I've done this question recently. *wanders off to get essay*
Ok, so...
Modify the event:
Prediction if possible. Things like hurricanes can be, but earthquakes can't, so but how, depending on the disaster, prediction can be effective.
Modify the vulnerability:
Protection schemes like warning systems, event-proof buildings, and for things like volcanoes you can dig diversion channels etc.
Modify the loss:
Evacuation schemes.
Hazard mapping.
Insurance.
Chuck in any case studies where necessary, including a hazard that was managed really well, and one that wasn't.
Then weigh up whether they can be managed, and if so what kind.
I got an A for my essay, so hope this is helpful