DIRECTIONS OF VIBRATORY MOVEMENT. 355 
DAMAGES. 
The effects upon brick and stone buildings. —The region covered has only about 
25 buildings of brick and stone. In most cases, the damage done to these structures 
was far more severe than to those of wood. Usually a considerable part of some of the 
walls crumbled away, while the rest were left standing with large and small cracks in 
them. The tops of walls below the roofs usually suffered most, while lines of weakness 
in walls, caused by the presence of windows, arches, and other apertures, gave way to 
cracking more readily than other parts. A few brick buildings were totally demolished, 
as in the case of the long, brick, railroad warehouse at San Mateo. (See plate 98a.) 
The whole center of the picture to the right and left of the tower was occupied by the 
building, of which only the foundation remains. 
Some brick buildings, stoutly constructed or wedged in on business blocks among 
structures that acted as common supports, withstood the earthquake well, altho some 
portion was almost invariably damaged. The triangular gable ends of brick buildings 
rarely remained in place. The cracking in brick structures seldom past thru the brick 
themselves, but usually took place along lines of cementing. The very few stone build- 
ings in the vicinity of San Mateo were almost shaken to pieces. 
Wooden buildings. — In general, wooden structures suffered much less severely than 
those of brick or stone, tho the shock was felt just as heavily in them and the damage 
to loose articles was just as great. The buildings least damaged were small wooden 
houses, which were practically proof against the earthquake. 
Foundations. — The effect of the earthquake on foundations was of great importance, 
for the foundations were responsible for much of the damage to upper parts of buildings. 
With reference to this point, the buildings have been divided into 3 groups — those 
having foundations of wood, of concrete, or of brick. Wooden foundations are of various 
kinds, and the group includes all houses resting directly on the ground, or on wooden 
sills or wooden underpinning, even if the latter are supported on brick piers; it also 
includes all other buildings not having foundations of hard materials, such as concrete, 
brick, or stone. 
The foundations were examined for evidences of movements in various directions, 
and for the purpose of learning the relative amounts of cracking to which each was sub- 
jected. The accompanying table gives the results: 
Number of houses examined, with number of houses moved, and number of foundations cracked. 








BELMONT, BURLINGAME 
San Mareo., ReEDwoop. HOMESTEAD, AND SAN Tora. 
AND SANCARLOS.| Marro Hits. 
aac te Te i beceehe|-s =i] 2. lee 
n® ag So |no|oa3/8d | mb! os |/.9d| 2B] a 5]/sd]| 2d ou - z| oo | oS 
Character of. ae Ae aa 2 ey 23 ea Se lee 25 a ate z o 5 z ae ase 
foundation | §8 | 50 | Ug | 38] 28 32/158) 65 193/68) 50/382 55 09 |&°a| 33 i|sus 
me | mA | BS me ime | B65 mg ma] BS ms lea) Se) me | me | oe] BE | ess 
: Fe : cs cs os Po} ge [ALS 
Wood . 266 eee Oo woo ~of 00 2 “sh 38. 1 387 fT fad OF fale oe se 
Concrete . 176 51 43 7 TONE eee LAs 1 | 41 1 7 \*225 59 | 26 51 ao 
Brick . 160 51 63 8 S 1 160 Ks 4. 46_ 4 26— 230 58 26_ 94 41 
Total 602 | 149 | 106 | 78 | 33 TGs 2 5 | 95 6 | 33 | 842 | 190 | 23 | 145 
tt 













The total number of houses falling into these groups is 842. Of these 23 per cent 
moved on their foundations. In most cases the movement was not so great as to neces- 
sitate the returning of the house to its original position, but this had often to be done, 
since many houses were rendered unstable. The distance moved varied from less than 
0.25 inch to several inches, and in cases of special severity houses were thrown a foot or 
more off their underpinnings or foundations. Those on wooden foundations moved 
the least — 17 per cent in a total of 387 such houses. There were 225 houses on concrete 
