We strut and fret our hour upon a stage that’s anchored to a sleeping giant with a bad case of indigestion.

All may be well for a long time, but we forget the giant at our peril. When it shakes, our toys and lives may be shattered – or not. Hillsides may fall on us or slip into water which can then wash us away – or not.
We endure the uncertainty because there are many good things to be gained from this giant.
Indeed, taking calculated risks on when to stand our ground has worked out well for humanity down through the years, though always at great cost.
Who is at risk
Earthquakes dominate the headlines – rightfully so, as some of them are massively destructive and lethal – but travelers and anyone who invests in ownership or even rental of property are at risk from all sorts of earth movements.
The ground you’re living on or making money from may be slip-sliding away even as you read this:

It might suddenly sink:

Fly off (or move in, depending on your perspective):

Shake:

Or just change – forever:
Risk management
It seems like a no-brainer: Don’t build in dangerous areas! Retrofit your home if you live in a seismic risk area! And so forth.
In practice, though, it’s not so easy to just pack up and move, say, Guatemala City or Tacoma.
Retrofitting becomes harder to sell as time passes without major earthquakes. When tougher seismic codes are being challenged in such known hazard areas as the New Madrid Seismic Zone and New Zealand, what chance is there to push such things in less well-known zones, for example, Boston and the other Northeastern US areas that face the same level of seismic risk as San Francisco?
And you just can’t shut down transport when something like this happens (warning: a cuss word at around 1:30):
You can, however, learn about the geology where you will be living and working or traveling through, and try to understand the risks you may encounter there: earthquakes along the Ring of Fire or other areas; sinkholes in karst country; lahars in volcano country (these mudslides can and do happen even when the volcano hasn’t erupted in a long time); landslides in or near hilly terrain; and so forth.
It may even be possible soon to identify risk areas before the train rumbles past that vulnerable hillside.
Or you can just convict and imprison experts for failing to predict the unpredictable.
When to act
Timing is tricky when it involves the Earth.
Our planet operates on a long time scale that’s difficult for most of us to visualize – this complicates the job scientists have in explaining things to lay people and emergency planners.
It also allows people, unaware of the risks, to establish communities in dangerous areas in between disasters.
Another problem is limited data. Meteorologists today have a huge database to work with, almost in real time. Geologists are not so lucky.
Much of Earth’s activity happens out of sight, miles beneath the surface. The instrumentation to measure what’s going on down there has only been around for several decades, a mere blink in the geologic time scale.
Certainly the time to act is before disaster strikes, but it can sometimes be expensive and difficult to prepare for disaster. At other times, it can be very simple.
Generally it’s a complex matter, as shown by this event in California a few days ago.
According to local news reports, someone left a garden hose on too long, and the water caused a landslide that blocked the Pacific Coast Highway. The hose could simply have been turned off earlier, but what caused the conjunction of dwellings and major highway in such a vulnerable region in the first place? What can be done to avoid such events in the future?
These are very difficult questions that can be addressed only by many people who are working together in common interest.

In other words, the answers will not be forthcoming any time soon.
In the meantime, manage your own risks as best you can – with education (government geologist offices have abundant resources available) and preparation (an emergency kit and awareness of the hazards).
If you’re so inclined, get involved in efforts to upgrade codes or otherwise spread the words about risks in your area.
At the very least, don’t wait for it to happen: plan ahead. For example, what would you do, in real time, if you were in one of the cars in this WSDOT simulation video?
Good luck, and stay safe out there!
Further Reading:
This Dynamic Earth, United States Geological Survey
Real-time earthquake map (and links to all things earthquake), USGS
The Landslide Blog, Dave Petley and the American Geophysical Union.
“Judgment of L’Aquila: The Liability of Science and Civil Protection,” John Incorvati (In Italian – I used a free online machine translator to read it.)
Suggestions welcome!