The aim of this study is to characterize the subsoil in the southern region of the North-Kivu province (DR Congo). Gravity and geomagnetic data were used in this study. Five different filters—the horizontal gradient ...The aim of this study is to characterize the subsoil in the southern region of the North-Kivu province (DR Congo). Gravity and geomagnetic data were used in this study. Five different filters—the horizontal gradient magnitude, the analytic signal, the tilt derivative, the horizontal derivative of tilt derivative and the tilt angle of horizontal gradient—enabled us to delineate the gravity and magnetic anomaly sources present in the shallow subsurface of the study area. The plains of the Rutshuru territory are dominated by sources of weak gravity anomalies and sources of very weak magnetic anomalies located almost in the same places. The southern part of Rutshuru territory and a large part of Masisi territory are underlain by shallow sources of high gravity and magnetic anomalies. Gravity and magnetic anomaly sources are almost identical in the study area. The shallow sources of gravity and magnetic anomalies encountered in our study area are more or less linear and connected. The numerous gravity and magnetic lineaments present in our study region have three major directions: oriented East-West, North-South and North-East-South-West.展开更多
This study focuses on the Kakobola region and its surroundings where cavities discovered in its basement may represent a major risk for the hydroelectric dam erected on the Lufuku River near the Kakobola city and the ...This study focuses on the Kakobola region and its surroundings where cavities discovered in its basement may represent a major risk for the hydroelectric dam erected on the Lufuku River near the Kakobola city and the civil engineering works in the study area. In order to deepen the studies related to this understudied region and provide decision-makers with information that will enable them to make the necessary and appropriate decisions regarding the development of this area, a study based on the analysis of geomagnetic data was carried out using certain methods revealing more shallow than deep structures, and others highlighting the limits of both shallower and deeper structures. Total magnetic anomalies and reduced to equator (RTE) magnetic anomalies were used to map the subsurface of the Kakobola region and its surroundings. In order to detect the edges of magnetized structures, the horizontal gradient magnitude (HGM), the analytic signal (AS), the horizontal gradient of tilt angle (HGTA), the tilt angle (TA), the theta map (TM), the enhanced total horizontal derivative of the tilt angle (ETHDR), the tilt angle of the horizontal gradient (TAHG), and the tilt angle of analytic signal (TAAS) were used. The study area is characterized by two areas of low values of magnetic anomalies and two other sources of high magnetic anomalies located in the bed and the neighborhood of the two major rivers in the region. The shallow sources of magnetic anomalies are lying in the bed and the vicinity of the same rivers in the study area. The magnetic sources in the study area are connected and almost linear. Several magnetic lineaments identified in this region by different methods present several preferential directions, but the most predominant directions are NE-SW, NW-SE, W-E and NE-SW.展开更多
The area covered by this study is the county of Kakobola and its surroundings. Previous studies show that those related to the study of depths by the gravity method, using other techniques, are not always carried out ...The area covered by this study is the county of Kakobola and its surroundings. Previous studies show that those related to the study of depths by the gravity method, using other techniques, are not always carried out until now. The main goal of this article is the gravimetric characterization of our area by other approach. The interest is not only to map the lineaments and to know their dip, but also to estimate the depths of these different anomalies. The methods used for this study are the first total horizontal derivative (FTHDT), tilt angle (TA), analytical signal (AS) and horizontal gradient magnitude (HGM). The processing of the complete Bouguer anomalies (CBA) data was done mainly through software. Data analysis using the semi-finished body depth method shows depths ranging from 7.49 m to 224.6 m. Data analysis using the AS method shows values ranging from 41.7 mGal/m to 510 mGal/m. The fractures and/or geological contacts in our study area show dips ranging from -73.73° to 68.16° and North-South orientation according to the tilt angle method. The FTHDT shows several lineaments, a NE oriented fracture of Kakobola and low dip values which suggest a tabular structure of the subsurface in our study area. According to the HGM, the study area shows several preferential directions of fractures and/or geological contacts whose the most frequent directions are the NNE-SSW and WNW.展开更多
文摘The aim of this study is to characterize the subsoil in the southern region of the North-Kivu province (DR Congo). Gravity and geomagnetic data were used in this study. Five different filters—the horizontal gradient magnitude, the analytic signal, the tilt derivative, the horizontal derivative of tilt derivative and the tilt angle of horizontal gradient—enabled us to delineate the gravity and magnetic anomaly sources present in the shallow subsurface of the study area. The plains of the Rutshuru territory are dominated by sources of weak gravity anomalies and sources of very weak magnetic anomalies located almost in the same places. The southern part of Rutshuru territory and a large part of Masisi territory are underlain by shallow sources of high gravity and magnetic anomalies. Gravity and magnetic anomaly sources are almost identical in the study area. The shallow sources of gravity and magnetic anomalies encountered in our study area are more or less linear and connected. The numerous gravity and magnetic lineaments present in our study region have three major directions: oriented East-West, North-South and North-East-South-West.
文摘This study focuses on the Kakobola region and its surroundings where cavities discovered in its basement may represent a major risk for the hydroelectric dam erected on the Lufuku River near the Kakobola city and the civil engineering works in the study area. In order to deepen the studies related to this understudied region and provide decision-makers with information that will enable them to make the necessary and appropriate decisions regarding the development of this area, a study based on the analysis of geomagnetic data was carried out using certain methods revealing more shallow than deep structures, and others highlighting the limits of both shallower and deeper structures. Total magnetic anomalies and reduced to equator (RTE) magnetic anomalies were used to map the subsurface of the Kakobola region and its surroundings. In order to detect the edges of magnetized structures, the horizontal gradient magnitude (HGM), the analytic signal (AS), the horizontal gradient of tilt angle (HGTA), the tilt angle (TA), the theta map (TM), the enhanced total horizontal derivative of the tilt angle (ETHDR), the tilt angle of the horizontal gradient (TAHG), and the tilt angle of analytic signal (TAAS) were used. The study area is characterized by two areas of low values of magnetic anomalies and two other sources of high magnetic anomalies located in the bed and the neighborhood of the two major rivers in the region. The shallow sources of magnetic anomalies are lying in the bed and the vicinity of the same rivers in the study area. The magnetic sources in the study area are connected and almost linear. Several magnetic lineaments identified in this region by different methods present several preferential directions, but the most predominant directions are NE-SW, NW-SE, W-E and NE-SW.
文摘The area covered by this study is the county of Kakobola and its surroundings. Previous studies show that those related to the study of depths by the gravity method, using other techniques, are not always carried out until now. The main goal of this article is the gravimetric characterization of our area by other approach. The interest is not only to map the lineaments and to know their dip, but also to estimate the depths of these different anomalies. The methods used for this study are the first total horizontal derivative (FTHDT), tilt angle (TA), analytical signal (AS) and horizontal gradient magnitude (HGM). The processing of the complete Bouguer anomalies (CBA) data was done mainly through software. Data analysis using the semi-finished body depth method shows depths ranging from 7.49 m to 224.6 m. Data analysis using the AS method shows values ranging from 41.7 mGal/m to 510 mGal/m. The fractures and/or geological contacts in our study area show dips ranging from -73.73° to 68.16° and North-South orientation according to the tilt angle method. The FTHDT shows several lineaments, a NE oriented fracture of Kakobola and low dip values which suggest a tabular structure of the subsurface in our study area. According to the HGM, the study area shows several preferential directions of fractures and/or geological contacts whose the most frequent directions are the NNE-SSW and WNW.
