It can be read on a number of levels. In the light of the recent events in China, we can't ignore its literal meaning - asking what kind of God could create a world so prone to such disasters.
I've always read it, though, metaphorically (maybe I'm reading into it) about those times when you realise the apparent certainties of life - those things you've built your life on - are not as secure or well-founded as was once imagined. I always thought about how God should have made the world and the Christian faith had he had a better mind - with no earthquakes and with clear, laid-down Christian dogmas and historically verifiable sacred texts. Yet, he didn't! Its all so much more vulnerable: