San Jose, CA

The great San Jose earthquake of 1906 in today’s terms & what to consider

Vic Aquino
(image from Adobe Stock)

As each year goes by and major quakes occur around the world, it shouldn't be a surprise what's on the back of people’s minds in the Bay Area - “When will we get ours?”

115 years ago on April 18, 1906 at 5:12 AM the infamous 7.9 earthquake that lasted for less than a minute struck dead-aim at San Francisco and forever etched its mark on U.S. history.

Imagine a 7.9 now

From that 1906 quake, over 3,000 people perished of the 400,000 population around the San Francisco Bay Area. More than half (over 225,000) of the overall population were left homeless.

28,000 buildings were also destroyed. Three days of fires that followed the earthquake did a majority of the damage in San Francisco.

Almost a half-billion dollars in total damages occurred around the Bay Area from that day in 1906.

The 1906 quake line ran an incredible 300 miles along the well-known San Andreas fault from San Juan Bautista to Mendocino and was also felt in Oregon, Nevada and Southern California.

In comparison, the fault line spread of the 6.9 Loma Prieta quake in 1989 was only 25 miles, but exponentially, the ill-effects ran deeper.

Potential losses today if San Jose experienced the big one

In 1906 terms, the quake effect on a much sparser San Jose was nominal in comparison with 102 people dead (SJ population about 25,000 in 1906) and property damages estimated at $5 million then.

Extrapolate that in today’s terms in a much highly developed San Jose.

With general conservative math and assuming a population of 1 million in San Jose, an equivalent big quake could mean up to 1,000 deaths. This is seemingly realistic considering San Jose’s population density, which is not as high as in San Francisco.

Today, San Francisco has 18,832 people per square mile within its 47 square miles, whereas San Jose has 5,677 people per square mile within its 180 square miles (contemplating these density numbers for San Francisco alone in the next big one is frightening).

Of course, one key aspect we have now is much better building codes and regulation that greatly circumvents much higher loss of life and damage.

Let's consider San Jose’s trillion-dollar economy and infrastructure

In purely one-to-one dollar terms from 1906 to today and calculating 2600% inflation (as per the U.S. inflation calculator), we're roughly and conservatively looking at only about $150 million in losses today.

Surely, that's too low and it is. Consider it a reference point.

More realistically, we need to calculate losses based on a trillion dollar "net worth" for San Jose as a whole.

Without further confusing you with too much more math and numbers, let's just say San Jose's losses will be in the billions of dollars if the big quake hit now.

And the Bay Area loss overall if the worst happened today?

If in 1906 the overall monetary losses approached a half-billion dollars, using just a bit more basic math and deduction, say 10x, we could be looking into the low trillion dollars of losses.

OK, enough dizzying numbers. What to do next?

Apologies if it all starts to sound like a giant-numbers-death-and-doom-paranoia-scare tactic, but the moral here to consider is to start a plan and take slow and steady steps to prepare.

Short of being a doomsday prepper, there are fundamental things to do to get ready and to consider:

1 - Go kits: There are so many resources and places to get ready-made backpacks that contain first aid, tools, foods, clothing, communications and much more. You just have to scale it out to consider your loved ones such as for their cars or workplace.

2 - Your dwelling: Earthquake insurance is expensive; usually around 2x of your normal home insurance cost. Only 13% of California homeowners have it. When you consider those numbers over the years an earthquake doesn't happen, it's a significant sum. A consideration may be to retrofit. Licensed retrofit costs in San Jose can range from $20k to $100k depending on the method and size and location of your home. If you have a "soft story" or second story over a garage, it's a higher chance that portion of the home will collapse. If you're a renter, ask your landlord and consider renters' insurance.

3 - Cutoff from the necessities: Have some level of cash and food goods at home to cover your family for at least a week minimally. Have a safe for your important documents and other key items. Let your family know the plan to access and to communicate the basics in worse case scenarios. There are many more things to consider here and more than this article can cover in this format.

4 - Protection: This can be a hot subject, but protection can come in many forms and deterrents besides the obvious. It's closer to doomsday thinking and it requires that much more thought and consideration in higher density areas with a wider spectrum of people, especially extending this aspect to your family members.

5 - Others: If you've planned and thought through the above, you might begin to wonder, "what about my other loved ones and friends right outside my immediate orbit?" What's your responsibility to help or prepare them? What about neighbors and strangers you might run across? Imagine if the worst did happen and they needed help. Those serious preppers consider "10%" extra rationing in their case.

6 - The crowds: This gets even more into the doomsday prepper mindset, but it's good to know about. Beware of places where large crowds can gather. That may be the super market, a stadium, even schools. Often in worse case scenarios, desperation can more likely be there, especially if things stay offline for awhile and emergency services are overwhelmed.

These are some salient thoughts and levels of awareness to add onto the mental checklist of the heads of your household.

"The best preparation for tomorrow is doing your best today," a quote from H. Jackson Brown Jr.


Cited references:,,

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A 50+ year San Jose-native focusing on social awareness, social good, social impact and the hidden gems and treasures of the area. Freelance journalist & sports contributor to SB Nation & SF 49ers (@VicD_SJ on Twitter).

San Jose, CA

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