1906 Earthquake: Signal Corps

The 1906 earthquake severed all telephone and telegraph lines within San Francisco as well as those connecting the city to the outside world. Therefore, organization of virtually all relief efforts depended on the implementation of temporary communication lines. It was the responsibility of the Army’s Signal Corps to reestablish communications in the city as quickly as possible.
Downed power lines after the 1906 earthquake
The Olympic Club in April 1906. Communication lines throughout San Francisco were downed by the earthquake and subsequent fires.

Bob Bowen Collection


When the earthquake struck early on the morning of April 18, the U.S. Army Signal Corps at the Presidio consisted of Captain Leonard D. Wildman, three officers, and several privates. Wildman—an electrical engineer—and his men soon began the arduous process of stringing communication cables through a burning city filled with a desperate populace.

Despite the challenges, the Signal Corps successfully established a telegraph line between the Presidio and the city by ten o’clock in the morning. Additionally, they managed to keep the single line at the Postal Telegraph building open to Washington until it fell to the flames at three o’clock in the afternoon. The Signal Corps then ran a line from the headquarters at Fort Mason to the Ferry Building, where Western Union had access to an Oakland cable. In order to piece together a connection, electrical wires were cut from city light poles. Within one day, this line established direct communication between Army headquarters and the Secretary of War.

The Signal Corps’ role in the aftermath of the earthquake was far from over. In addition to mending lines cut during telephone and electric repair efforts, they also constantly reconnected telegraph lines disrupted by the dynamite squads. As the fire moved over Telegraph Hill, the Signal Corps quickly ran a line down scorched California Street. Despite the danger, it was necessary to stuff insulated wires into cable slots still hot from the blaze. Because of such daring efforts, the crucial communication channel in San Francisco was never broken for more than thirty minutes at a time.

Though additional men eventually arrived to relieve the Signal Corps, wire and supplies remained desperately short. Nevertheless, when the city was divided into military districts on April 22, the Signal Corps was able to connect the individual district headquarters with the Fort Mason department headquarters in just three hours. Eventually, the Signal Corps division grew to over 170 men stringing the lines that handled nearly two thousand messages per day. Over forty telegraph offices and seventy-nine phone offices were launched, providing communication between the seven relief districts and the mayor's office, the federal offices, and transportation points.

General Greely, who himself had been a highly decorated member of the Signal Corps, noted, "For three days, the only electrical communication in the downtown section was over the wires that Captain Wildman's men strung over the ruined walls through the heart of the burning district." The city remained dependent solely upon military telegraph lines until May 10th.

Signal Corps men repair lines after fire
Men from the Signal Corps repair lines in the smoldering ruins.

National Park Service, Golden Gate NRA


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"Great Work By Signal Corps; Lines Are Run Over Ruined Walls and Through Smoking Streets During Fire," San Francisco Chronicle, 3 May 1906.

Hansen, Gladys and Emmet Condon. Denial of Disaster, (San Francisco, Cameron and Company, 1989).

Strobridge, William. "Soldiers in the Streets, 1906," The Pacific Historian, Spring 1978 (vol. 22, no. 1).

"The Signal Corps and the San Francisco Earthquake and Fire," Presidio Ranger File.

Last updated: February 28, 2015

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