Geodesy & Geo-dynamic Research and Development


Overview

Geodesy is the science of mathematically determining the size, shape and position of the earth and the nature of the earth’s gravity field. Geodynamics is a subfield of geophysics dealing with dynamics of the Earth that applies physics, chemistry and mathematics to the understanding of how mantle, convection leads to plate tectonics and geologic phenomena such as seafloor speeding, mountain building, volcanoes, earthquakes, faulting and so on. The department provide PhD program in Geodesy and Geodynamics that covers mathematical geodesy, physical geodesy, satellite geode­sy, processing and analysis of measurements, and geo-informatics. Both the theoretical and practical aspects of geodesy are considered. In addition, it also prepares and offer training to the scientific society on the related science with the department goal and mission. Finally, the department works different scientific researches mainly focus on the thematic area of the department as well as the institute that have a great role to the economic and development of the country. The department work different projects in collaboration with the other government and non-governmental institute like Ethiopian Geospatial Information Agency and Ministry of Water, Irrigation and Energy etc as well as within the Ethiopian Space Science and Technology Institute like Remote Sensing Research and Development department and High Computing Directorate etc. Scientific activities of the department is mainly con­centrate on geodetic monitoring and analysis of global, regional and local geodynamic pheno­mena, precise positioning by combinations of various geodetic techniques, precise geoid de­termination, metrology and data processing. In the future, the department research area will be supported by an observatory for satellite geodesy and geodetic astronomy, a laboratory for geo-informatics, a laboratory for metrology in geodesy, and a reference geodynamic control station in Addis Ababa and Main Ethiopian Rift, inclu­ding a permanent GPS station and reference marks for absolute and relative gravity mea­surements (found in Institute of Geophysics, Space Science and Astronomy of Addis Ababa University).

 

Major activities

  • Doing research
  • Teaching and advising
  • Provide training

 

Project on Progress

Title: Ethiopian Height System Modernization Project
Principal Investigator: Dr. Tulu Besha and Mr. Girma

Description:

The Ethiopian Height System Modernization Project aims to improve current practice of height determination. Presently, Ethiopia uses a conventional method that requires physical connection to unevenly and scarcely distributed Blue Nile Leveling Network (survey control bench marks or monuments). Densification of leveling network requires an enormous capital investment and this has made the task of height determination an expensive business towards meeting the pressing socioeconomic demand for accurate height information. Therefore, it has now become authoritative to use modern satellite-based positioning, with detailed gravity data to determine height. The specific objective of this project is to adequately validate the accuracy of the geopotential height system (developed by Bedada, 2010) and recommend its operational level usage. The new height system will provide accurate height information in a cost effective manner/cost effectively/ during a real-time access to navigation satellites using user receives in the field. Height is determined for any isolated field points without tie to the passive leveling network.

Title: Space geodesy interferometric technique for safety monitoring of dams
Principal Investigator: Dr. Tulu Besha and MoWIE

Description:

The project aims to develop space-driven dam safety monitoring system. Application module will be developed to monitor the whole area around selected dams (Koka and Tendaho), including surrounding slopes, soil stabilization and compaction, working areas and auxiliary infrastructures. The monitoring tools use radar data from different satellites such as the European Remote Sensing (ERS), Envisat, Sentinel, ALOS-2, etc. Spaceborne Synthetic Aperture Radar Interferometry (InSAR) is a powerful tool for safety monitoring of hydro-dams and other earth dams.  The InSAR technology can detect ground motion with a precision up to 1 mm with high temporal and spatial resolution. With a freely available data, appropriate application tools could be adopted as long-term monitoring solution.

Title: Estimating crustal deformation in Arba Minch (Ethiopia) using InSAR and GPS
Principal Investigator: PhD student and Dr. Tulu Besha

Description:

The aim of this project is to study seismicty in the Arba Minch and its surroundings using two space geodetic techniques: Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS).  Analysis of these data sets will provide spatio-temporal patterns of crustal deformation, detection of seismicty as well as association of these signals with local geological structure. Results of the study are useful for seismic hazard mitigation.

Title: Monitoring and management of water resource  using space-driven products: a case of Ethiopia
Principal Investigator: Dr. Tulu Besha and MoWIE

Description:

The project aims to develop models and tools that can be used for monitoring and management of water resource. The specific purpose of the research is to monitor the variation of water at least over the last decade and forecast the quantity of available water within the entire region of Ethiopia. The models will determine the quantity of water by integrating earth observation satellites data (e.g. time-varying satellite gravity data, satellite rainfall estimates, microwave remote sensing satellites, navigation satellites) with in-situ meteorological datasets. This technique can be used to monitor the quantity of surface water and groundwater in near-real time and serve as a key tool for effective management of water resource.

Title: Exploring the causes of the expansion of the Lake Beseka
Principal Investigator: Dr. Takele Chekol, Dr. Tesfaye Demissie and Dr. Tulu Besha

Description:

The project aims to identify the main causes of the lake Beseka’s expansion using integrated space-based and in-situ geological and geophysical data. The lake has grown almost by 20 fold of its size in the late 1950s. The study will investigate the source of saline lake water and analyze its impact on the hydrology of the catchment and Awash river as well as on large farms such as sugar plantation. The research also predicts the lake’s future expansion based on local terrain and climate data and analyzes its potential impact on the environment and key economic infrastructure.

Title: The Dynamics of the Corbetti Volcanic Complex in the Main Ethiopian Rift (MER) and Its Impact on Hawassa and Shashemene Towns: Approaches from an integrated space based and in-situ investigations
Principal Investigator: Dr. Tesfaye Demissie, Dr. Takele Chekol and Dr. Tulu Besha

Description:

The purpose of this project is to study the dynamics of the seismically and volcanically active Corbetti Volcanic Complex, and its possible future geological hazardous impact in the surrounding nearby towns, including the densely populated Shashemene and Hawassa towns. Integrated space based and in-situ investigations will be used to study the composition of the volcano and its cyclic eruptive sequences.

Title: Space Geodesy Approach for Crustal Deformation and Thickness of the Dabbahu-Manda Hararo Rift (Southern Red Sea Propagator) in Central Afar, Afar Region, Ethiopia
Principal Investigator: Mr. Eyasu Leta and Dr. Tulu Besha

Description:

The DMH rift system is assisted by the up-welling magma which intrudes the more ductile lower lithosphere to erect dikes and feeding dikes that penetrate the stronger lithospheric layers. Furthermore, the crustal thickness of the Afar rift is attenuated due to the upwelling magma and also the rift is tectonically, volcanically and seismically active. It is an ideal locale to study the role of extension and magmatism as rifting progresses to seafloor spreading as well as crustal deformation due to the occurrence of earth quakes with the magnitude of more than 4.5 Richter scale in the area. The study area, in Central Afar, is located within the triple junction that divides the Nubian, Arabian and Somalian diverging plates, i.e., tectonically and volcanically active and structurally complex.

The main objective is to study in detail the spatial and temporal deformation of the rift, the maximum displacement of the surface as well as the crustal thickness and mapping the magmatic segment. To determine the amplitude displacement and movement of the crust, rely on interferometric synthetic aperture radar (InSAR), which, due to the dry and stable climate of Afar, is an efficient geodetic technique that enables us to measure surface displacements with a resolution of a few centimeters, over areas of hundreds of square kilometers (Simons and Rosen, 2007). To delineate the location and size of the up-welling magma and the crustal thickness across the rift using satellite and ground based gravity data.

 

Publication

Publication YearTitle and AuthorAccess
In pressPatterns of Lake Beseka Catchment Land use Dynamics: Implication on Soil Carbon and pH Properties. XX,pp XX-XX. In Melesse, A.M., Abtew, W., and Senay, G. (eds). Hydrology and Climate Variability: Monitoring, Modeling, Adaptation and Mitigation. Springer Geography. Springer, Cham.
Wubetu Anely, Tulu Besha Bedada, Berhan Gessesse
In pressEvaluation of Long-term Satellite-based Retrieved Precipitation Estimates and Spatio-temporal Rainfall Variability: The Case Study of Awash Basin, Ethiopia. In Melesse, A.M., Abtew, W., and Senay, G. (eds). Hydrology and Climate Variability: Monitoring, Modeling, Adaptation and Mitigation. Springer Geography. Springer, Cham.
Serwait Mengistu, Berhan Gessesse, Tulu Besha Bedada, Degefie Tibebe
In pressSpatio-temporal analysis of Agricultural Drought in Ethiopia using CORDEX Africa Climate Data. XX,pp XX-XX. In Melesse, A.M., Abtew, W., and Senay, G. (eds). Hydrology and Climate Variability: Monitoring, Modeling, Adaptation and Mitigation. Springer Geography. Springer, Cham.
Degefie Tibebe, Jemal Seid, Berhan Gessesse, Tulu Besha Bedada
2018Analyzing Spatial Distribution and Accessibility of Primary Schools in Bishoftu Town, Ethiopia. Geoinfor Geostat: An Overview,6(3), DOI: 10.4172/2327-4581.1000190.
Dejene, T.B., Tulu Besha Bedada, Leta Getahun Diriba
2018Regional recovery of gravity anomaly from the inversion of diagonal elements of GOCE gravitational tensor: A Case Study in Ethiopia, Artificial Satellites, journal of planetary geodesy, 53(2): 55-74.
Mehdi Eshagh, Andenet A. Gedamu, Tulu B. Bedada
2018Positional accuracy test of digital orthophoto mapping: case Bahir Dar, (2018). Nordic journal of surveying and real estate research, 13(1): 7–17.
Zinabu Getahun, Tulu Besha Bedada, Berhan Gessesse, and Martin Vermeer
2017Seismicity associated with magmatism, faulting and hydrothermal circulation at Aluto Volcano, Main Ethiopian Rift, Journal of Volcanology and Geothermal Research, DOI: 10.1016/j.jvolgeores.2017.04.003.
Wilks, Matt T; Kendall, JM; Nowacki, Andy J; Biggs, Juliet; Wookey, James; Birhanu, Yelebe; Ayele, Atalay ; Bedada, Tulu
2014Evaluation of EGM2008 by means of GPS Levelling Uganda, South African Journal of Geomatics, Vol.3, No.3.
Dianah Rose Abeho, Roger Hipkin, Bedada Besha Tulu
2010Interpretation of GRACE data of the Nile Basin using a groundwater recharge model, paper published on Journal of Hydrology and Earth System Sciences, 7, 4501-4533.
Bonsor HC, Mansour M, MacDonald AM, Hughes AG, Hipkin R, Bedada T.

 

Post graduate student

NameTitleResearch AreaContact Address
Daniel BahiruPhDPlate tectonics and ground deformation
Eshetu NegaPhDDetermination of reference frame
Andenet Ashagrie PhDGravity field, Moho and stress modeling
Andnet NigussiePhDCrustal deformation
Ephrem YalewPhDQuasi-geoid Modeling yalewephrem@yahoo.com
Tesfaye AbayPhDCrustal deformation and hydrological loading

 

Staff Profile

NameTitleResearch AreaContact Address
Dr. Tulu BeshaPhDEmail: tulub@essti.gov.et
tulubesha@yahoo.com
Eyasu LetaMScGravimetric and Geomagnetic methods, InSAR and GeodynamicsEmail: letaeyasu@gmail.com