Structural Study and its Effect on Thermal activities of Tulu Moye- Gedemsa Area
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Date
2007-07
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Addis Ababa Universty
Abstract
The Main Ethiopian Rift (MER) constitutes the northernmost part of the
East African Rift System (EARS), connecting the EARS with the Afar
triple junction and is an area characterized by active extensional
tectonics and associated volcanic activities.
The area of investigation, Tulu Moye, is situated in the Main Ethiopian
Rift (MER), northwest of Asela, close to the eastern margin of the rift. It is
a wide zone where tectonic and volcanic activities are concentrated. The
aim of this study is therefore, to show the relationships between
extensional structures (normal faults and tensional fissures) and
associated volcanic edifices with the aid of Geographic Information
System (GIS) for compilation of available geologic, structural and thermal
field investigations.
By integrating the Landsat images, aerial photographs and topo maps
together with the field data the lithology and structures of the study area
are mapped with better accuracy, minimum cost and shorter field
seasons.
Volcano – tectonic data showed a close relationship between dense
Quaternary faulting and associated eruptions. Volcanic activity is
becoming more recent and young towards the central part of the area
(west of the eastern escarpment).
Structurally the area is generally characterized by intense quaternary
faulting and fracturing. Three set of faults are mapped in the area
namely; NE – SW striking marginal normal faults, NW – SE to E – W
trending trans-rift faults and the youngest and active NNE – SSW to N –
S striking faults of the Wonji Fault Belt (WFB).
Almost flat foot wall and hanging wall tilted away from the fault plane is
the typical morphology obtained from morphology data collected using
Trimble GPS. An approximate E – W direction of extension is obtained
from kinematic data collected at two selected sites. Inventory of thermal vents in the area is made using Trimble GPS. The
relationship between these thermal sites and tectonics of the area is
clearly outlined. In such a way that, the vents follow the general NNE –
SSW trend of the intensively and densely populated faults of the Wonji
Fault Belt (WFB).
Description
Keywords
Tulu Moye- Gedemsa Area