云南省MS≥6.0地震序列的基本特征   总被引：1，自引：1，他引：1  

刘丽芳  苏有锦  付虹  李永莉  蔡静观 《内陆地震》2002,16(1):62-68

选取了云南省 196 5— 2 0 0 0年的 19个 MS≥ 6 .0地震序列 ,利用震后 30天的余震资料 ,分析了各地震序列的震级结构。运用古登堡—里克特关系式及大森—宇津公式分别计算了各余震序列的 b值和 p值。结果表明 ,云南省每一次 7级或 6级地震发生后 ,均有大量余震发生 ,但余震活动的强度和频度在各序列之间存在较大差异 ,其原因可能与震源区的介质、构造差异有关。计算得到的 b值为0 .38— 0 .70 ,b值的大小体现出了一定的区域特征 ;p值大多接近或大于 1.0 ,但看不出区域特征。在主震—余震型和双主震—余震型地震序列之间 ,b值、p值看不出显著差异  相似文献   

浅议科技工作者发表论文立足国内中文期刊的长远价值和实施措施     

孙振凯 《山西地震》2014,(4):46-47

对科技工作者发表论文立足国内中文期刊的价值做了较深入的分析,并提出实现这一目标相应的政策措施。  相似文献   

泉州数字地震台速报震级偏差分析与校正     

谢文杰  尤宇星  张有明  黄圣棕  吴淑美 《华南地震》2012,(2):92-98

选取2004-01～2007-11共180多个速报地震,经震中距校核后测算的MS震级与全国大震速报台网发布的MS震级比对,得出泉州台在震级测算方面的偏差情况。并根据不同地震的相应特征,确定相应的震级校正值,以此提高泉州台的地震速报精度及作为提供日常处理地震资料数据的技术依据。  相似文献   

A new method for determining threshold in using PGCEVD to calculate return values of typhoon wave height     

罗耀  朱良生  胡金鹏 《中国海洋工程》2012,26(2):251-260

In using the PGCEVD (Poisson-Gumbel Compound Extreme Value Distribution) model to calculate return values of typhoon wave height, the quantitative selection of the threshold has blocked its application. By analyzing the principle of the threshold selection of PGCEVD model and in combination of the change point statistical methods, this paper proposes a new method for quantitative calculation of the threshold in PGCEVD model. Eleven samples from five engineering points in several coastal waters of Guangdong and Hainan, China, are calculated and analyzed by using PGCEVD model and the traditional Pearson type III distribution (P-Ⅲ) model, respectively. By comparing the results of the two models, it is shown that the new method of selecting the optimal threshold is feasible. PGCEVD model has more stable results than that of P-Ⅲ model and can be used for the return wave height in every direction.  相似文献   

A variational method for correcting non-systematic errors in numerical weather prediction     

AiMei Shao  Shuang Xi  ChongJian Qiu 《中国科学D辑(英文版)》2009,52(10):1650-1660

A variational method based on previous numerical forecasts is developed to estimate and correct non-systematic component of numerical weather forecast error. In the method, it is assumed that the error is linearly dependent on some combination of the forecast fields, and three types of forecast combination are applied to identifying the forecasting error: 1) the forecasts at the ending time, 2) the combination of initial fields and the forecasts at the ending time, and 3) the combination of the forecasts at...  相似文献   

Participation and resistance: Alternative seafood marketing in a neoliberalera     

《Marine Policy》2017

This paper suggests that detrimental effects of certain neoliberal fisheries policies are key drivers behind the development of alternative seafood marketing programs in North America. It examines the structures, market and non-market values, and challenges of these programs. The primary aim of the research, based on interviews involving 20 programs and a conference workshop, was to advance understanding of the market value of alternative seafood marketing to fishers and communities. However, the importance of a broader set of non-market values was repeatedly highlighted by those engaged in these programs. Overall, the research suggests that alternative seafood marketing can enable fishers to participate in fisheries managed by neoliberal, market-based policies, through the promotion of market values along their diverse value chains. At the same time, alternative seafood marketing appears to resist market-based fishing systems, sometimes through the promotion of broader, non-market outcomes. Common challenges along these alternative seafood value chains highlight the structural conflicts that exist while simultaneously participating in and resisting neoliberal fisheries structures.  相似文献   

Impacts of current EU regulation on the UK whitefish value chain     

《Marine Policy》2017

Cod and haddock are two of the “big 5” UK supermarket fish species and intrinsic to fish and chip shops nationwide. UK whitefish fleets produce a significant amount, however there is a reliance on imports to maintain supply. The UK is in a strong position to compete for raw material from Iceland and Norway given high prices paid for imports and investment by Icelandic and Norwegian companies in the UK. Regarding UK production of whitefish, the European Common Fisheries Policy landing obligation has introduced significant uncertainty. To avoid discarding of any quota stock, fishing may be stopped before all target stocks quota is reached. For demersal fleets, there is a transition period between 2016 and 18 where target stocks are introduced according to Advisory Council and EU agreement and Article 15, with all quota stocks from 2019. As the capacity of the fleets balance to the new regulations, supply will likely return and if maximum sustainable yield (MSY) is reached in 2020 then an increase in TACs from current levels is likely too. However, markets and industries can change in a short period. Particularly, most processing companies are small to medium size enterprises and those that concentrate on cod and haddock may have to adjust their business. Fleets could be resilient to such short term reductions in landings however this cannot be assumed. The competitiveness of producers will surely be affected in the short to medium term as a result.  相似文献   

Value chain analysis and small-scale fisheries management     

《Marine Policy》2017

A value chain analysis is conducted to identify upgrading, that is, improvements in quality and product design that enable producers to gain enhanced value or through diversification in the product lines served. However, a range of data and information of use to managing small-scale fisheries can be also be produced. Eight value chain studies, carried out for specific fish species in different locations around the Philippines, are examined. Policy and management lessons learned and interventions resulting from the value chain analysis for small-scale fisheries management are discussed. Recommendations for using value chain analysis in small-scale fisheries management include stricter regulation on size limits of harvest, monitoring schemes, certification processes, post-harvest facilities, seasonal closures, social enterprises, credit facilities, and habitat protection.  相似文献   

Market assessment on the incentives and disincentives for the adoption of sustainable practices along the tuna value chain in Region 12, Philippines     

《Marine Policy》2017

With the world's increasing demand for tuna and the subsequent exhaustion of tuna stocks, this paper tries to assess the different attempts and/or practices that lead towards sustainability along the tuna value chain in the Philippines. In terms of economic gains, the net margins analysis, was used to measure the level of income of the actors which was considered as a factor that could possibly incentivize the adoption of sustainable practices, along with other market phenomena which were reviewed in this paper. These significant practices in the market include the provision of price premiums for the capture of mature tuna and the stringency of the market in terms of eco-labelling and certifications in contrast to the indifference of the local Philippine market in terms of preference. Lastly, having purse seine as a less sustainable method of tuna fishing, it was seen that there is a lack of incentive for them to adopt more sustainable practices.  相似文献   

北京市区居住环境的区位优势度分析   总被引：28，自引：6，他引：22  

张文忠  刘旺  孟斌 《地理学报》2005,60(1):115-121

首先选取服务设施、自然环境、交通状况、区位条件等因子作为北京市城市内部居住环境区位优势度的评价要素;然后构建评价模型,对北京市不同区域居住环境进行区位优势度评价,并分析其空间特征;进一步又研究了居住环境区位优势度与住宅价格的空间关系,以及与居民居住区位选择行为的关系;最后得出结论为,居住环境区位优势度空间变化趋势与商品房价格的空间分异以及居民居住区位选择的空间偏好具有相似性,即居住环境区位优势度高的地区商品房价格也相对较高,也是居民居住空间偏好地区。  相似文献