地磁资料质量评比的模式识别分析

本文用模式识别方法对台站地磁资料质量现况及各评比单基在综合评比中的作用进行了分析，并提出了建议。     

南极中山站极夜、极昼期间S_q~p、S_D的变化规律及特征

本文利用１９９１年度南极中山站的地磁资料，分析研究极夜（５、６、７月）及极昼（１１、１２月）期间Ｓ、ＳＤ的变化特征。研究结果表明，Ｈ、Ｄ、Ｚ三个分量的Ｓ、ＳＤ在极夜期间的变化幅度都小于极昼期间的变化幅度，Ｓ在世界时ＵＴ６时左右出现极值。这是由于在５、６、７月的太阳直射点在北半球，太阳紫外辐射和Ｘ射线辐射减少，在１１、１２月太阳的直射点在南半球，太阳紫外线和Ｘ射线辐射增大，致使空间电高层等效电流发生变化所产生。     

响应比法的地磁异常分析

将加卸载响应比的理论应用于地磁方法中，取太阳日照为加载，地磁垂直分量Ｚ为响应，应用马陵山地震台１９９３年１月～１９９５年１１月对相观测资料计算其响应比值。得出结果：响应比的变化在１９９５年９月２０日苍山５．２级地震前明显异常显示，分析认为，这一异常变化是苍山地震的前兆异常。     

Magnetic stratigraphy of Etan products. I-medieval lavas

Summary Mean magnetisation directions from 6 lava flows of questionable historical age have been determined. The results, which are based upon very stringent linearity criteria during demagnetisation, point out erroneous dating and the corresponding lavas can be ascribed to medieval activity of Mount Etna, as already suggested for some of the investigated flows, covering a time interval of some centuries around AD 1000. The site mean direction of AD 1536 historically dated lava flow agrees with a previous study (Tanguy et al., 1985), while the site mean directions of AD 1566 and AD 1169/812 differ significantly from those reported earlier. Neither AD 812 nor AD 1169 dating is consistent with the site mean direction of the related flow being compatible with an emplacement age possibly a few decades before AD 1000. The 3 lava flows historically dated AD 1595 exhibit different within site mean directions indicating that they cannot be referred to coeval activity of the volcano; the site mean direction of one of the flows is compatible with an emplacement occurring very close to AD 1000. The resulting SVC is significantly shifted eastwards with respect to that of previous study (Tanguy et al., 1985). However, its older part nearly overlaps the medieval Vesuvius SVC relocated to Etna. This indicates that the strict linearity analysis carried out during demagnetisation has allowed to clearly define the characteristic magnetisations of the investigated lava flows. The adopted procedure is appropriate for performing successful magnetic stratigraphy surveys in volcanic areas.     

总磁场强度的空间相关及北黄海ML5.0级地震异常

清理攻关后，虽然相关系数法被列为地磁学科预报地震的方法之一，但应用性较差，且震例不多，为了探讨该种方法预报地震的效果，本文对辽宁地区总磁场强度进行了空间相关分析。     

日偏食对低纬地磁场的影响

１９９５年１０月２４日日偏食期间，我们在海南省琼中进行了地磁场总强度的观测和分析，同时运用该地磁台三分量磁照图，分析了地磁Ｄ场Ｄ、Ｈ、Ｚ三分量在日偏食期间的变化特征。结果表明：日偏食期间，磁偏角初亏后逐渐偏东，食甚后偏西；水平强度和总强度初亏后逐渐变小，食甚后上升；垂直强度初亏后逐渐变大，食甚后约１个小时变小。