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