Resumen de On the estimation of the maximum depth of investigation of transient electromagnetic soundings: the case of the Vizcaino transect, Mexico

Carlos Flores, José Manuel Romo Jones, Mario Vega

• español

  Probamos'un'método'propuesto'en'la'literatura'para' estimar'la'profundidad'máxima'de'investigación' (PMI)'de'sondeos'electromagnéticos'transitorios' (TEM)'de'bobina'central'con'datos'del'transecto' 9L]FDtQRXQSHU¿OGHVRQGHRV7(0TXHFUX]DOD SHQtQVXODGH%DMD&DOLIRUQLD6HFRQ¿UPDODYDOLGH] de'esta'técnica'al'comparar'la'PMI'con'la'interfase' más' profunda' de' 16' modelos' estratificados.' En' estos' sondeos,' todos' ellos' localizados' en' la' cuenca' Vizcaíno,' los' datos' medidos' no' están' afectados'por'polarización'inducida.'Los'modelos' indican' la' presencia' de' un' conductor' buzante' interpretado' como'una' zona'de'intrusión' salina' con'una'gran'extensión'lateral'de'más'de'70'km.' Los' otros' 22' sondeos,' localizados' sobre' rocas' tJQHDV\PHWDPyU¿FDVPXHVWUDQFDPELRVHQOD SRODULGDGGHORVYROWDMHVTXHLQGLFDQODSUHVHQFLD de'efectos'de'polarización'inducida.'Los'modelos' HVWUDWL¿FDGRV&ROH&ROHGHHVWRVVRQGHRVVXJLHUHQ una' disminución' importante' en' la' PMI.' Esto' es' FRQ¿UPDGR DO DQDOL]DU HO FRPSRUWDPLHQWR HQ profundidad' de' las' densidades' de' corriente.' También'se'analiza'el'nivel'de'ruido'de'un'conjunto' GHGDWRVTXHFRPSUHQGHFHUFDGHYROWDMHV de'tiempo'tardío''de'aproximadamente'400'sitios' 7(0DGTXLULGRVHQHOQRURHVWHGH0p[LFR1RVH encontró'una'diferencia'entre'los'niveles'de'ruido' estacionario'de'invierno'y'verano,'posiblemente' GHELGR D TXH SUiFWLFDPHQWH QR KD\ WRUPHQWDV eléctricas'en'esta'parte'de'México.

• English

  We'test'an'approach'proposed'in'the'literature'for' estimating' the'maximum'depth'of'investigation' (MDI)' of' inMloop' transient' electromagnetic' soundings' (TEM)' with' data' from' the' Vizcaino' WUDQVHFWDSUR¿OHRI7(0VRXQGLQJVFURVVLQJ the'Baja'California'peninsula. The'validity'of'this' DSSURDFKLVFRQ¿UPHGE\FRPSDULQJWKH0',ZLWK WKHGHHSHVWLQWHUIDFHRIVWUDWL¿HGPRGHOV##In' these' soundings,' all' located' over' the' Vizcaino' basin,' the' measured' data' are' not' affected' by' induced' polarization. The' models' indicate' the' presence' of' a' dipping' conductor' interpreted' as' a'zone'of'seawater'intrusion'with'a'large'lateral' extension' of' over' 70' km. The' remaining' 22' soundings,'located'over'igneous'and'metamorphic' rocks,' show' reversals' in' the' voltage' polarity,' indicating' the' presence' of' induced' polarization' effects. The'layered'ColeMCole'models' for'these' VRXQGLQJVVXJJHVWDVLJQL¿FDQWGHFUHDVHLQ WKH 0', 7KLV LV FRQ¿UPHG E\ DQDO\]LQJ WKH GHSWK behavior' of' the' subsurface' current' densities.' We'further'analyze'the'noise'level'of'a'data'set' comprising' close' to' 2000' lateMtime' voltages' of' DERXW  7(0 VLWHV DFTXLUHG LQ QRUWKZHVWHUQ Mexico.' No' difference' was' found' between' the' stationary' noise' levels' of' winter' and' summer,' presumably' because' near' thunderstorms' are' practically'absent'in'this'part'of'Mexico.

  Key'words:'transient'electromagnetic'sound