magnetotelluric and transient electromagnetic ... - Orkustofnun

Wameyo 434Report 21SWMenengai CraterTEM21NEmElevation (m)22002000180016001400TEM05TEM26TEM19TEM53TEM56TEM52TEM51TEM35TEM362000 4000 6000 8000 10000 12000 14000 16000 18000 20000 22000 24000 26000Horizontal distance (m)High resistivity coreresistivity cap in this profile is at shallow levels below TEM12, at about 1850 m a.s.l., but deepens tothe northwest. Surface manifestations are observed around TEM12, where the low-resistivity cap isclosest to the surface.Resistivity cross-section NE-SW also passes through the caldera in the Bahati area (Figure 29). Athick low-resistivity cap over a deep resistive core, below 1400 m a.s.l., at the southwest end of thissection marks the southern margin of the anomaly observed in the western area of the caldera fromprevious resistivity sections. To the northeast, the low-resistivity cap deepens until we get to TEM36where emergence of yet another system is observed below TEM09 with the emergence of a new highresistivitybody. Further to the northeast the low-resistivity layer reaches elevation of approximately2000 m a.s.l. For clarification, this system will here be called the Solai-system.TEM09TEM23FIGURE 29: TEM resistivity cross-section NE-SWTEM491841591401221108671645953494541363127232018151036.3 TEM resistivity mapsThe results of the surveyare also presented as isoresistivitymaps showingresistivity at a certaindepth.Iso-resistivity map at 1800m a.s.l. (Figure 30), cutsthrough the top of the lowresistivitycap where itreaches the highestelevation just west of theMenengai caldera. Due toinsufficient data in the areawest of the caldera the areais “open” to the west. Thelow resistivity in thenortheast shows the top ofthe low-resistivity capcovering the Solai system.The indication of the Solaigeothermal system, is onlyNorthings (m)10000000999500099900009985000998000099750009970000So laiTEM19TEM15TE M 17TEM16Olbanita swampTEN62Kampi ya motoTE M 21TEM22TEM06TEM 60TEM02TEM 61TE M 49TE M 50TEM45TEM23TEM20TEM18TEM12TEM44TE M 58TEM 42TEM47TEM57TEM09KabarakTEM28TEM43TEM 59TE M 13 BahatiTEM41TEM 48TEM36TEM 11TEM35TEM30 TEM31 TE M 32 TEM33TEM51TE M 34TE M 54TE M 52TEM37TEM56TEM03TEM40TEM01 TEM08TE M 10TEM07TEM53TEM46TEM55TE M 24TEM25 TE M 26TEM27TEM14TEM05 TE M 29TEM 39TEM38TEM04Nakuru town9965000160000 165000 170000 175000 180000 185000Eastings (m)FIGURE 30: TEM resistivity distribution at 1800 m a.s.l.m1276551403327231816141210851