I didn't make it very clear, the bike comment was for a push along pack mule ala "Comrade Trahn on the Ho Chi Minh Trail, just a little west of the scenic Mu Gia pass photos" for the added equipment you would need for a 200mile trek

As a simple earthquake event, you're not alone, civilization hasn't collapsed and disaster relief will consist of authorities collecting resources to ensure survival of all and reopening access somehow. You might get helicoptered out of a stretch of road that's isolated by bridge collapse or landslide at either end. Or high-lined over the river or something. But there would be rescue. Eventually. Your long-term survival isn't completely dependent on your own resources though getting back to work on time won't be a factor for your rescuers.
You mostly need the ability to wait it out and deal with your family and others who might be stuck with you but who were dressed and supplied for the beach they were heading for on their vacation.

This situation appears to me to be one where you'll have to take up temporary residence wherever you are until the damage is repaired. That river looks to be a natural barrier with a capital BARRIER!

Maybe you should look at how many places could be used to buy a charter aircraft ride from where you might get stuck to where you need to go? I'd find all the small airports along the route and then make some inquiries as to whether a charter service or someone you know who has an airplane could be retained just in case. (if they are allowed in/out of the area)

Bear in mind that while there may be a canyon airstrip, mountain/canyon flying requires special skills and only a limited assortment of aircraft are compatible with those places.

I'm thinking that backtracking to Lewiston and catching a flight out is vastly preferable to trying to walk 200 miles. Even waiting a month for the flight would be a better choice than walking 200 miles. (Cost is not being considered in my discussion)

I agree with most of the poster here - the river is a truly significant barrier, and it might be worse after an earthquake and during the inevitable aftershocks. Most likely the wisest course will be to hunker down, using the abundant food and comfortable camping gear you can carry in the car. This goes double if you are not alone, and have to consider traveling over that terrain with your family.

If alone, consider carefully chosen, lightweight backpacking gear as the core of your outfit. Drive as far as you can in the car and then transition to a mountain/touring bike carrying your gear, which will probably weigh in the neighborhood of forty/fifty pounds including food for two weeks.

The bicycle vastly increases your range, if you can get it over the bridges and through or around the tunnels. It is no trick at all to travel 50-70 miles per day with a fully loaded touring bike, so it might be worthwhile to portage around obstacles in two or more stages if you will then reach clear roads or trails.

If that doesn't work, you are down to your backpacking outfit. Keep it small and as light as possible. Again, for a fit, experienced hiker, the distance you will need to trek is perfectly feasible. For sustenance,go with freeze dried stuff, especially since you have abundant water - MREs are way too heavy.

I would spend some time investigating trail networks in the area that might serve as alternatives if the roads are blocked. Google Earth is a fantastic resource here.

Overall, keep your options open. Stock your vehicle with versatile gear. Thee is always the possibility, I take it, that the focal point of the emergency might be at your "away"location and that you might be occupied there for a considerable time.

You might consider looking carefully at the geology of this region, especially with regard to the location of faults and any earthquake history. That information will help you refine possible scenarios.

Again, it is likely that your most reasonable option will be to shelter in place. Opening the transportation arteries will be a fairly high priority once rescue/recovery efforts are underway.

Whatever happened to "Beam me up, Scotty!"?

Dweste touched on it when he mentioned raft. Seems to me the only way out on your own is via river. White water rafting is something I've never felt the urge to try . . .

Other than that, find a good place for a shelter and set up camp.

This thread reminds me why I carry so much gear and extra food/water when I travel. You never really know where you will be when it hits the fan and you are on your own.

Geez, mate, that scenario is an old grizzly with a sore tooth, and you're asking us how to take its temperature (non-oral thermometer) and come back alive.

Well, maybe that's overstating it a bit.

200 miles is the worst-case scenario, but it's do-able for seasoned backpackers. If it's primarily on established roads, you can cover a good distance each day -- provided you have adequate food and footwear.

You'll probably have to carry extra water in places, unless you are very sure there's accessible water ahead. That adds to your pack weight, and reduces distance travelled per day.

Aside from standard backpacking gear, a few things come to mind.

- Information is going to be hard to come by, but if there is a radio station still transmitting in the area you'll want a small radio to tune in. Same with a cell phone -- if you can get a text out to let family know you're okay, that will relieve a great deal of worry.

- A portable solar option to charge spare batteries for lights and other items may be worthwhile.

- Any quake strong enough to take out tunnels will leave the mountainsides extremely unstable. You may need to cross a landslide or work around it. Some rock scrambling gear and the skill to use it might be a worthwhile option.

(Outside of the parameters posed, though, I have to say that if you are in a relatively stable zone with your vehicle and gear, I think the only real option is to stay put. Someone will be along in due course. Unless there's a town with a pub and air conditioning just over the rise ...)

I agree with unimogbert, an EQ isn't a scenario where you'll have to befriend hostile natives, learn a new language, join the local tribe, fight to the death with the largest in the dominant clan, and marry the native princess to get along and survive in a new world: your new world is defined by the bridges on either side of you, and whether there are points of civilization between those bridges. If you took the essential traveller advice, and left word with someone of where you were going and kept to your itinerary, unless that person is lost in the EQ, someone will be coming to get you, eventually. Alot of someones will also be doing aerial surveys of the roadway and bridges to assess damage and pick up those trapped by structural collapses, eventually. Communities that are cut off will want to be fed, eventually. County commissioners will want to make sure that these people get fed and rescued in this scenario, else they lose in the next election. Aerial rescuers will be looking for cars, bikes, people on foot - they'll be traversing the entire roadway. So stick to the roadway, and make yourself visible. Carry a map - if you can safely walk to the nearest village, or at least walk to see if the bridge is out before that village (most habitable locations tend to be at or near water for some reason), do it - you may see others who are trapped with you, or at least be able to wave at them on the other side of the chasm. If they're organized, they can get you across or point you to an alternate crossing. You won't be alone then.

A 200 mile march over unknown hostile is a fool's errand here. Bring water and food, shelter for warmth, comfortable boots, and changes of socks etc. It would be good to have something visible to lay in the road and mark your location to aerial surveyors, or your direction if you decide to take off and walk. Be prepared for the normal variances in weather and heat/cold. I think a bike would be extremely helpful in covering more road ground quickly - but every foot venturing off the road will decrease your chances of rescue. Make your attempt to reach the nearest civilization, but be prepared to wait.

Good point signaling ... My flight bag has a PLB, Laser flare and signal mirror. Good items for a long road trip.

If you want a true catastrophe scenario from earthquake think of all the trouble that a landslide damming that river could cause! Could create a northern Lake Powell for you to motorboat on :-)

The more I think about it, the more practical pulling a trailer with a jetboat filled with MREs starts to look....just in case.

Good point on the PLB - if you have a PLB or SPOT, activate it. It will fix your initial point of distress with responsible authorities. They may be abundantly busy with other rescues as well, but at least you're assured of being known and getting on their list.

Consider Murphy's law.

I'd wait a week or until I saw search helos before activating the PLB. Less chance of getting lost in the initial chaos. Also lets the authorities handle the more urgent cases first.