Just another quick thought - he might be worried about what would happen if a natural disaster occurred and he wasn't with you (at school or at a friend's house etc). It might help to review with him how his school (if he's in school) keeps an emergency contact card on file, has a plan for what will happen in the event of an earthquake (schools here have children keep an emergency "kit" at school - gallon-size ziplock bag with emergency blanket, snack and comfort item), etc. Also for an earthquake you could go through with him the simple things you should do at home for shelter when an earthquake occurs - duck under a table or a doorway and wait for the shaking to stop.
You could also have him help you go through his room and make sure things like shelves, dressers etc are secured.
And one other thought - I think that it's tough for kids who are your ds' age to really grasp probability - so what may seem like a low enough risk to us as adults that we simply don't worry about it, might seem a lot more likely to happen to a child. You might do something like draw a timeline or pie chart or something that you could use to show him how *unlikely* a large earthquake is. You could also look at the USGS earthquake site online where there are maps of recent earthquakes around the world plotted by region and magnitude (size/color of dots on the map). Don't show him the website if you think it will be scary for him, but it might be a way to reassure him by showing him that earthquakes are literally happening almost all the time (and no one is getting hurt), yet big earthquakes are very rare.
polarbear
