Integrated Remote Sensing and Geophysical Investigations of the Geodynamic Activities at Lake Magadi, Southern Kenyan Rift

被引:7
作者
Komolafe, Akinola Adesuji [1 ]
Kuria, Zacharia Njuguna [2 ]
Woldai, Tsehaie [3 ]
Noomen, Marleen [3 ]
Anifowose, Adeleye Yekini Biodun [1 ]
机构
[1] Fed Univ Technol Akure, Dept Remote Sensing & Geosci Informat Syst, PMB 704, Akure 340001, Ondo State, Nigeria
[2] Univ Nairobi, Dept Geol, Nairobi, Kenya
[3] Univ Twente, Int Inst Geoinformat Sci & Earth Observat ITC, NL-7500 AE Enschede, Netherlands
关键词
D O I
10.1155/2012/318301
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
The tectonic lineaments and thermal structure of Lake Magadi, southern Kenyan rift system, were investigated using ASTER data and geophysical methods. Five N-S faults close to known hot springs were identified for geoelectric ground investigation. Aeromagnetic data were employed to further probe faults at greater depths and determine the Curie-point depth. Results indicate a funnel-shaped fluid-filled (mostly saline hydrothermal) zone with relatively low resistivity values of less than 1 Omega-m, separated by resistive structures to the west and east, to a depth of 75m along the resistivity profiles. There was evidence of saline hydrothermal fluid flow toward the surface through the fault splays. The observed faults extend from the surface to a depth of 7.5 km and are probably the ones that bound the graben laterally. They serve as major conduits for the upward heat flux in the study area. The aeromagnetics spectral analysis also revealed heat source emplacement at a depth of about 12 km. The relative shallowness implies a high geothermal gradient evidenced in the surface manifestations of hot springs along the lake margins. Correlation of the heat source with the hypocenters showed that the seismogenetic zone exists directly above the magmatic intrusion, forming the commencement of geodynamic activities.
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页数:15
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