Seismic hazards of the world

This is the Global Sesimic Hazard Assessment Program’s global hazard map:

lilworld.jpg

Andrew Alden of About.com geology has produced a nice little resource by taking the high-resolution data freely available on the GSHAP website and breaking it down into a series of regional maps. Here’s the one for Africa:

africa.jpg


There is a 10% chance of the peak ground acceleration – the hardest shaking – exceeding the values plotted on this map in the next 50 years, For example, in the dark green areas there is a 10% chance that the peak ground acceleration will exceed 0.8 m/s2 (less than 10% of the acceleration due to gravity), which will certainly shake things up but is unlikely to cause major structural damage. So as you can see, outside of the Rift Valley Africa does not appear to be a hotbed of potentially dangerous seismic activity, although there are a couple of peaks elsewhere. I was wondering if the one in South Africa had anything to do with mine collapses, but in that case you’d think it would be closer to the Johannesburg gold fields. I’m also unsure about the peaks in Gabon and Ghana – the only recent geological activity in that region was Cretaceous rifting associated with the opening of the Atlantic.
Does anyone else have any ideas?

Categories: geohazards

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