简介：ShanxiGrabenisinthemiddlepartoftheNorthChinaCraton,fromsouthtonorth.WiththeteleseismicdatarecordedbyRegionalSeismographNetworksandthetemporaryZBnet-WSeismicArrayaroundeastpartofShanxiGraben,wemeasuredthecrustalthicknessandvP/vSratiobeneatheachstationusingtheH-jstackofreceiverfunctions.Theobservedcrustalthicknessshowsobviouslateralvariation,increasinggraduallyfromeasttowestintheShanxiGraben.BeneaththeShanxiGrabenthecrustisrelativelythickerthanbothsidesofthesouthandthenorth.Inaddition,thevP/vSratiointhenorthofstudyzoneishigherthanthatinthesouth.ThehighestvP/vSratioexistsinthecrustoftheXindingbasinandtheDatongbasin.Ourstudyalsosuggeststhathighvelocityratiomightresultfromthestrongactivitiesofthemagmationandvolcanism.

简介：ThegeologicalstructureiscomplexintheHohhot-Baotouarea.SeveralearthquakeswithMS≥6.0haveoccurredintheareainhistory.ThisarticleselectedtheHohhot-Baotouareaasthestudyregionanddivideditinto2sub-regions,eachwithaspatialscopeof3°×2°,accordingtothespatialdistributionofML≥1.0earthquakesoccurringbetweenJanuary2001andApril2010,andthelayoutoftheseismicnetworkinthestudyregion.Averagevelocityratiosofrespectivesub-regionswerecalculated,andcomparativeanalysiswasmadeontheirtemporalandspatialvariations.Resultsshowthatthereareslightdifferencesbetweensub-regionsinthevariationamplitudeofaveragevelocityratiocurvesovertime,whichmostlyremainsbetween2.5%to2.584%.IntheHohhotarea,theaveragevelocityratiois1.722,significantlylowerthantheaveragevelocityratioof1.733intheBaotouarea.WepreliminarilyconcludedthatthiswasrelatedtothedistributionoffaultstructuresandpropertiesofundergroundmediaintheHohhotarea.

简介：BasedonarrivaltimedataofseismicphasesofML≥2.0earthquakesmeasuredatShanxiDigitalSeismicNetworkfortheperiodfromJanuary2001toOctober2014,V_P/V_SintheShanxiregioniscalculatedusingtheWadatisinglestationandmulti-earthquakemethod,andaninvestigationisconductedintothevariationbehaviorofV_P/V_SintheShanxiregionbeforeandafterthethreeearthquakesofMS≥4.5in2010.OurstudyfindsthatabnormalV_P/V_Sappearedearlieratdistantstationsbeforeallofthethreeearthquakes,whichisatthetimerangefrom6monthsto1yearbeforetheearthquakes,andlateratnearstations,atthetimerange10daysto2monthsbeforeearthquakes.Therefore,itspossibletonarrowdownthescopeofthelocationinearthquakepredictionfromthedistantandnearstationdata.ThecalculationsofDongshanseismicstationindicatethatthesizeoftheresidualoftheorigintimehasimpactonthedetailofV_P/V_Svariation,thus,appropriatethresholdsshouldfirstlybesetfortheresidualsoforigintimeateachseismicstationinpracticalapplication,toensurescientificandsteadyV_P/V_Scalculations.