|MadSci Network: Astronomy|
It rather depends on how long you want to stay on Venus. Over normal human timescales, rising diapirs won't be a problem. To see why, recall that diapirs are just rising blobs of hot rock. They rise because they are more bouyant than the surronding rock. But they are still rock passing through rock. And, as on Earth, this means they move slowly. Since we do not yet fully understand Venus's interior, I am unable to find exact times, but the time for rising through the crust is probably at least a few thousand to millions of years.
It's even better than that, though. Coronae are only found in certain areas of Venus, perhaps where the crust is thinnest. This means that if you built your base away from those places, you should be safe. It is rather like here on Earth: living in Colorado, I have little fear of volcanic activity. On the other hand, the people living in Hawaii are a bit more concerned than I.
The subject of living on Venus is a whole different matter, one I won't go into fully here. But you might want to worry about how you'll dig underground on Venus before your machines melt on the surface. Also, the absence of any kind of water is a hurdle. I'm also not sure that the interior temperature is much below the surface temperature. The temperature profiles for Venus's interior show temperature rising with depth, so you might just be making things worse by digging down. Nevertheless, you make an intriguing suggestion, one I shall have to think about more. The point about gravity is a strong case.
If you want to read a great book on Venus, I highly recommend David Grinspoon's Venus Revealed. It's the book I use whenever I have questions about Venus, and it is also very readable.
Try the links in the MadSci Library for more information on Astronomy.