How Long Will You Need To Be Self-Sufficient?

Once an earthquake is over and the initial urgent matters like first aid and fire-fighting are handled, it will take time for outside help to arrive so you’ll be on your own for a while. That means keeping an emergency supply of things like food, water, fuel, batteries, and other consumables. How much you should store obviously depends on how long you’ll need to be self-sufficient, so we have to ask: How long will that be?

If you’re in a hurry and looking for quick answers here are my favorites:

  • Two weeks.
  • Whatever lets you sleep at night.

If you would like to delve a little deeper into this question, read on.

The real answer to our question is: “Nobody knows.” Anyone who gives you a glib reply like “two weeks” (including me) is not answering your question at all, because no reasonable person would predict that you will be without help for exactly 14 days. Natural disasters of any type are far too unpredictable for that. What you are actually getting is not an answer but a recommendation of what someone believes would be prudent for you to do, and like any recommendation it is based on certain assumptions. If you want to thoroughly understand what your level of safety is going to be, it helps to examine those assumptions in some detail.

In any earthquake large enough for this topic to even matter, there will be many people who need no help, and of the people who do need outside help some will have to wait much longer than others. There are a whole raft of things that influence your personal outcome: How strong the quake is, how close it is, how long it lasts, what kind of motion it generates, what kind of structure you are in, what affect it has on the infrastructure like roads and utilities, where you happen to be at the time, how well government agencies are organized to respond, and even sheer dumb luck. It’s clearly impossible to predict these, so we’re forced to deal with unknowns. There are no guarantees, but the goal is for you and your family to be reasonably prepared for the worst plausible event, so that you can sleep at night knowing that you’ve taken prudent precautions. (If you want absolute safety from earthquakes, move to Kansas — but talk to Dorothy first about other things that might happen there.)

The good news is that in spite of the uncertainties, the situation is not hopeless. We do have historical data and scientific knowledge that can provide us with useful estimates and guidelines. Organizations like the USGS have extensively studied the physics of earthquakes and their effects on structures, and they’ve created nice risk maps. The bottom line from them is that a major event will certainly not destroy the entire Bay Area (sorry, Hollywood), but it certainly will cause widespread destruction of buildings, kill and injure many people, and seriously disrupt just about everything. We cannot predict specific details, but we can get a pretty accurate broad picture.

We also have historical data on the effectiveness of emergency response, rescue, and relief efforts by our own government and other governments around the world. This data shows that in spite of the best intentions and very hard work on the part of everyone involved, such efforts often don’t go as well as we’d like, so prudence suggests that we not rely on perfect execution of disaster plans. To get a feel for this, let’s consider a few specific recent examples of sudden widespread disasters:

  • 1989, Loma Prieta earthquake: This was a serious if not crippling quake for the Bay Area, and it was a perfect example of how unpredictable these things can be: A single structural failure (the freeway collapse in Oakland) caused the total number of fatalities to be 3 times higher than it would otherwise have been.
  • 2005, Hurricane Katrina: This is both memorable and notable because even though forecasters provided plenty of advance warning, government emergency response fell far short of expectations and was heavily criticized. Some victims of the disaster were isolated for many days without any help at all, and even those who did make it to shelters often found themselves in appalling conditions. Even for aid groups that were well-organized, damage to roads and bridges caused significant delays. Although this was a hurricane, because of its geographical scope, damage to infrastructure, and number of people affected, it is arguably the best parallel to a big earthquake in recent US history.
  • 2008, Sichuan, China earthquake: China had considerable resources available, the social and political will to deploy them, and centuries more experience with organization and logistics than the US, yet because so much infrastructure had been damaged it still took many days for help to reach the victims.
  • 2011, Fukushima, Japan: Seismologists did not think an earthquake of that magnitude was possible in that location, but it happened anyway. Nobody expected a tsunami to be nearly that high, but it was. Their nuclear experts never expected an earthquake to trigger reactor meltdowns, but it did. And all this happened in Japan, which takes earthquakes very seriously and is one of the best-prepared and most technologically advanced countries on earth.

We can learn a few lessons from these and similar disasters, most of which are simply corollaries to Murphy’s Law:

  • In a disaster, things do not go according to plan.
  • Everything will take longer than you anticipate.
  • Expect to be surprised.

For a long time emergency agencies used to recommend that people be prepared with food and water for 3 days, but based on experiences like those described above (especially Katrina), many agencies are now moving toward recommending 2 weeks. This is why I say “two weeks” when pressed for a simple answer, but it would be even better to think about this stuff for yourself and decide what time period makes you comfortable. If you are very risk-averse and worry a lot, and you think that having a whole month of supplies would make you feel more secure, go for it. If the disaster turns out to be really bad then you’ll be prepared, and if it turns out to be not so bad you can share with your neighbors and be a hero. On the other hand if you feel that your own personal odds of being isolated for 2 weeks are just too small to worry about, and you are confident that 1 week of supplies is sufficient, then do that.

I can advise you and make suggestions, but ultimately it’s your family and you have to make the final call. Just as in an actual emergency, you’re on your own here. Consider the magnitude of damage that might occur in a major quake, the resources that would — and would not — be available (for example, San Jose has about 1 fire station per 32,000 residents), and the time it would take to mobilize those resources. Then pick a number and plan accordingly. If you can sleep at night, then you picked a good number.

One last factor to consider is that you don’t need to do everything at once. Let’s say you decide that you really want to be ready for 2 weeks, but that just seems overwhelming. Don’t panic or give up, just take it a piece at a time. Prepare now for 3 days, and in a few weeks or whenever you are able prepare for another few days, and then later for another few. You can also set priorities, such as storing food for 3 days but water for a week. Remember that something is better than nothing, and that even slow progress will let you reach your goal if that progress is steady.

Spend a few days thinking about how many days of supplies you want to store, at least to begin with, and next week we’ll start looking at ways to store the single most important item to have available after an earthquake: Water.