山西地震台网地震预警时间及盲区半径分析

影响地震预警能力的关键技术指标是预警时间及预警盲区。通过分析山西地震台网勘选完成的1 101个预警台站布局,计算地震台站平均台间距,根据预警盲区半径与台间距关系式得出盲区半径。根据计算结果及相关分布图,分析认为,在预警区内,平均台间距及盲区半径分布与地震活动的相关性较高,勘选完成的地震预警台站布局比较合理。     

Geochemical and statistical analysis of trace metals in atmospheric particulates in Wuhan, central China

The geochemical characteristics of trace metals (As, Cr, Co, Cd, Cu, Mn, Ni, Pb, V and Zn) in PM10 in Wuhan, the biggest metropolitan in central China, as well as their sources and contributions were analyzed. As PM10 has been the principal contaminant of air in Wuhan for years, concentrations of trace metals were measured in PM10 using high-volume samplers at one urban (Hankou) and one industrial (Changqian) site in Wuhan between September 2003 and September 2004. Based on the results, PM10 in Wuhan is characterized by relatively high levels of As, Cd, Mn, Pb and Zn compared with other Asian cities. The time-series of these elements indicated that As, Cu and Zn at both sites have similar trends, whereas Pb levels showed different patterns due to different emission sources. Factor analysis was applied to the datasets focusing on the apportionment of the mass of selected trace metals. Results indicate that Pb, Cd and As have a common source (smelting) at both sites, whereas the sources of Ni vary from coal combustion and steel in Changqian to mineral and traffic in Hankou.     

Identifying sources and hazardous risks of heavy metals in topsoils of rapidly urbanizing East China

With rapid economic and social development, soil contamination arising from heavy metals has become a serious problem in many parts of China. We collected a total of 445 samples (0–20 cm) at the nodes of a 2 km×2 km grid in surface soils of Rizhao city, and analyzed sources and risk pattern of 10 heavy metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn). The combination of Multivariate statistics analysis and Geostatistical methods was applied to identify the sources and hazardous risk of heavy metals in soils. The result indicated that Cr, Ni, Co, Mn, Cu, and As were mainly controlled by parent materials and came from natural sources. Cd and Hg originated from anthropogenic sources. Pb and Zn, belonging to different groups in multivariate analysis, were associated with joint effect of parent materials and human inputs. Ordinary Kriging and Indicator Kriging suggested that single element and elements association from the same principal components had similar spatial distribution. Through comprehensive assessment on all elements, we also found the high risk areas were located in the populated urban areas and western study area, which could be attributed to the higher geological background in the western part and strong human interference in the eastern part.     

井水位前驱波普遍性问题的探讨

以山西、河北、内蒙等地5口映震能力较强的地下水位观测井为研究对象,对井水位前驱波普遍性问题进行了探讨.结果表明,强震井水位前驱波现象较为普遍,其比例可达65.1％(41/63);相同地震不同观测井前驱波特征各不相同,同一观测井在不同地震前的特征也各异,这可能与不同观测井具有不同的井-含水层结构以及不同地震前有着不同的震源参数有关;与单井水震波相比,震前有前驱波记录的次数略低于水震波,其比例在39.7％～50.7％之间;震前有前驱波记录的观测井占研究区观测井总数的比例可达66.7％.