The only comparison I can think of to picture 21 is pictures of Hiroshima and Nagasaki after the atomic bombings. Incredible.
Slightly related (but really good!) New Yorker article I was reading about earthquakes earlier. The essence of the article is that there's a fault line larger than the San Andreas fault that threatens the Pacific Northwest. I always read about impending natural disasters, and then immediately forget about them. Yellowstone is set to wipe most of us off the map any day now, isn't it?
Fascinating pictures. What jumps out is the amount of fire damage.
This is why it was called the "Great San Francisco Fire" for many years afterwards. Nobody wanted to bring mention to the earthquakes, and for the first half of the 1900's the descriptions mentioned a massive fire that burnt the place to the ground. In small fine print elsewhere it would mention the earthquake.