Resistivity imaging of Aluto-Langano geothermal field using 3-D magnetotelluric inversion

Cherkose, Biruk Abera; Mizunaga, Hideki

doi:10.1016/j.jafrearsci.2017.12.017

Cited by 27 publications

(27 citation statements)

References 7 publications

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“…Thus, it would be better to consider it as noise component. Validity of the estimated top of density contrasts ( Table 2 , column 4) could be guaranteed by comparing the gravity source depth results against the geologic stratigraphy ( Table 1 , Figure 6 ) produced based on well-log data ( Cherkose and Mizunaga, 2018 ). This source depth estimation method was used to estimate density horizons in northern part of Ethiopia ( Mammo, 2010 ), which lies close to our study area.…”

Section: Resultsmentioning

confidence: 99%

“…These wells depth ranges from 1300 m to 2500 m below surface ground level. Based on these drilling data information the geologic section was constructed along west-east oriented profile by different researchers ( Cherkose and Mizunaga, 2018 ; Wilks et al., 2017 ; Hutchison et al., 2016 ; Electroconsult (ELC), 1986 ). The section stratigraphy from top to bottom given as Silicic products; Lacustrine sediments; Bofa Basalt, tuff and breccias and Tertiary Ignimbrite layers ( Table 1 ).…”

Section: Datasets and Methodologymentioning

confidence: 99%

“…The parameters obtained from these data analysis are density, susceptibility, interfaces and corresponding causative source depths. In geological section described in section 2.1.3 , there is no Mesozoic and crystalline basement surface till depth of 2.5 km ( Cherkose and Mizunaga, 2018 ). The gravity data analysis in the study area show that the crystalline basement horizon is found at approximate mean depth of 3.0 km ( Kebede et al., 2020 ).…”

Section: Datasets and Methodologymentioning

confidence: 99%

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Depth estimates of anomalous subsurface sources using 2D/3D modeling of potential field data: implications for groundwater dynamics in the Ziway-Shala Lakes Basin, Central Main Ethiopian Rift

Kebede

Alemu

Nedaw

et al. 2021

Heliyon

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Quantitative analysis of potential field data are made in the Ziway-Shala lakes basin over an area bounded by 38 ° 00′ E - 39 ° 30′ E and 7 ° 00′ N - 8 ° 30’ N. Most previous geophysical studies in the region under consideration focus on mapping the deep crustal structures and undulation of the Moho depth. Only few studies are targeted at mapping the shallow subsurface structures. The main focus of this paper is mapping geometries of the major lithological and structural units of the shallow subsurface using gravity and magnetic data. The ultimate objective of the research is to understand the hydrogeological dynamics of the region through mapping interfaces geometries. Automatic inversions, 2D joint forward modeling and 3D inversion are the major techniques employed. The 2D Werner de-convolution based on both gravity and magnetic data along the rift axis showed source depths tending to deepen northwards. Source depths estimates determined by Source Parameter Imaging also showed similar tendency. This is further strengthened by the joint 2D forward modeling of gravity and magnetic data which showed the top of the basement is sloping northwards. The result of the 3D gravity interface inversion agrees with results of the above mentioned depth estimation techniques. Finally, the gravity power spectral analysis resulted in two depth estimates, 1.53 km and 2.87 km which approximate the positions of two density interfaces. The shallow depth interface is thought to presumably delineate the low density Fluvio-lacustrine sediments including the rift floor volcanic units and crystalline basement. Our investigation results agree with the results of previous seismic studies which identified low velocity (“sediment-volcanic”) horizon in the rift floor with low resolution. The information obtained with regard to water balance of the basin, salinity level of the lakes and the conceptual hydrological flow model appears to reveal that the groundwater flow in the study region is controlled by subsurface structures, particularly, the mapped interface topographies.

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Section: Resultsmentioning

confidence: 99%

Section: Datasets and Methodologymentioning

confidence: 99%

Section: Datasets and Methodologymentioning

confidence: 99%

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Depth estimates of anomalous subsurface sources using 2D/3D modeling of potential field data: implications for groundwater dynamics in the Ziway-Shala Lakes Basin, Central Main Ethiopian Rift

Kebede

Alemu

Nedaw

et al. 2021

Heliyon

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“…There are no indications for magma on the move as a source of the observed ground deformations. Instead, two dominating mechanisms, or a combination of both, likely trigger reoccurring periods of uplift and subsidence at Aluto: (i) elastic expansion of the highly crystalline magmatic body itself, related to expansion of an exsolved MVP (Chouet and Matoza, 2013) and, (ii), inflation of the hydrothermal system due to thermoelastic expansion and pressurization by the injection of magmatic volatiles (Chiodini et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

Integrated magnetotelluric and petrological analysis of felsic magma reservoirs: Insights from Ethiopian rift volcanoes

Samrock¹,

Grayver²,

Karakaş³

et al. 2021

Preprint

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“…The wide frequency interval in the magnetotelluric method can investigate earth's resistivity from the surface deeperthanother geophysical methods [2]. Resistivity is a geophysical parameter that is most effective in detecting potential reservoirs and determining the location of initial exploration wells [3].…”

Section: Introductionmentioning

confidence: 99%

Identification of "WS" geothermal field system by analyzing TE, TM, and TE-TM of 2D magnetotelluric inversion models

et al. 2019

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Magnetotelluric data has been carried out at the "WS" geothermal field to analyze the resistivity model resulting from 2D inversion of magnetotelluric data in TE, TM and TE-TM modes. Base on the three models produced, the mode is determined to produce the most representative model to assist in the interpretation of the "WS" geothermal system. There is a step of modes separation, namely TE (Tranverse Electric) and TM (Transverse Magnetic) modes in processing MT data. Each mode produces a 2D model with different conductivity properties. The analysis results of the three modes explain that TE mode is dominated by low resistivity with a range of values of 10-35 Ωm and medium resistivity with a value range of 35-250 Ωm and a vertical resistivity contrast. The TM mode describes the high resistivity in the Southwest and the center of the track with a value of more than 470 sehinggam resulting in lateral resistivity contrast. While the TE-TM mode produces a model that is not much different from TM mode, only the distribution of the resistivity value is a combination with TE mode. This mode describes the distribution of resistivity both vertically and laterally. Based on the analysis of the three modes, it can be concluded that the TE-TM mode is the mode that produces the most representative model. Interpretation model shows that from the TE-TM mode we have a low resistivity distribution (10-35 Ωm) represent a cap rock zone, reservoir rock with a medium resistivity distribution (35-380 Ωm), resistive zone with a high resistivity distribution (more than 380 Ωm), and the existence of the three of faults structures ro be a controller system of the "WS" geothermal.

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Resistivity imaging of Aluto-Langano geothermal field using 3-D magnetotelluric inversion

Cited by 27 publications

References 7 publications

Depth estimates of anomalous subsurface sources using 2D/3D modeling of potential field data: implications for groundwater dynamics in the Ziway-Shala Lakes Basin, Central Main Ethiopian Rift

Depth estimates of anomalous subsurface sources using 2D/3D modeling of potential field data: implications for groundwater dynamics in the Ziway-Shala Lakes Basin, Central Main Ethiopian Rift

Integrated magnetotelluric and petrological analysis of felsic magma reservoirs: Insights from Ethiopian rift volcanoes

Identification of "WS" geothermal field system by analyzing TE, TM, and TE-TM of 2D magnetotelluric inversion models

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