I was still living in the Bay Area during the years 1986-1993. As a result, I got treated to the Loma Prieta quake of 1989, and the Oakland Hills firestorm of 1991.
I was just leaving work (in Emeryville) when the quake hit. I was sitting in my car, letting the engine warm a bit, when the entire car started bouncing up and down slightly. My first thought was "OK, who's jumping on my bumper?" When I looked up and found no one there, I realized it was a quake.
I didn't think much of it at first. However, just as my brain shifted into 'disregard, nothing big' mode, the main wavefront hit. The car bounced so violently that it was all I could do to just hold on to the wheel for dear life and pray that I wouldn't get overturned or something equally nasty. About that time, a bunch of windows on the factory building across the street blew out.
It was over nearly as fast as it had hit. I went back in, picked up a few bits and pieces that had fallen, and headed out to (of all things) do my laundry. The TV at the laundromat was on the local news channel, and that's when I learned just how severe the shaker had been (Bay Bridge and Cypress Freeway structures collapsed).
The image of cars trying (and failing) to stop on the Bay Bridge before going over that edge is, unfortunately, burned into my (very) permanent memory. I still get the heebie-jeebies about it to this day.
As for the Oakland Hills fire, we came very close to losing our house. I left late, after the rest of my family had already gone, and I clearly remember driving out past an entire hillside that once had a bunch of nice houses on it, but was now nothing but embers (I could literally feel the heat through the car door as I went past).
Thanks to the efforts of a very small and very brave group of volunteer firefighters, our area was one of the few that was spared. We didn't get so much as smoke damage. The rest of the area, however, was not so fortunate. It took two years before the place even started to look normal again.
Perhaps the most valuable lessons I took away from these incidents were to count your blessings, and NEVER take anything truly important to you for granted!
Earthquakes don't scare me, either. May be because I've lived in Florida all my life and haven't experienced one.
It's tornadoes that scare me the most. Little to no warning (besides violent weather), unpredictable and just focused destruction. Honestly, I've never seen one in real life, but there was one case when I was driving my mother and I to school (I attended the same school she taught at), and the weather was the worst I'd seen in a long time.
Well, it got extremely windy and, because it was pitch black dark (it was around 6:30 AM or so), I could barely see the road except for the reflective markers, which I had pretty much decided to follow. Sure enough, the reflective markers pretty much stopped dead, and I had to stop (luckily, no-one else was on the road).
We later found out that a tornado was reported to had barreled through that area only minutes before we drove by. It was so strong that it tore the reflective markers off of the road.
So, that's the closest I've been to seeing - or experiencing - a tornado.
And then the floor and walls started to shake!
The rest of the day was spent at the pool sharing conversations with other guests -- most of which began with someone asking "where were you when ..."
I don't worry about earthquakes either. Living on the east coast and mostly out of range of the nearest hazard (Charleston, SC) means that an earthquake is the least likely of the three.
I have to agree with most people and say that a tornado is far more intense and less predictable than a hurricane, which gives it a much greater "fear factor" (bad joke).
To answer the final question, natural disasters have never interfered with any of my plans to attend theme parks and/or events.
Fires are definitely scary... what's stupid is a lot of them are caused by people, whether it's cigarette butts, arson, or just plain negligence.
I know they're rare, but volcano eruptions are very scary... I was on a S.E. Asia trip when I was a kid and my family and I happened to be in the Philippines when Mt. Pinatubo erupted. It was a combination of an earthquake, the sun blocked out in the early afternoon (almost complete darkness), and then ash everywhere making everything grey.
As for theme parks, I've never been affected during a trip by any natural disaster. And in short, Tornadoes are the scariest.