François was in the office, working at his desk, that morning, when he heard a strange noise like kraft paper being torn behind him.
Then it was the rumbling of tanks passing by during a military parade...
...except that it was not a fourteenth of July in Paris, but an unusually cold winter day in Palo Alto. And there were no tanks on campus.
At the same time, everything around him began to sway weirdly.
Even though he was sitting on a swivel chair mounted on casters, this was startling.
Someone shouted down the hall: « Earthquake! »
Everybody dived under tables for cover, as instructed during earthquake preparedness training.
The noise, it turned out, was coming from the window panes being distorted and amplifying earth tremors going through the building structure.
The whole episode did not last more than half a minute.
Then all was eerily silent.
People reappeared and began to talk.
Judith: Anyone hurt? Beware of aftershocks.
After a few minutes no perceptible aftershock had occurred.
And the earthquake had not been powerful enough to do harm to persons, nor damage to buildings and properties.
The San Franscico region straddles the boundary between the Pacific and North American tectonic plates, along the so-called San Andreas fault.
The two plates move at a relative speed of about 4 centimeters per year, causing frequent earthquakes in the Bay Area and elsewhere in California.
The last two major ones were the San Francisco quake of April 1906 in northern California (magnitude 7.8), and the Fort Tejón quake of January 1857 in central and southern California (magnitude 7.9).
Since then decades elapsed without major quake. Consequently tectonic (as well as psychological) stress is building up. And -- as unbelievable as that might be -- a sudden readjustment could measure in meters, or more some people say!
All along the second half of the twentieth century, up until today, San Francisco has been waiting for « The Big One ».
A few days after the earthquake, François was chatting with Susie in front of her fireplace, in hand a glass of white wine through which danced the refractions of flames:
F.: Did you feel the earthquake the other day?
S.: Yes. I was in San Francisco that morning. I had been invited to a party the night before, and I was staying in a room on the fourteenth floor of a hotel downtown.
S.: When I woke up, with a headache, and went to the window, and saw the city covered with a white mantle, and the floor beneath my feet began swinging, I thought « Holy cow! We went overboard with boozing and smoking joints last night », and I went back to bed.
F.: When did you realise that it had indeed snowed in the city and that there was an earthquake?
S.: Only when the receptionist later told me « Happy white Christmas! » and thanked God that the building was earthquake-proof did I understand that what I had seen and felt was genuine and not a side effect of my hangover.
S.: Do you have earthquakes in France?
F.: The French Riviera is a mess from a geological point of view, but major plate movements happen mostly further east, in Italy, Greece, or Macedonia, and on the southern side of the Mediterranean. I only lived through a small one when I was a kid.
S.: So neither of us have been thru The Big One yet. Let's have another glass of wine to celebrate.
: For the last 10 000 years, the northwestern coast of the United States up to Vancouver has been regularly devastated by large earthquakes and tsunamis caused by the Cascadia subduction zone (the Pacific Juan de Fuca plate sliding under the North American plate). They happen on average every 243 years. Geologists have been able to establish - and Indian oral tradition to confirm - that the last occurrence took place in January 1700... (I don't know the standard deviation of the period.) More on this in