Shaken, and Stirred

Plumbing a millennia-old human relationship with seismicity

The world’s most famous earthquake occurred on the San Andreas Fault in northern California early in the morning of April 18, 1906, in two shocks separated by a pause and lasting between 45 and 60 seconds in all. The lower part of San Francisco’s City Hall collapsed almost instantaneously, as did many other buildings. But the fire that started after the earthquake had disabled the main water supply was what destroyed the city. Despite heroic efforts from firefighters and dynamiting of buildings to create fire-breaks, the fire burned for three days until it was at last deprived of fuel. By then it had devoured 508 blocks and more than 28,000 buildings, extending over 12.2 square kilometres (three quarters of the city and about eight times the area destroyed by the Great Fire of London in 1666), killed more than 3,000 people and cost at least $500 million. Combined with the earthquakes, it left 225,000 people—more than...