Field of Science

April 18, 1906: The Great San Francisco Earthquake

"San Andreas Fault
Moved its fingers
Through the ground
Terra cotta shattered
And the walls came
Tumbling down

O, promised land
O, wicked ground
Build a dream
Tear it down

O, promised land
What a wicked ground
Build a dream
Watch it all fall down"
"San Andreas Fault" sung by Natalie Merchant


One of the firsts to note something unusual where the sailors of the transport ship "Wellington" entering the bay in early morning of April 18. 1906, the captain reports that the ship "shivered and shook like a springless wagon on a corduroy road" even if the sea was as "smooth as glass".
At the shores of Ocean Beach the worker Clarence Judson was taking a swim in the sea when he was grabbed by a strong current and sucked into the deep - only with great effort he reached the coast:

"I tried to run to where my shoes, hat and bathrobe lay, but I guess I must have described all kinds of figures in the sand. I thought I was paralyzed. Then I thought of lightning, as the beach was full of phosphorescence. Every step I took left a brilliant iridescent streak. I jumped on my bathrobe to save me."

In Washington Street the police sergeant Jesse Cook observed a terrifying spectacle:

"The whole street was undulating. It was as if the waves of the ocean were coming toward me, billowing as they came..[]"
"Davis Street split right open in front of me, … A gaping trench. . . about six feet deep and half full of water suddenly yawned and sprang up on the sidewalk at the southeast corner while the walls of the building I had marked for my asylum began tottering. Before I could get into the shelter of the doorway those walls had actually fallen inward. But the stacked-up cases of produce that filled the place prevented them from wholly collapsing."

The Geography professor George Davidson awoke from the tumult coming from the street, he grabbed his wristwatch on the desk and noted the length of a first quake - 60 seconds- and the second - again 20 to 40 seconds - and the time that later will be the official date of the great earthquake of San Francisco: 5:12.

Many people were still asleep and killed in their beds, those who escaped gathered in the streets - despite the earthquake most of the city seemed still intact and surprisingly quiet.

In 1906 San Francisco was a great and ambitious, but also corrupt and infamous city with more than 400.000 inhabitants; it had experienced an incredible growth since 1848 thanks to the discovery of gold in the rivers of California. Now it was an important harbour to the Pacific Ocean and modern trade place, many shops sold the newest technologies in cameras and film equipment. The earthquake of San Francisco will become the first natural disaster of its magnitude to be so well documented by photography and motion picture footage (even in colour).
This growth and achievements were however possible only by cheap and fast construction methods and so most buildings in San Francisco were not exceptionally stable and made of wood.
San Francisco had burned to the ground six times in the past century and experienced stronger earthquakes in 1865 and 1868 when 30 people died. However the modern automatized fire department and equipment - horse driven and steam powered water pumps - was believed to be capable to fight every fire.
Fig.1. "Earthquakey Times", a caricature by Ed Jump of the October 8. 1865 earthquake in San Francisco. While he was working as a newspaper reporter in San Francisco, Mark Twain experienced the earthquake which he describes in his 1872 book "Roughing It."
"It was just after noon, on a bright October day. I was coming down Third Street. The only objects in motion anywhere . . . were a man in a buggy behind me, and a [horse-drawn] streetcar wending slowly up the cross street. . . . As I turned the corner, around a frame house, there was a great rattle and jar. . . . Before I could turn and seek the door, there came a terrific shock; the ground seemed to roll under me in waves, interrupted by a violent joggling up and down, and there was a heavy grinding noise as of brick houses rubbing together. I fell up against the frame house and hurt my elbow. . . A third and still severer shock came, and as I reeled about on the pavement trying to keep my footing, I saw a sight! The entire front of a tall fourstory brick building on Third Street sprung outward like a door and fell sprawling across the street, raising a great dust-like volume of smoke! And here came the buggy-overboard went the man, and in less time than I can tell it the vehicle was distributed in small fragments along three hundred yards of street. . . . The streetcar had stopped, the horses were rearing and plunging, the passengers were pouring out at both ends. . . . Every door, of every house, as far as the eye could reach, was vomiting a stream of human beings; and almost before one could execute a wink and begin another, there was a massed multitude of people stretching in endless procession down every street my position commanded. . . . For some days afterward, groups of eyeing and pointing men stood about many a building, looking at long zig-zag cracks that extended from the eaves to the ground..."

Police sergeant Jesse Cook was the first to report a fire at April 18. in a grocery in Clay Street, some hours later there where already fifty in the entire city. The fire fighters realized horrified that the water pipers in the underground were broken and the hydrants in the city useless. The firestorm rages in the city for three days and will be responsible of 90 percent of the 28.000 destroyed buildings.

The journalist Arnold Genthe is thrilled by the scenery and the devastation caused by the approaching fire, unfortunately he discovers that his camera was damaged during the quake.

"I found that my hand cameras had been so damaged by the falling plaster as to be rendered useless. I went to Montgomery Street to the shop of George Kahn, my dealer, and asked him to lend me a camera. "Take anything you want. This place is going to burn up anyway." I selected the best small camera, a 3A Kodak Special. I stuffed my pockets with films and started out...."
He will take some of the most famous photos in history.

Fig.2. "Looking Down Sacramento Street, San Francisco, April 18. 1906."

The owner of "Hotaling´s Whiskey" in Jackson Streets decides to remain and fight the flames - he pays 80 men to sprinkle 5.000 barrels of whisky with water pumped out from the sewer system. Later he will mock all those who claim that the earthquake was send by god by coining a new advertising slogan:

"If, as some say, God spanked the town, for being over frisky - why did He burn the churches down an save Hotaling´s Whiskey?"

Army troops were soon ordered into the city to help in the fire fighting and prevent panic and looting. The lack of water forced to desperate measures - by blasting of entire quarters to create firebreaks it was hoped to stop the flames, however many explosions ignited even more fires. Despite martial law was never proclaimed, the major authorized policeman and soldiers to shoot looting persons - "Obey orders or get shot" was the grim warning on some improvised signboards.
Guion Dewey, a businessman from Virginia, wandering onto the streets of downtown San Francisco minutes after the quake experienced the best and worst of human behavior, as he later reported in a letter to his mother:

"I saw innocent men shot down by the irresponsible militia. I walked four miles to have my jaw set. A stranger tried to make me accept a $10 gold piece. I was threatened with death for trying to help a small girl drag a trunk from a burning house, where her father and mother had been killed. A strange man gave me raw eggs and milk . . . (the first food I had had for twenty-two hours). I saw a soldier shoot a horse because its driver allowed it to drink at a fire hose which had burst. I had a Catholic priest kneel by me in the park as I lay on a bed of alfalfa hay, covered with a piece of carpet, and pray to the Holy Father for relief for my pain. . . . I saw a poor woman, barefoot, told to "Go to Hell and be glad for it" for asking for a glass of milk at a dairyman's wagon; she had in her arms a baby with its legs broken. I gave her a dollar and walked with her to the hospital. . . .I was pressed into service by an officer, who made me help to strike tents in front of the St. Francis Hotel, when the order was issued to dynamite all buildings in the vicinity to save the hotel. I like him, and hope to meet him again. When he saw I was hurt, which I had not told him, not yet having been bandaged, he took me to his own tent and gave me water and brandy and a clean handkerchief."

The earthquake and the firestorms killed estimated 3.000 to 4.000 people, destroyed 28.000 buildings and the infrastructure of the entire city - but in a surprisingly rush people begun planning and reconstruction work on their homes and life, three year later most of San Francisco was rebuild.

Seismology was still a young scientific discipline at the time of the earthquake in San Francisco, in part as a result of the lack of appropriate equipment like sensible tools to measure the tremors of earth - worldwide there were only 96 seismographs operating, none of these in California. In the aftermath of the disaster, only three days later, the Governor of California announced the formation of the State Earthquake Investigation Commission led by geologist Andrew C. Lawson of the University of California.
The commission concentrated their work on the San Andreas Rift, a local straight valley until them considered of minor interest and mapped only in short sections. For two years Lawson and his team followed the rift along ponds and streams and up and down poison oak-covered hills on foot and horseback, they recognized that the rift followed almost the entire coastline of California for more than 1.000 kilometres. During the April 18. earthquake nearly 480 kilometres of the Earth's surface along the today notorious known San Andreas fault line had ruptured displacing the ground horizontally instead of vertically, as geologists had previously believed to be the source of earthquakes.
The commission will locate the epicentre of the earthquake at the place of the greatest observed displacing on land - however today the epicentre is believed to be situated below the Pacific Ocean, in accordance to the seismic waves coming from the sea as observed by the first eyewitnesses.

Nevertheless this finding led team member Henry Fielding Reid, a geology professor at Johns Hopkins University in Maryland, to propose a new theory regarding the origin of earthquakes. Later dubbed the "theory of elastic rebound" Reid's hypothesis was to have a revolutionary impact on the young field of seismology.


MORRIS, C. (2006): The San Francisco Calamity by Earthquake and Fire. Librivox
SLAVICEK, L.C. (2008): The San Francisco Earthquake and Fire of 1906. Great Historic Disasters. Chelsea House Publishers: 128
STARR, J.D. (1907): The California Earthquake of 1906. A.M. Robertson, San Francisco

Online Resources:

USGS (2009): The Great 1906 San Francisco Earthquake.
(Accessed on 17.04.2011)

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