During the 1906 earthquake, the greatest loss of life at any single location took place near the corner of Sixth and Howard. That intersection, like virtually all of the South of Market area, stands atop the 260 acres of swamplands that once fringed Mission Bay. When the earthquake’s shockwaves crashed into San Francisco at 7,000 miles an hour, the reclaimed land under the neighborhood’s hundreds of wooden buildings liquefied and subsided. Exactly how many structures collapsed will never be known, because raging fires soon left the entire area a charred wasteland, but probably dozens or more did. Among them were four large boarding houses that collapsed near Sixth and Howard, killing at least 300 people.
The 200 block of Shipley is just a few hundred yards away from Sixth and Howard. Like a few other South of Market streets, it bears eerie witness to the subsiding land that was responsible for so much death and devastation.
The red apartment building at number 274 Shipley offers a dramatic example of subsidence. Its former garages are five or six feet below street level: Only the tops of the garage doors are above the ground. The effect is surreal, as if the house were a toy building half-buried in a sandbox. When the buildings sank, they often also tilted. A resident in one of the apartments in 274 said his floor is considerably out of level. Many buildings in the area are visibly out of plumb with their neighbors.
This sunken house, and the roughly two dozen others like it on Clementina, Clara, Tehama, Natoma, Moss, Russ and other side streets, were all built after the 1906 quake. They ended up as semi-caves because of subsidence and subsequent grading. After the 1906 quake the marshy land in the area continued to subside, causing streets and houses to sink as much as five or six feet. In 1930 and again in 1950, the City raised the streets and utilities to grade, but it was too expensive to raise all the buildings, so many ended up half-buried.
The side streets themselves also bear witness to subsidence. The main streets, like Howard and Sixth and Folsom, were periodically raised to official grade, but the side streets were not raised as often. As a result, a number of them are significantly lower than the main streets. Moss and Natoma streets are so depressed they almost feel like they’re lowlands in the Sacramento River delta, with the main streets the dikes.
There used to be more half-buried houses scattered around this area, but the 1989 quake damaged a number of them so badly that they were torn down. The survivors are like old prizefighters — battered and bowed, but still standing.