South Africa
Geoscience for Infrastructure and Land Use
Understanding of seismic hazards and areas susceptible to dolomite-related ground movement across South Africa
Seismic Monitoring and Maintenance
The seismic monitoring and network maintenance project of the Council for Geoscience is derived from its mandate as determined by the Geoscience Amendment Act. The organisation has a statutory obligation to operate and maintain the national seismic network in order to report on instrumentally recorded earthquake occurrences in South Africa. The national network, the South African National Seismograph Network (SANSN), assumed network capability status in 1970 and has since been fulfilling the function of monitoring and reporting seismic activities. The monitoring functionality has (up to the present day) produced a significant seismological database of analog and digital waveform records comprising both current and historical earthquake records. Analysis of the recorded waveforms provides input into routine earthquake locations and fault plane solutions used to uncover the nature of the seismic source. The analysis produces a database (analysed waveforms and parametric data of seismic event locations and focal mechanisms) which is subsequently archived (together with raw waveforms) in digital format and maintained. The analysed database is shared internally for contributions to other Council for Geoscience initiatives such as geoscience mapping and geohazard assessments. The database may also be made available to local external stakeholders in the engineering, environmental and mining sectors and to international and regional organisations.
In addition to the SANSN, the Council for Geoscience operates and maintains three clusters of seismograph stations in the Central, West and Far West Rand and in the Klerksdorp–Orkney–Stilfontein–Hartebeesfontein (KOSH) region. The organisation also operates a collaborative network of eighteen (18) seismic stations deployed across the Bushveld Complex. The aim of these networks is to monitor and report on seismic activity in the mining regions. The Council for Geoscience has been maintaining the seismological databases resulting from seismic monitoring since the inception of the networks in 2010. This information is very useful in understanding the occurrences of seismic events in the mines and highlighting how they are related to mining and flooding in the mines. The recorded earthquakes can also provide valuable insight into causative structures and potential damage to modern infrastructure. The network in the Bushveld Complex is a collaboration linked to AfricaArray research initiatives.
Locations of stations making up the SANSN, the cluster networks and other collaborating networks.
Key Objectives:
- Providing seismic information for in-house research initiatives such as seismic hazard and tomographic studies focussing on understanding the subsurface and deep structures underlying South Africa. In effect, the tomographic studies can be coordinated to increase their relevance to the Council for Geoscience mapping programme.
- Providing seismic input in the ongoing effort of characterising seismogenic structures in view of further contributing to geohazard assessments.
- Facilitating the following:
- undertaking public awareness programmes.
- engagement with media and insurance enquiries and educational platforms within the country about the occurrence of earthquakes and their associated hazards.
- Facilitating collaborative projects (e.g. AfricaArray) with international and continental observatories as well as educational institutions and, in so doing, strategically assisting with the promotion of international diplomacy.
As indicated above, the outcome of the project is a seismological database comprising raw and analysed waveforms and parametric data of annual seismic location catalogues. The analysed database serves as input into seismic hazard and structural studies which, in turn, contribute to the geoscience mapping and geohazard initiatives of the Council for Geoscience. The analysed database is important in informing the public and other stakeholders about earthquake occurrences. In summary, the end products of this project (together with other internal initiatives) are immensely valuable to infrastructure planning and development in South Africa.
