The horizontal boundary and top depth estimates of buried source using gravity data and their applications

Chen, Zhaoxi; Li, Mou; Meng, Xiaohong

doi:10.1016/j.jappgeo.2015.11.003

Cited by 9 publications

(5 citation statements)

References 32 publications

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“…The segments are characterized by wavenumber intervals which directly relate to the average depth to the top of the source. The steepest segment corresponding to low wavenumber values reflects deeper or regional sources (Chen, Mou, & Meng, 2016). The high-frequency segment, normally at the tail end of the slope, is related to noise from data processing and is normally disregarded during interpretation.…”

Section: Spectral Analysismentioning

confidence: 99%

Exploring Heat Sources Using Gravimetric Data: A Case Study of Magadi Geothermal Prospect, Kenya

Odero,

Githiri,

K’Orowe

2024

GEP

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Understanding the location of the subsurface heat sources is crucial for efficient geothermal resource exploration and exploitation. This study aimed to investigate the faults and the depth to heat sources for a geothermal system in Magadi, southern Rift Valley, through the integration of gravity mapping, 3D Euler deconvolution, and spectral analysis. Gravity mapping is a powerful geophysical method widely used to infer subsurface density variations, which are indicative of geological structures and volcanic intrusions that can be potential heat sources. The Volcano-Tectonic and Fluvial-Deltaic Sedimentation process of the Kenyan rift which encompasses the Magadi basin are responsible for geomorphic and geologic processes in the area. Alkali lava sheets of Magadi plateau trachytes covered with lacustrine sediments characterize 80% of the area. Deeper is the Tanzanian craton basement, overlain by Pliocene to Miocene volcanic and sedimentary rocks. A gravity survey with a data density of 2.375 stations/km 2 produced high-resolution anomaly and total horizontal derivative maps showing gravity highs between −180 mGals to −174 mGals along the eastern zone of the study area. A buried major fault trending N-S was delineated in the mid-upper region of the area by Euler solutions at an average depth of 350 meters. Deeper features associated with possible volcanic dykes and sills gave Euler depth ranges of 0.7 km to 2.2 km. Radial average spectral analysis showed depth to the top of shallow and deep features at 2.4694 km and 5.827 km respectively. The correlation between gravity anomalies, geological structures, and present hot springs supports the hypothesis that volcanic processes have played a significant role in the development of the geothermal system in the study area.

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Section: Spectral Analysismentioning

confidence: 99%

Exploring Heat Sources Using Gravimetric Data: A Case Study of Magadi Geothermal Prospect, Kenya

Odero,

Githiri,

K’Orowe

2024

GEP

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“…First, the power spectrum of the gravity data was computed and plotted with respect to the wavenumber (Fig. 11) and then the depth attributed to regional component was identified (Chavez 1987;Chen et al 2016;Guo et al 2013). Afterwards, the upward continuation to the height of 8 km was performed and the regional and residual gravity anomalies were formed, Fig.…”

Section: Gravity Datamentioning

confidence: 99%

Curie Point Depth, Geothermal Gradient and Heat-Flow Estimation and Geothermal Anomaly Exploration from Integrated Analysis of Aeromagnetic and Gravity Data on the Sabalan Area, NW Iran

Afshar

Norouzi

Moradzadeh

et al. 2016

Pure Appl. Geophys.

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Prospecting the geothermal resources in northwest of Iran, conducted in 1975, revealed several promising areas and introduced the Sabalan geothermal field as a priority for further studies. The Sabalan Mt., representing the Sabalan geothermal field, is a large stratovolcano which consists of an extensive central edifice built on a probable tectonic horst of underlying intrusive and effusive volcanic rocks. In this study, Curie point depth (CPD), geothermal gradient and heat-flow map were constituted from spectral analysis of the aeromagnetic data for the NW of Iran. The top of the geothermal resource (i.e., the thickness of the overburden) was evaluated by applying the Euler deconvolution method on the residual gravity data. The thickness of the geothermal resource was calculated by subtracting the Euler depths obtained from the CPDs in the geothermal anomalous region. The geothermal anomalous region was defined by the heat-flow value greater than 150 mW/m 2 . CPDs in the investigated area are found between 8.8 km in the Sabalan geothermal field and 14.1 in the northeast. The results showed that the geothermal gradient is higher than 62°C/km and the heat-flow is higher than 152 mW/m 2 for the geothermal manifestation region; the thickness of the geothermal resource was also estimated to vary between 5.4 and 9.1 km. These results are consistent with the drilling and other geological information. Findings indicate that the CDPs agree with earthquake distribution and the type of thermal spring is related to the depth of the top of the geothermal resource.

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“…These structures can be seen by using magnetic and gravitational anomalies along with other mathematical ltering techniques. For instance, the de nition of density/susceptibility interfaces (sourcedepths) using lters like upward continuation (Kebede et al, 2020), tilt depth (Chen et al, 2016;Salem et al, 2007), power spectral analysis (Likkason et al, 2013), 2D Werner deconvolution (Ku a Sharp, 1995; Mammo, 2012), and 3D Euler deconvolution (Mammo, 2010, Mammo, 2012Keating and Pilkington, 2004), power spectral analysis (Likkason et al, 2013;Mickus et al, 2007Tiberi et al, 2005, 2D Werner Deconvolution (Ku an Sharp, 1995; Mammo, 2012), 2D forward modeling, 3D structural model. The source depth estimation techniques stated above are just a few of the many available techniques.…”

Section: Introductionmentioning

confidence: 99%

Sediment thickness of subsurface anomalous Sources Determined by 2D/3D modeling of Potential field Gravity data: Implications for Sokoto Inland Basin Structures, NW, Nigeria

Abubakar

Likkason

Maigari

et al. 2023

Preprint

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Due to the promising potential for hydrocarbon exploration in Nigeria's inland basin, more and more emphasis is being paid to the structural setting associated with these basins, especially the current Sokoto basin. Lacoste and Romberg's CG-725 gravimeter collected a sizable amount of potential field gravity data for relative measurements in the region, which is used in this work. The depth of the Earth's subsurface was investigated in this study, which also provided information on the most likely process of emplacement for the bodies that gave rise to the anomalous structures in the Sokoto inland basin. The regional field, a plane with a gradient of 0.38 mG/km and an approximate 10° northeasterly dip, was used as a technique for regional-residual separation. The relative amplitudes of the negative Bouguer gravity anomaly in the region range from − 27.38 mGal to -74.88 mGal. In the southern part of the study area, a large positive anomaly with amplitude of 16.2 mGal can be detected on the residual anomaly map. The main techniques for applying enhancement filters include 2D forward modeling, analytical signal and tilt of angle derivative, directional filtering, power spectrum analysis, Werner deconvolution, and 3D inversion. The 2D spectral depth analysis of gravity data along the rift axis (NE-SW) indicates that source depths tend to deepen toward the south. The joint 2D forward modeling of gravity data provided more evidence for this, demonstrating that the top of the basement slopes both in the NW-SE and N-S directions. The 3D gravity model's findings concur with those derived from methods for estimating depth and surface geological properties. Two depth estimates—1.8 km and 2.93 km—that roughly match the locations of two density boundaries were obtained using the gravitational power spectrum analysis. In the up-dip parts of the Taloka and Gundumi-Illo Formations, intrusions were found at depths of 10–20 km and 5–10 km, respectively, according to gravity modeling of the upper crust. The quaternary faults and fractures in the Eocene sediment at Gwandu Continental Terminal are essential for the sediment cover of the regional hydrocarbon system.

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The horizontal boundary and top depth estimates of buried source using gravity data and their applications

Cited by 9 publications

References 32 publications

Exploring Heat Sources Using Gravimetric Data: A Case Study of Magadi Geothermal Prospect, Kenya

Exploring Heat Sources Using Gravimetric Data: A Case Study of Magadi Geothermal Prospect, Kenya

Curie Point Depth, Geothermal Gradient and Heat-Flow Estimation and Geothermal Anomaly Exploration from Integrated Analysis of Aeromagnetic and Gravity Data on the Sabalan Area, NW Iran

Sediment thickness of subsurface anomalous Sources Determined by 2D/3D modeling of Potential field Gravity data: Implications for Sokoto Inland Basin Structures, NW, Nigeria

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