Is there any part of Taiwan where natural forces such as earthquakes and typhoons have a fairly minimal impact, with nothing more than an occasional heavy rain or some jostling?
As soon as my girlfriend learned that Taiwan was a hotspot for quakes she began to strongly prefer teaching in South Korea, and will likely continue to unless I can find a region of Taiwan that tends to remain fairly safe from natural disasters. Any ideas?
None. Ya know, there are earthquakes and floods in Korea too.
Just show her a profile of Kim Jong-Il, and remind her he’s a mere artillery shot from Seoul. That’ll keep her away from South Korea. At least Beijing and Taipei sometimes try to communicate.
Taichong’s probably safest from typhoons. I doubt anywhere on this island is safe from quakes. Then again, neither is the west coast of North America. (Or most other places, if you look far enough back in history.)
Far and away more important for safety: stay off scooters/ motorcycles and stay on public transport.
Coming from an also earthquake prone area, I am grateful that here you have a certain infraestructure in place to assist in case of disaster, plus a well organized army of volunteers from different charity organizations. No matter what happens, you will have your back covered by these people. Tell your girlfriend that bad things may happen anywhere, but here in Taiwan there is a cushion of help to soften the blow.
Plus, I’d rather have earthquakes, typhoons, SARS and bird/swine flu alone or combined any day rather than fearing for my life because of crime. Scooters I can try to avoid, and with a little practice, you too can learn to drive/cross the road like the locals. 
Tell your girlfriend not to worry. Taiwan is one of the safest places on earth. I’ve been here for almost a decade and the last thing on my mind is natural disasters.
I’d say Taoyuan County ranks up there, at least in terms of typhoons. But you pay for that by the cities being utter eyesores.
As for earthquakes, the Western coastlands usually feel the impact the least.
The eastern seaboard is usually the target of both earthquakes and typhoons.
Pretty much anywhere in the mountains is at risk for landslides (although the risk will depend on local topography), which can be triggered by both typhoons and earthquakes. For earthquakes, the farther you are from one of the red lines on the map below the better. Actually, Taipei is likely one of the safer cities.
But really, you’re much more likely to die in a car/scooter accident. Actually, it’d be interesting to see the numbers on people killed in typhoons/earthquakes/landslides vs. people killed in traffic…
Taoyuan is safe from Typhoons being too heavy, but it’s right on a fault line. However, the fault line appears to be a minor one, meaning it’s unlikely a true disaster will hit it anytime soon.
My mother-in-law’s sofa in Taipei NeiHu. Totally safe. Never ever anything has happened to me there. One time she even chased away the cops.
Given that Taiwan is the ROC may I suggets Guangzhou? They get the occasional typhoon and a little flooding but no earthquakes or volcanic activity and its nice and close to HK.
No natural dangers in Guangzhou, but lots of human dangers. 
Sanxia (Sansia), I’ve lived here for 13 years and I’m still alive and no wet feet … the occasional jolting, and some drizzle … and, it’s just 40 minutes from Taipei main train station …
Nature all around …
Who cares we are all going to die in 2012 anyway.
But for the next two years why don’t show her stats on rape, robbery and things like that.
For me Taiwan is one of the safest countries I have been in. And most probaby one of the safest in Asia.