简介:2009年4月22日、6月23日、8月31日和10月31日,在白洋淀鸳鸯岛、北田庄和圈头村芦苇(Phragmitesaustralis)台地3个垂直剖面(0~10cm、10~30cm和30~60cm)上采集了土壤样品,分析了不同季节的土壤理化因子和4种土壤酶活性的时空变化及其相互关系。结果表明,白洋淀芦苇台地土壤含水量随着土壤深度的增加而增加;土壤有机质含量随土壤深度的增加而减少,0~10cm表层土的有机质含量都在70g/kg以上;土壤的全氮和全磷含量随土壤深度的增加而减少,各采样地0~10cm表层土壤的全氮含量为2.04~3.41g/kg,全磷含量为0.71~1.14g/kg。3块采样地0~60cm土壤的蔗糖酶活性、碱性磷酸酶活性、脱氢酶活性和荧光素二乙酸酯(FDA)水解酶活性分别为0.53~28.56mg/g、0.44~2.36mg/g、1.62~12.18mg/g和8.07~172.65μg/g,表层土壤具有较大酶活性。芦苇台地4种土壤酶活性与土壤含水量呈显著负相关(p〈0.01),与土壤有机质含量、全氮含量、全磷含量呈显著正相关(p〈0.01)。
简介:AnearthquakewithMS5.8occurredon10March2011inYingjiangcounty,westernYunnan,China.Thisearthquakecaused25deathsandover250injuries.Inordertobetterunderstandtheseismotectonicsintheregion,wecollectedthearrivaltimedatafromtheYunnanseismicobservationalbulletinsduring1Januaryto25March2011,andpreciselyhand-pickedthearrivaltimesfromhigh-qualityseismogramsthatwererecordedbythetemporaryseismicstationsdeployedbyourInstituteofCrustalDynamics,ChinaEarthquakeAdministration.Usingthesearrivaltimes,werelocatedalltheearthquakesincludingtheYingjiangmainshockanditsaftershocksusingthedouble-differencerelocationalgorithm.OurresultsshowthattherelocatedearthquakesdominantlyoccurredalongtheENEdirectionandformedanupside-downbow-shapedstructureindepth.ItisalsoobservedthataftertheYingjiangmainshock,someaftershocksextendedtowardtheSSEoverabout10km.TheseresultsmayindicatethattheYingjiangmainshockrupturedaconjugatefaultsystemconsistingoftheENEtrendingDaYingjiangfaultandaSSEtrendingblindfault.Suchstructuralfeaturescouldcontributetoseverelyseismichazardsduringthemoderate-sizeYingjiangearthquake.