Mr. Nyago Joseph (2012-2013Seismology Course) Department of Geological Survey and Mines, Uganda
1. Seismic observation in Uganda
In 1989, UNESCO and the International Programs in Physical Sciences (IPPS) donated four (4) Micro-earthquake (MEQ) 800 analogue paper seismographs. This made the Department Geological Survey and Mines through Uganda Seismological Network to revive earthquake monitoring after it was destroyed during political instabilities in 1979, and in 1990 three (3) of seismographs were installed at Entebbe, Hoima, and Kilembe. The stations form a rectangular network occupying the southern part of the country as shown in the Figure 1. In 1995, the Norwegian Seismic Array (NORSAR) donated and installed a fourth station at Dundu few kilometres from Entebbe. In 1996, a memorandum of understanding was signed between the government of Uganda and the University of California San Diego to install an IRIS global station at Kyahi-Mbarara. In 1999, the IPPS purchased three Orion Nanometrics digital seismograph stations to strengthen the MEQ-800
2. Monitoring equipment installed
Micro-earthquake (MEQ) 800 analogue seismograph
This is portable and wide range seismic recording equipment. At the station, the seismograph is connected to L-C4 short period vertical component seismometer for generating the seismic signal. The seismograph receives the signal from the sensor, amplifies and records it on paper wrapped on a rotating drum. The system is specifically designed for site location with an internal timing system that tags the time marks onto the signal. The seismograph is manually operated and the output paper record (seismogram) is interpreted and data retrieved is stored in the computer for further analysis.
Orion digital seismograph
This seismograph is a modern portable field seismic data logger from Nanometrics Inc., having 3 to 6 input channels. At each station, the seismograph is connected to an L4-3D three component short period seismometer which detects ground motion and records the signals it onto data cartridge. This seismograph has inbuilt GPS clock for providing time and it is capable of operating on different settings depending on the needs of the user. It can also be set according to suitable data acquisition modes either continuous or event detector trigger mode.
Kyahi global seismographic equipment
The equipment installed consists of a Quanterra, Q330 model digitizer, 3-component broadband, 3-component short period, and 3-component strong motion accelerometers installed in a borehole. It has a high resolution data acquisition recording system (DAS) designed to acquire data with minimal routine checkup. The DAS receives the analogue output from sensors and converts it to digital form. Workstation processor (computer) under the Solaris platform a version of UNIX operating system was installed to control the recording. The processor is connected to V-sat antenna for easy access of the data by Automatic data request manager at the University of California SanDiago (UCSD). The processor also monitors the state of health of the system and is capable of unpacking and copying data to magnetic tapes that are changed weekly and brought to Entebbe NDC.
Dundu seislog recording system
This a broadband station used to operate in near real time system, equipped with a CMG-40T three component broadband seismometer. It has a wide dynamic range recording system and the seismic signals from sensors are passed through a 24 bit digital seismic modulator and further transmitted by radio link to Seislog desktop receiving computer at the Entebbe National Data Centre. The radio link consists of a transmitter at Dundu and a receiver at the Entebbe NDC operating in Ultra High frequency band using a Yagi antenna.

3. Seismicity and Devastating Earthquake Events in Uganda
In Uganda, history of big earthquakes felt is associated with magnitudes in the range between 5.0 and 6.8. For construction and safety purposes, one should design earthquakes resistant structures for magnitude 7.0 and above and peak ground acceleration of 0.352g for the return period of 950 years. Uganda has severely experienced devastating earthquakes in the past as presented in the table below. Figure 1. Map showing seismicity of Uganda and vicinity in period 200 – 2010 Red star: Location of earthquake epicenters during the period 2000-2009 Black star: Location of earthquake epicenters in only 2010 Blue triangle: Broadband seismic stations Pink hexagon: Short period seismic stations