaic structure of industrial actions and landscape behaviors. However, the local governments, when making land use planning, often aim at economic development, and rarely refer to the coordination of compatibilities and conflicts between industrial actions and landscape behaviors in the mosaic structure. In this study land use in the Jinyun Mountain and its surrounding area, Chongqing is adjusted by gray multi-objective programming approach and local-level decision-making process to cope with conflicts between objectives for human welfare and objectives for landscape conservation. The results indicate that： 1） the compatibilities and conflicts among different behavior characters and different landscape types result in the compatibilities of landscape to human behavior; 2） a land use planning in the study area is produced based on the sustainable land use and social-eco development, which pays more attention to the resources and environment constraints and economic objectives, and follows the distribution law of rare resources; 3） in the study area, cultivated land of 1,207.27 ha can meet the demands for food and byproducts by the residents there, orchard land and forestland of 632.55 ha, 2,276.61 ha, respectively can provide enough spaee for the local people to improve their living structure and meet their demands for reereational activities, and urban residential land, rural residential land, mining land and transportation land of 1107.60 ha, 120.27 ha, 162.48 ha, 100.91 ha, respeetively can satisfy the resident＇s eeonomie development and infrastructures; 4） the equilibrium among industrial actions, landscape accessibility and ecological conservation can be obtained by analyzing the possible impaets of human activities on landscape eeologieal proeess in open spaee of metropolitan suburbs in mountain areas.     

Characteristics of Drought and Flood in Zhejiang Province, East China： Past and Future

On the basis of large amount of historical and measured data,this paper analyzed the regional,periodic,frequency,continuing,and response characteristics of droughts and floods in Zhejiang and proposed the conception of ratio of peak runoff.Main characteristics of droughts and floods in Zhejiang are as follows:1)The western Zhejiang region is plum rain major control area,and the eastern coastal region of Zhejiang is typhoon major control area.2)Within a long period in the future,Zhejiang will be in the long period that features droughts.3)In Zhejiang the 17th century was frequent drought and flood period,the 16th,19th,and 20th centuries were normal periods,while the 18th century was spasmodic drought and flood period.4)The severe and medium floods in Zhejiang were all centered around the M-or m-year of the 11-year sunspot activity period.5)There are biggish years of annual runoff occurred in El Ni?o year(E)or the following year(E 1)in Zhejiang.The near future evolution trend of droughts and floods in Zhejiang is as follows:1)Within a relatively long period in the future,Zhejiang Province will be in the long period of mostly drought years.2)Between 1999 and 2009 this area will feature drought years mainly,while the period of 2010-2020 will feature flood years mostly.3)Zhejiang has a good response to the sunspot activities,and the years around 2009,2015,and 2020 must be given due attention,especially around 2020 there might be an extremely severe flood year in Zhejiang.4)Floods in Zhejiang have good response to El Ni?o events,in El Ni?o year or the following year much attention must be paid to.And 5)In the future,the first,second,and third severe typhoon years in Zhejiang will be 2009,2012,and 2015,respectively.     

AVO character research of natural gas hydrates in the East China Sea

Natural gas hydrates are considered as strategic resources with commercial potential in the 21st century. Obvious BSR characteristics will be shown on seismic profiles, if there exist natural gas hydrates. The AVO method is one of the methods which can be used to identify and forecast lithologic characteristics and fluid properties by using the relationship between Amplitude and Offset. AVO anomaly is one of the significant signs to check out whether or not there is free gas below the BSR, so it can be used to detect natural gas hydrates from the seismic profile. Considering the geological and geophysical characteristics of the Okinawa Trough and making use of the techniques mentioned above, we can conclude that the conditions there are favorable for the formation and concentration of natural gas hydrates. By analyzing the data collected from the study area, one can discover many different anomalous phenomena on the seismic profile which are related to the existence of natural gas hydrates. Preliminary estimation of the natural gas hydrates in the Okinawa Trough shows that the trough is rich in natural gas hydrates and may become a potential important resources exploration area.     

浙江主要铀矿类型与铀矿石的溶浸性能特征

浙江铀矿资源丰富 ,我国四大铀矿类型在省内均有发现。作为一种特殊的战略性矿产资源 ,在我国国防和核电工业具有重要的地位 ,研究铀矿石的溶浸特性 ,对于铀矿资源的科学利用 ,服务于经济建设具有现实意义。本文通过对我省主要铀矿类型的介绍和溶浸性能特征的研究 ,旨在对省内主要铀矿类型矿石的溶浸性能作出初步评价