汶川8.0级地震前龙门山地区小震活动与固体潮的关系     

李卫平  李昕  卢红艳  冯蔚 《高原地震》2011,23(1):68-70

通过对汶川8.0级地震前,龙门山地区小震活动与月球上中天、下中天时刻对应关系的讨论,得到龙门山小震活动与月球引潮力的低潮对应关系不明显.另外,对龙门山小震与固体潮理论曲线对应的讨论,得到每组小震的头震在接近固体潮曲线的谷底发生,即地震的发生与固体潮的低潮有关.在临近大震前,地震多发生在固体潮曲线的上升部位,即引潮力增长...  相似文献   

Radar Observations of Leonid Meteor Shower 2003     

Devulapalli Venkata Phani Kumar  Kammadhanam Chenna Reddy  Ganji Yellaiah 《Astrophysics and Space Science》2006,306(4):235-239

Observations carried out during Leonid meteor shower 2003, by using Indian MST radar (13.46^N, 79.18^E; dip 12.5^N) are used to determine the number density of meteoroids through the cross section of the meteor streams. Cross sections are calculated for a number of classes of echo duration (particle size). They are also used to determine the relative flux of the shower in particle size ranges producing radar meteor echoes having durations <0.4 s, 0.4–1 s and >1 s. Mean activity profiles along the Earth's passage through the stream show a systematic change of the peak activity and the width of the stream depending on the distribution of echo durations across the stream. The patterns of mass distribution index s are presented and discussed.  相似文献   

位置地图情境分类分级与切换研究     

齐晓飞  王光霞  薛志伟  袁田 《测绘软科学研究》2013,(6):13-18

情境建模是拓展移动地图应用,提供个性化位置服务的有效工具。本文鉴于目前的情境模型存在情境类型区分不清晰、不同情境之间难以切换的问题。首先,剖析了活动与情境分类分级的联系,提出了一种基于活动分层的位置地图情境分类分级方法;然后,在此基础上,研究了情境切换的方式与方法,建立了位置地图情境切换方式与方法之间的对应关系;最后,以用户去机场登机为例,进行了实际验证。  相似文献   

东北地区M≥5.0地震前中等地震集中活动的震兆研究     

曹凤娟  焦明若  王亮  王岩  李彤霞 《地震工程学报》2013,35(2):385-393

定义了描述东北地区中等地震活动增强的3个参量E、T和R,并对东北地区11次M≥5.0地震进行了统计分析.结果显示,东北地区地震活动具有明显的区域性特点:辽宁地区和嫩江断裂以西地区M≥5.0地震前均存在4级地震集中活动的现象,且预期的5级以上地震大部分发生在最近1次4级地震后的半年内;嫩江断裂以东地区5级地震前没有中等地震集中活动的特征.ETR方法在中等地震活跃后判定未来5级地震的震中时具有一定的指示意义.  相似文献   

第四纪盆地隐伏断层活动性的D-T法研究及应用   总被引：1，自引：0，他引：1       下载免费PDF全文

张路  曲国胜  朱金芳 《地震工程学报》2012,34(2):126-131,141

本文在跨断层钻孔勘探的基础上,针对钻孔联合剖面提出了钻孔沉积深度-时间(D-T)分析方法。该方法以深度为纵轴、沉积时代为横轴做每一钻孔的D-T曲线,分析同一钻探场地断层两侧D-T曲线反映的沉积速率的差别,判断断层的活动时代和错距。该方法在福州盆地和泉州盆地的城市活断层探测项目应用得到较好的结果。最后分析了该方法的影响因素,指出钻探场地的地形(古地形)的稳定平坦是D-T法的关键。  相似文献   

A possible correlation between solar activity and Earth's oblateness     

D. Basu 《Planetary and Space Science》2008,56(11):1485-1487

Recent observations demonstrate that Earth's dynamic oblateness (J₂), which has exhibited a decrease since 1979, suddenly increased around 1997 and the increase is still continuing. The decrease is attributed to post-glacial rebound from the mantle, and several causes, all of terrestrial nature, have been suggested to explain the sudden change in the trend. But the observations remain puzzling. On the other hand, close relationships are known to exist between many phenomena on the Earth with solar activity, and unusual behaviours of other planets have also been demonstrated to be correlated with solar activity. We show here that solar activity is significantly correlated with J₂, and is possibly responsible for the sudden increase in Earth's dynamic oblateness around 1997, the latter being due to an enormous increase in the correlation.  相似文献   

黑子半影内偶极运动磁特征的Hinode观测研究     

李珂君  申远灯  杨丽恒  姜云春 《天文学报》2009,50(3)

利用Hinode卫星观测的单色像和磁图,对出现在黑子半影内的35对偶极运动磁特征进行形态特征、运动速度以及低层太阳大气响应3方面的研究,得出以下结论:(1)偶极运动磁特征正负两极成对出现在黑子半影较垂直的磁场之间并向着半影外边界运动,间接验证了偶极运动磁特征起源于黑子半影水平磁场,在2-8小时的时间间隔内,同一位置上会反复出现形态特征和运动速度相似的偶极运动磁特征,为海蛇状磁力线模型提供了证据支持. (2)光球和色球在偶极运动磁特征向外运动过程中会出现增亮,说明偶极运动磁特征会加热中低层太阳大气.(3)偶极运动磁特征的出现位置和半影磁场结构分布符合非梳子状黑子半影结构特征.  相似文献   

Statistical Assessment of Photospheric Magnetic Features in Imminent Solar Flare Predictions   总被引：1，自引：0，他引：1  

Hui Song  Changyi Tan  Ju Jing  Haimin Wang  Vasyl Yurchyshyn  Valentyna Abramenko 《Solar physics》2009,254(1):101-125

In this study we use the ordinal logistic regression method to establish a prediction model, which estimates the probability for each solar active region to produce X-, M-, or C-class flares during the next 1-day time period. The three predictive parameters are (1) the total unsigned magnetic flux T _flux, which is a measure of an active region’s size, (2) the length of the strong-gradient neutral line L _gnl, which describes the global nonpotentiality of an active region, and (3) the total magnetic dissipation E _diss, which is another proxy of an active region’s nonpotentiality. These parameters are all derived from SOHO MDI magnetograms. The ordinal response variable is the different level of solar flare magnitude. By analyzing 174 active regions, L _gnl is proven to be the most powerful predictor, if only one predictor is chosen. Compared with the current prediction methods used by the Solar Monitor at the Solar Data Analysis Center (SDAC) and NOAA’s Space Weather Prediction Center (SWPC), the ordinal logistic model using L _gnl, T _flux, and E _diss as predictors demonstrated its automatic functionality, simplicity, and fairly high prediction accuracy. To our knowledge, this is the first time the ordinal logistic regression model has been used in solar physics to predict solar flares.  相似文献   

Can Marine Protected Areas be developed effectively without baseline data? A case study for Burrunan dolphins (Tursiops australis)     

《Marine Policy》2017

Marine Protected Areas (MPAs) are increasingly used to protect marine mammals from anthropogenic threats despite limited studies that assess their efficacy. The small population of Burrunan dolphins (Tursiops australis) that inhabit Port Phillip Bay (PPB), Australia, are genetically isolated, listed as threatened and are exposed to dolphin-swim tourism. This study aimed to identify areas within PPB where dolphins are most likely to rest, forage and socialise, and whether these behaviours occur frequently within Ticonderoga Bay Sanctuary Zone (TBSZ), the only protected area designated for dolphins within PPB. Here, a comprehensive activity budget for Burrunan dolphins was established and critical habitat identified. Behavioural data were collected from 51 independent dolphin groups during 67 boat-based surveys conducted in southern PPB between December 2009 and May 2013. Travel (63.9%) and rest (1.8%) were the most and least frequently observed behaviours, respectively. Forage (16.4%), mill (10.8%) and social (7.2%) accounted for the remainder of the activity budget. Results indicate that the broader PPB region is important for foraging, socialising and nursing dolphins, while TBSZ has proven importance for foraging dolphins. Thus, the implementation of TBSZ was a correct management decision and MPAs developed without baseline data can be effective for marine mammal conservation. Three candidate MPAs were objectively identified in areas that are hotspots for foraging and socialising Burrunan dolphins in southern PPB. The findings of this study will be used to inform current conservation management strategies. If implemented, the aim of the proposed MPAs will be to reduce impacts from anthropogenic disturbance, namely dolphin-swim tour vessels.  相似文献   

Study on vertical distribution and activity factor of P forms in sediments of three urban shallow lakes in People’s Republic of China     

Chao Wang  Li-min Zou  Pei-fang Wang  Zhi-ping Lin 《Environmental Geology》2009,57(8):1799-1806

The vertical variation of P forms in sediments of urban shallow lakes in China, Xuanwu Lake, Daming Lake and Mochou Lake, were sequentially extracted and measured with the method of SEDEX. The results indicated the TP content in the sediment profiles ranged from 371.94 to 777.25 mg kg⁻¹ for Xuanwu Lake, 1,308.14 to 4,632.63 mg kg⁻¹ for Daming Lake, and 995.49 to 1,860.71 mg kg⁻¹ for Mochou Lake. The results of sequential extraction showed that Ca-P and Fe-P were the main fractions. Meanwhile, the proportions of Bio-P to TP were 35.24% for Xuanwu Lake, 29.57% Daming lake, and 25.26%, for Mochou Lake, indicating a high potential of P releasing. The content of Bio-P was significantly and positively correlated with TP (r = 0.978, P < 0.01). Lake hydrations conditions played an important role in the distribution and contents of Bio-P and TP. In the region with macrophytes, the contents of TP and Bio-P were relatively low. Physicochemical properties of sediments were significantly related to the fraction distribution and P contents, and might play an important role in controlling P activity and mobility. Moreover, Fe showed an evident influence on P fraction and the ratio Fe/P might be good indicator to the contents and composition of active P in sediments.  相似文献