简介：TheYellowstonevolcanoisoneofthelargestactivevolcanoesintheworld,anditspotentialhazardsdemanddetailedseismologicalandgeodeticstudies.Previousstudieswithtraveltimetomographyandreceiverfunctionshaverevealedalow-velocitylayerinthecrustbeneaththeYellowstonevolcano,suggestingthepresenceofamagmachamberatdepth.Weuseambientseismicnoisefromregionalseismicstationstoretrieveshort-periodsurfacewavesandthenstudytheshallowshearvelocitystructureoftheYellowstoneregionbysurfacewavedispersionanalysis.WefirstobtainedacrustalmodeloftheareaoutsideoftheYellowstonevolcanoandthenconstructedanabsoluteshearwavevelocitystructureincombinationwithreceiverfunctionresultsforthecrustbeneaththeYellowstonevolcano.Thevelocitymodelshowsalow-velocitylayerwithshearvelocityataround1.3km/s,suggestingthatalarge-scalemagmachamberexistsatshallowlevelswithinthecrustoftheYellowstonevolcanicregion.

简介：江苏高邮、宝应Ms4．9级地震在极震区造成了数10间农村民居不同程度和不同方式的破坏，出现人员伤亡。震后对地震灾害现场进行震害调查与破坏原因研究，典型的震害特征包括砖砌体、砖木和砖混结构房屋局部倾倒、墙体贯通开裂、房顶瓦片掀翻和烟囱倒塌等。农村民居遭到破坏的主要因素包括：选址不当、施工质量较差、砂浆强度不够、缺少圈梁和构造柱等。同时，分析了竖向地震作用和鞭梢效应等地震效应，讨论了砖砌体和砖混结构抗震设计的加固方法和改善抗震性能的构造措施等，为农村民居的抗震设防和减轻震害损失等提供参考。