The Boxing Day Tsunami that struck the Indian Ocean in 2004, caused by the Sumatra-Andaman Earthquake, was a defining global disaster of the 21st century ranking amongst the deadliest natural catastrophes in recent history due to its largescale destruction and loss of life. More than 220 000 people lost their lives across 14 countries. The 8.8 magnitude earthquake resulted in waves up to 30 m high and triggered earthquakes in Alaska and indirectly affecting Finland and Norway.
This year marks the 20th anniversary of this devastating event, prompting the timely theme of “Protecting our future by learning from the past” for this year’s World Tsunami Awareness Day on November 5th. This theme stems from “The lessons learned by the survivors, such as recognizing the warning signs of a tsunami and the importance of seeking high ground” (United Nations, 2024), and also aligns with the theme for International Day for Disaster Risk Reduction that falls on October 13th which focuses on the youth and future generations. While Umvoto doesn’t focus its work on tsunamis and the study thereof, this year’s World Tsunami Awareness Day theme aligns with the work we do do regarding disaster risk reduction and sustainable development. This work is crucial to our efforts in protecting communities and building resilience against the growing threats posed by natural and manmade disasters.
While the risk of tsunami’s along the South African coastline is low, it should not be completely ruled out. And communities living along the coast should learn the basic rules of thumb with regards to tsunami monitoring – for example, sudden retreating tides. Extreme but rare events could still potentially generate larger tsunami waves that could reach us, despite the broad shallow continental shelf surrounding the Cape Town area acting as a natural barrier thereby significantly dampening the city’s overall tsunami vulnerability. This geographical feature is an important part of the low tsunami risk assessment for this part of the South African coastline.
A greater risk for all regions are terrestrial earth movements. As a specialist hydrogeological consultancy, structural geology is an integral part of Umvoto’s skill and knowledge set. Disaster mitigation is an important consideration aspect for groundwater and construction projects in tectonically vulnerable zones, especially where the disturbances could trigger instability and subsequently earth movement or even localised earthquakes. For example, possible consequences of pumping water from aquifers are a loss of structural stability in the strata. Water acts as a matrix between the pores of the consolidated material making up aquifers and as an uncompressible medium in fractured systems. Specialist knowledge is required to identify inherent risks and responsibly manage wellfields.
Umvoto’s experience in geotechnical risk management extends beyond hydrogeology to construction, mining and other industrial processes. To learn more about the disaster risk reduction Umvoto does have experience in, head to our Disaster Risk Reduction and Geohazard Analysis page. And contact us to help you mitigate your risk to future disasters.
