John Muir was born in Scotland in 1835, but is best remembered for his love of wilderness areas in North America, especially Yosemite Valley in the Sierra Nevada. In his book, The Yosemite, Muir describes--with his usual affection for anything wild--the great Owens Valley earthquake of 1872, which shook up the central part of the Sierra Nevada.
At half-past two o'clock of a moonlit morning in March, I was awakened by a tremendous earthquake, and though I had never before enjoyed a storm of this sort, the strange thrilling motion could not be mistaken, and I ran out of my cabin, both glad and frightened, shouting, "A noble earthquake! A noble earthquake!" feeling sure I was going to learn something.
The shocks were so violent and varied, and succeeded one another so closely, that I had to balance myself carefully in walking as if on the deck of a ship among waves, and it seemed impossible that the high cliffs of the Valley could escape being shattered. In particular, I feared that the sheer-fronted Sentinel Rock, towering above my cabin, would be shaken down, and I took shelter back of a large yellow pine, hoping that it might protect me from at least the smaller outbounding boulders.
For a minute or two the shocks became more and more violent--flashing horizontal thrusts mixed with a few twists and battering, explosive, upheaving jolts--as if Nature were wrecking her Yosemite temple, and getting ready to build a still better one.
... It was a calm moonlit night, and no sound was heard for the first minute or so [after the earthquake], save low, muffled, underground, bubbling rumblings, and the whispering and rustling of the agitated trees, as if Nature were holding her breath. Then, suddenly, out of the strange silence and strange motion there came a tremendous roar. The Eagle Rock on the south wall, about a half a mile up the Valley, gave way and I saw it falling in thousands of the great boulders I had so long been studying, pouring to the Valley floor in a free curve luminous from friction, making a terribly sublime spectacle--an arc of glowing, passionate fire, fifteen hundred feet span, as true in form and as serene in beauty as a rainbow in the midst of the stupendous, roaring rockstorm.
After the ground began to calm I ran across the meadow to the river to see in what direction it was flowing and was glad to find that down the Valley was still down.
This image shows a four-story brick building on the corner of Third and Mission streets in San Francisco following the 1865 earthquake. It appeared in The Daily Alta California, and is probably the very same building Twain describes as "sprung outward like a door" in the above quote.