This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
This Major Research Instrumentation Recovery and Reinvestment (MRI-R2) Program grant supports acquisition of 20 dual-frequency GPS receivers and automatic weather stations (Met stations) that measure wind speed and direction, liquid precipitation, barometric pressure, temperature, and relative humidity. The new GPS/met stations will be installed by employees of the U.S. non-profit corporation UNAVCO, Inc. at selected sites across the African continent, with 15 to be collocated with existing seismic recorders that are a part of a previously NSF-funded seismic network on the African continent (AfricaArray; EAR - 0446647). All GPS and met data will ultimately be archived within the UNAVCO data management system and openly distributed via the Web. Operations and management responsibilities and costs will be distributed amongst AfricaArray station operators in host countries, plus the Council for Geoscience (South Africa), The University of the Witwatersrand (South Africa) and Penn State, following the model currently used to operate and maintain AfricaArray seismic stations. The AfricaArray geodetic network will enable unprecedented observations of African continent crustal deformation for research in tectonics with a particular interest in understanding the structure and mechanical properties and evolution of the continental rift basin in East Africa. Meteorological observations will dramatically expand current environmental observational capabilities across the continent and would support climatological and hydrological models. The PIs will engage underrepresented groups through existing university collaborations with African educational institutions and through opportunities for U.S. students at minority-serving institutions opportunities to do research in Africa. A broader goal of AfricaArray has been to couple training and research programs for building and maintaining a geoscientific workforce for Africa.
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UNAVCO, NSF’s Geodetic Facility for Solid Earth Science, secured this award to acquire high-precision GPS (Global Positioning System) equipment and weather stations to be installed with an existing seismometer network called AfricaArray, with the goal of continuously measuring the motion of the African continent and characterizing extension across the East Africa Rift zone that is splitting the continent in two and controlling the location and activity of famous volcanoes like Kilimanjaro. The continuous GPS (cGPS) and weather stations were added to 15 existing AfricaArray seismic stations and installed at 5 new locations across eastern, southern and western Africa. An additional four new instrument packages were provided by Penn State, to create a 24-station multidisciplinary community facility that now provides continuous high-quality location, timing and weather data sets, supported by technical staff in Africa. With millimeter precision, each cGPS stations measures the daily location of an antenna that is tightly coupled to the Earth, relative to a global reference frame of similar stations on all of the major tectonic plates. The stations also measure the water that is absorbed in the atmosphere, because the water vapor slows down the radio signals from GPS satellites. The weather stations measure wind speed and direction, rainfall and snowfall, barometric pressure, temperature, and relative humidity. The GPS/weather network provides the infrastructure necessary for focused studies of individual fault motions, volcano unrest, moisture that is absorbed in the atmosphere, ground deformation related to changes in the amount of surface water and ground water that are stored locally, and long term climate change. These are ongoing topics of research by the U.S. and international scientific community, of great interest both for scientific discovery and for better understanding of natural hazards such as earthquakes, volcanic eruptions, and drought. This award secured 20 GPS systems to be installed in Africa. Penn State University provided an additional four. The required 30% cost share was met by the three AfricaArray founding partners: Council for Geoscience, South Africa Geological Survey (Pretoria); University of the Witwatersrand (Johannesburg); and Pennsylvania State University (University Park). UNAVCO field engineers trained staff members in Africa for cGPS and weather station installation, operations, and maintenance while building the first six stations. The South African partners built out the rest of the network, with some support from UNAVCO for a handful of stations at the end of the project. This investment approximately doubles the GPS infrastructure in Africa, a critical step forward both for local regional studies and for strengthening the global data products that make possible millimeter-level observations with GPS anywhere in the world. Further training for data analysis by African scientists was provided in parallel with this project as part of the annual AfricaArray workshops.
