Malacandra.me

Earthquake!

I remember my first earthquake like it was yesterday, although it was over 25 years ago. I was born and raised in upstate New York and had never felt the earth so much as twitch, so when I was in a meeting room discussing a software project with my bosses and representatives of a potential business partner, I did not want to be the first one to dive under the heavy wooden conference table when the room started to shake. I was not alone in this: no one wanted to be the first person to show what I thought, given the circumstances, would have only been prudent concern for their lives. But the tremor was actually of short duration, and it turns out that it wasn't that powerful at all.  But I had nothing to compare it to, and it was pretty scary to me, this whole business of the freaking ground shaking me and everything that approximated human scale as if we were fleas on the back of a wet dog.

On the trip back to the office after the meeting, I was given some perspective by  seasoned California-native colleagues who could each recount stories of bigger and more striking temblors. I was pretty sure that if what I had just experienced was 'nothing much', I didn't particularly care to see a Big One.

Today, years later, I'm resigned to the fact that I probably will. 

I already have - kind of.  Over the next few years I had occasion to feel quite a few quakes of varying power (and distance).  Most of them were like that first one, fairly short and not causing any visible damage anywhere close to me.  They weren't common occurrances, but happened frequently enough that I recall waking up one morning to my room shaking, thinking "Oh, it's just an earthquake" and falling back to sleep. At some point I had apparently become a Californian. 

When I woke up later to another, stronger jolt - and realized "Dude, you're on the first floor of a 10 story hotel!", I took more appropriate steps - based on my best understanding at the time - by moving into a door-jam… preparing to exit the building after the shaking had subsided.  Which it did, again fairly soon.  There were a few more small quakes that day as I studied a programming course at UC Santa Cruz a week before Loma Prieta.  In retrospect, those were foreshocks. 

Loma Prieta, which was a 6.9 quake, was something else.  I felt it up in Sonoma County, 108 miles away from the epicenter, and it was a completely different experience. It didn't feel like something shaking - it felt like something rolling - it was a series of waves.  I could see lampposts swaying like they were bobbing on the surface of the ocean. It created a feeling in the pit of my gut that I'd just as soon never experience again. It was scary on a very visceral level. 

And we were over 100 miles away.  But we were in a valley that has soil that liquefies.  Because of soil that liquefies, some of the worst damage of the Loma Prieta earthquake was seen in landfill areas of San Francisco, many miles away from the center.  Because of the liquifaction properties of the soil that my city is built upon, back in 1906 the San Francisco Earthquake completely destroyed our downtown 50 miles away. 

As luck would have it, my home lies just a few blocks away from a Bay Area fault that is considered overdue to shake.  Currently, it's thought that the Rogers Creek Fault should have a quake of about 7.1 sometime quite soon. At right is a map of the area that they expect should be affected by a Rogers Creek Quake. You can click on it for a larger version. That little red pin near the top left?  That's me. In the "black zone". 

Here's another map of where the worst damage is likely to be, based on soil and proximity to the fault.  Once again, I'm at the little "A" marker. 

We're lucky in that we've got a house that was built when "they really knew how to build them". Stucco walls permeated with chicken wire. And we've taken the precautions that we've been told we ought to: our house is bolted down to its foundation. We've got most of our heavy furniture bolted to the walls.  And we keep a shed full of water, canned food, and other emergency supplies. We've networked with our neighbors about emergency preparedness.

While it's scary to contemplate a big earthquake here, we're fortunate because we live in a state where we have (and enforce) building codes and have a population and a civic infrastructure that expects this kind of thing to happen. Although we know that should disaster strike, we shouldn't expect to see much of an emergency assistance from a city or county that will have its hands full - so we have to have our own first aid materials and supplies.

Disasters can happen anywhere. Here in California they can take the form of earthquakes or wildfires or mudslides. Elsewhere they can be severe ice storms or hurricanes or tornadoes. Or floods.  Or droughts. 

The thing is that what we regard as normal life is very likely, at times, to be punctuated with events that are unpredictable in the particular, but very predictable in the aggregate. So learn what your local risks are, stock up and be prepared to whatever extent is possible!