oo4 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
EFFECTS OF THE EARTHQUAKE ON HOUSES IN SAN MATEO AND BURLINGAME. 
By Rosert ANDERSON. 
Immediately following the earthquake of April 18, 1906, a detailed study was made 
by the writer’ of over 1,000 houses in San Mateo County. This work was carried on 
under the direction of Dr. J. C. Branner, of Stanford University. The houses examined 
included all those in the town of San Mateo and on the hills west of it in Burlingame and 
San Mateo Heights, as well as many in Homestead, Belmont, San Carlos, and Redwood 
City. Examination was made of all details that could possibly give a clue to the char- 
acter of the earthquake shock, and its effects upon movable things. 
San Mateo is a mile west of San Francisco Bay, and about 3 miles northeast of the 
San Andreas fault along which the earthquake had its origin. All the houses included 
in this investigation lie between 1 mile and 4 miles in a northeast direction away from 
the nearest points along the fault. A range of hills from 500 to 700 feet high lies between 
the fault and the valley bordering the bay where San Mateo and Redwood City are situ- 
ated. The houses examined at Burlingame and San Mateo Heights stand on the north- 
east flank Of this range of foot-hills. It was hoped that the directions of the streets 
of San Mateo, parallel and at right angles to the fault, would throw some light upon the 
relations of location to the center of disturbance. 
CRITERIA. 
The following classes of evidence were examined, with especial regard to the direc- 
tion and relative force of the shock: 
1. The wreckage of brick, stone, and wooden buildings, the parting of walls, and 
displacement of parts. 
2. The cracking of foundations and the movement of houses on them. 
3. The cracking, crumbling, shifting, falling, jumping, and twisting of brick chimneys 
above and below roofs, as well as of cement, terra-cotta, and other chimneys. 
4. The cracking and falling of plaster and coatings of cement on the interior and 
exterior of buildings. 
The sliding, falling, and jumping of dishes, lamps, bric-i-brac, pictures, books, 
potted plants, and all such loose articles. 
6. The sliding, tipping, jumping, and turning of furniture, such as bureaus, tables, 
“ bookeases, beds, pianos, stoves, safes, machinery, and all other large mov- 
able articles. 
7. The falling, sliding, twisting, and jumping of tanks, towers, porches, pillars, 
underpinnings, gate-posts, mantelpieces, derricks, ete. 
8. The breaking and offsetting of pipes, bending of bolts, shifting of stove-pipes, 
bulging of windows with lead seams, and the raising and lowering of sliding 
windows. 
9. The shifting of loose piles of lumber, stove, and cord wood, and various materials, 
and the sliding of articles on rough and smooth surfaces. 
10. The swinging of hanging articles, pictures, lamps, pendulums, ete. 
11. The breaking of wire connections, such as telephone, telegraph, and light wires. 
12. The remaining in position of articles at liberty to fall in certain limited directions. 
13. The parting of ground at base of telegraph poles and cracking of ground elsewhere. 
14. The spilling and splashing of liquids. 
15. The feelings, experiences, and testimony of people. 
This paper gives only the general results of all the data, the more important facts 
alone being tabulated. | 
Or 

1 Valuable aid was received from P. C. Edwards, A. L. Motz, and A. F. Taggart, students of Stanford 
University. 
