ARTÍCULO
The17July1999block-and-ash flow(BAF)atColimaVolcano:Newinsightson
Sarocchi, D., Sulpizio, R., Macías, J.L., Saucedo, R.,
Journal of Volcanology and Geothermal Research. 204: 40-56., 2011.
ABSTRACT:
abstract OnJuly171999,astrongexplosionoccurredatColimaVolcano(Mexico)thatproduceda10kmhigheruptive column.Thepartialcolumncollapseoriginatedablock-and-ash flow(BAF)that flowedtothesouth,alongthe SanAntonioandMontegranderavines,travelling3.3kmfromthevolcanosummit.The flow filledtheravines withavolumeestimatedat7.9×105 m3 .Theerosionofthesedepositsoccurredbetween1999and2002(time ofsampling),providingexcellentlongitudinaloutcropsthatallowedtheirdetailedtexturalstudy.Thestudy wascarriedoutbymeansofquantitativetexturalanalysis:(1)Rosiwalintersections,forcarryingoutvertical granulometricprofiles;(2)totalgrain-sizeanalysis,from−11to+9 ϕ;and(3)Fourierandfractalanalysisof theparticlemorphology.Grainsizeandmorphometricparametersobtainedwiththesemethodswereusedto identifyverticalandlongitudinalvariationpatternsintheBAFdeposit.Thegrainsizevariationsallowedto inferthemainparticlesegregationmechanismsthatactedduringtransportanddepositionofthestudied BAFs.Thetwomethodsusedforstudyingtheparticleshapemorphologiesyieldedresultswithdifferent accuracyandreliability.Inparticular,fractalanalyseshavebeenfoundtobethemosteffectiveindescribing theparticlesupportmechanismsthatactedduringtransportanddepositionofthestudiedBAFs. Theresultshighlighttheimportanceoftheinformationobtainedbymeansofthesetechniques,andprovide newinsightsintransportationanddepositionmechanismsofBAFs.