Earthquake with Magnitude of 5.5ML Stirred Doctoral Research

What was regarded as the largest mine-related earthquake in the world rocked Orkney in the Northwest Province in 2014 and led to Mr Thando Nqasha being awarded a cum laude Master of Science degree in Land Surveying.

Nqasha’s thesis work – supervised by Dr Mayshree Singh – was titled: Investigation of the Directional Effect on Low Cost Houses due to the 2014 Orkney Earthquake.

‘UKZN is one of the leading research institutions in Africa with some of the best researchers,’ said Nqasha. ‘The Land Surveying degree offered there is accredited by the South African Geomatics Council (SAGC) and offered at only two institutions in the country. By pursuing a master’s degree, I wanted to get an opportunity to engage further in specialised fields related to Land Surveying such as GIS, satellite surveying, hydrographic surveying and photogrammetric surveying, that are critical to solving the problems facing society.’

Nqasha explained how he settled on his particular topic of research: ‘On 5 August, 2014, an earthquake of the magnitude 5.5ML occurred in Orkney in the Northwest province. It was the largest recorded mine-related earthquake in the world, causing major structural damage in the town and surrounding areas. More than 600 houses were damaged.

‘My research examined dominating factors that contributed to the damage caused to low-cost houses in Orkney and the surrounding areas. The primary factors that were investigated included the level of damage observed in the absence or presence of plaster and the effect of building orientation relative to earthquake propagation direction,’ said Nqasha.

‘Outcomes from this research can be used to improve the design and construction of these houses which will in future help to reduce the potential economic damage suffered by the people living in the dwellings.’

Previous studies in this area have been mainly laboratory-based owing to a lack of field data. ‘After this earthquake, the majority of the damaged houses were not repaired and accurate data with regards to structural damage could be obtained in the field,’ said Nqasha. ‘As a result, this is the first study in the world whereby the earthquake directional effect was investigated using field-based damage grade data in the analysis.’

The Orkney area is a highly active seismic region with some of the deepest mines in the world and is also surrounded by townships with low-cost houses. ‘This is certainly a highly volatile situation where the vulnerability of these houses is now significantly increased with the higher levels of seismicity,’ said Nqasha.

Recommendations from Nqasha’s study will help in improving the design, construction and location of low-cost houses situated in high seismically active regions. ‘This will save governments and other stakeholders investment in terms of rehabilitation and maintenance of low-cost housing and the protection of human life,’ he explained.

Nqasha plans to publish his research and expand on it at PhD level. ‘Many additional factors affect the level of structural damage observed during an earthquake, such as epicentral distance, local geological conditions, architecture and construction materials,’ he said. ‘For future research, I aim to develop a prediction model of expected structural damage due to an earthquake by simultaneously considering all the known factors that contribute to earthquake damage and investigating their relationships. This can be done using the Principal Component Analysis (PCA) or Cluster analysis tools.’

Nqasha thanked UKZN’s Discipline of Land Surveying for shaping his understanding of the surveying field and in particular his supervisor who supported him academically throughout his master’s. He also paid tribute to his mother, Ms Zikhona Nqasha, ‘whose love and guidance are with me in whatever I pursue’; and his friend, Mr Simphiwe Zulu, ‘who has been like my older brother throughout my varsity studies and supported me financially in my time of need and motivated me to keep going.’

Nqasha had some advice for his fellow graduates: ‘I would like to encourage surveying graduates to pursue research in surveying. With the advancement in technology such as satellite and drones, traditional surveying tasks are becoming obsolete. As a result, it becomes harder for surveying graduates to find jobs in industry. However, through research in the field one is able to find ways to adapt to the advancing technologies and use them with confidence to solve other real-world problems and create opportunities.

‘I came from a disadvantaged background where I did not have many role models to look up to,’ said Nqasha. ‘With the rise of social media, kids are more negatively influenced. I am hoping that my progress and hard work will inspire the younger generation to follow the same path as mine and have a positive influence on society.’

Words: Sally Frost

Photograph: Supplied