Fewexamplesof EM methodsappliedto volcanoesand geotermal ...

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Few examples of EM methods applied to volcanoes and geotermal systems in north Chile Daniel Díaz Universidad de Chile

Transcript of Fewexamplesof EM methodsappliedto volcanoesand geotermal ...

Few examples ofEMmethods applied tovolcanoes andgeotermalsystems innorth Chile

DanielDíazUniversidaddeChile

SanPedro– Linzor volcanic chain(RenzoMancini)

Inthisareaitwaspossibletoseehighvariationsinthetopography,wherefor15kminthehorizontaldirectionwehave2kmvariationintheverticaldirection,showingahighcontrastinthewestandeastsidesofthevolcanicchain,finallythisimportanttopographyinfluenceshowingamismatchinthedata,creatingtheneedtoconsiderthetopographyintheinversiontocorrectthat,consideringthisanormal conditionsinthefield,weperformedacriteriatodeterminatethediscretizationthehorizontaldirectionforcaseswithahightopographycontrast.Wenote2importantfeatures,

first:itwasnecessarytoperformthemostnegridunderthestations,inthiscaseweusealogarithmicincrease,whichstartunderthestationsandincreaseupwardsanddownward,creatingamorenegridunderit.Forthisweusethe3DGridprogramperformedbyNaser Meqbel.

Second:inthisresearchwehavedifferenceof2kminthehorizontaldirectionbetweenstations,thereforeitwasnopossiblemakethefirstconsiderationunderallstations,thenfordecidewherecreatethemostnegrid,itwasnecessaryconsidertheconductivityunderit,prioritizingafinergridunderthemostconductivitystationstoavoidoverlapinthesamediscretizationblock,becauselessresistivitygeneratelowerpenetrations(skindepth analysis).

Danielacápongoelcriteriofinalquesetomoparadefinirelanchodelagrilla(eseldelpaper)

Primerosajustesantesdelatopo Ajustefinaldespuésdelatopo

Graficoquemuestracomomejoraeltipper,aumentandoeltamañodelagrilla,de13kmHasta155km

155kmenXeY 13kmenXeY

ElTatio– LaTortaGeothermalField(ArielFigueroa)

ElTatio– LaTortaGeothermalFieldElTatiogeyserfieldcontainsmorethan80activegeysers(8%oftheworld)andislargestinthesouthernhemisphere.ItislocatedinnorthernChileatanelevationof4200to4300m.Diverse thermalfeatureshavebeenreported,includinggeysers,springs,perpetualspouters,mudpools,mudvolcanoes,andfumaroles.ThefieldissituatedamongHoloceneandesiticstratovolcanoesanddomes(LaTorta),whichmightprovidetheheatforthegeothermalsystem,butnohistoricaleruptionsweredocumented.

MTPointsinElTatio19mt pointsweremeasuredduringthisyear

Dimensionalanalysis

Preliminary results:inversionmodel (rms:1.59)

Datafitting