A 1960's aerial photo from the USGS showing a section of the San Andreas Fault that was moved 30 feet in the 1857 quake

Estimated at 7.9 on the Richter scale, the 1857 Ft. Tejon earthquake  ruptured the San Andreas Fault for a length of about 225 miles, starting near San Bernardino. Displacement along the fault was as much as 30 feet along certain sections, but much less closer to Los Angeles. The population of the area was a small fraction of what it is now, but dozens of accounts surfaced over the years. In 2006, Duncan Agnew at UC-San Diego compiled a collection of first-hand accounts. Some are quite memorable:

Augusta J. Crocheron (From Crocheron, 1885, pp. 371-372)

Can any one who has ever experienced an earthquake, overcome a dread of its recurrence;
or mistake the signs that are usually premonitors of its coming? One pleasant
morning I was searching through garden paths for roses for the breakfast table,
when the air seemed to hold still, not a breath stirring. I heard a far off smothered,
rumbling sound, that I scarcely noticed, for I thought I was growing dizzy, and not
understanding why I should feel so, I started for the house. As I stepped across a narrow
stream, the opposite bank seemed first to recede from me, then instantly to heave
upward against my feet. As this threw me from my equilibrium, the water emptied
out on either bank, and hearing an Indian’s voice in loud supplication, I turned and
saw our Lothario on his knees, the ground rising and falling in billows around him. At
the same instant I saw my parents and sisters clinging to large trees, whose branches
lashed the ground, birds flew irregularly through the air shrieking, horses screamed,
cattle fell bellowing on their knees, even the domestic feathered tribe were filled with
consternation. Voices of all creatures, the rattling of household articles, the cracking of
boards, the falling of bricks, the splashing of water in wells, the falling of rocks in the
mountains and the artillery-like voice of the earthquake, and even that awful sound of
the earth rending open—all at once, all within a few seconds, with the skies darkened
and the earth rising and falling beneath the feet—were the work of an earthquake. It
passed—we rejoined each other, thankful that life was spared, and looked around with
trembling, upon the scene, where utmost terror had reigned. Said father, it is scarcely
time to congratulate ourselves, another shock may occur in half an hour. In suspense
we waited, and it came. Then the skies cleared, the air moved with cool, swift wings,
the stream ran clear, and the earthquake’s spell had passed. When we ventured to
walk around at a little distance from the house, we found, about twenty rods away, a
rift in the solid ground, a foot wide, a hundred feet long, and so dark and deep, we
feared even to measure it.

Los Angeles Star January 10, 1857 p. 2

In some places the earth is represented as having undulated as a field of wheat moved by the wind. It
caused a general turn out, some rushing from their beds without stopping to dress.
An infinite variety of incidents are related of the effects of the shock, some amusing,
others astonishing—but all such as are likely to take place when people are tolerably
well frightened.

Los Angeles Star January 17, 1857 p. 2, col. 3-5

At the hotels, the breakfast tables were instantly deserted; people wildly rushed to the
streets, tripping and tumbling over each other in their hurry and dismay—in some
cases, blocking up the door, so as to prevent egress for the moment. Many, used to
indulge in a comfortable snooze of a morning, were unceremoniously turned out of
their comfortable quarters, in anticipation of having the roof about their ears before
they could make their exit. These took no thought of their toilet but gallantly gave
their linen to the breeze, in hopes of bringing up in safe quarters. One gentleman,
who, in his hurry, mistook his window for a door, was seen running along the roof of
an adobe building, thinking, should it fall, it was better to be on top of it, than it on
top of him. Another, enjoying the luxury of a bath, stood the rocking for some time,
but at last was compelled to evacuate the premises, and rush to the yard, where to
his horror a number of ladies had also sought refuge and were seeking consolation in
prayer. Whether from the shock to his feelings, or the shock of the earthquake, he
was immediately brought prone to the earth, when he managed to creep under cover,
unobserved,
Themost ludicrous scenes occurred on every hand—in some cases men falling down
in the streets on their knees, without well knowing why, perhaps because persons of a
devotional nature suddenly took to prayer in the streets, moved thereto by their fears
rather than their habits.