360 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
predominating over the other. Grouping together all movements recorded as north- 
west and southwest and west, it is shown that 65.5 per cent of all the houses moving 
shifted in these directions. The second group of the table includes all movement in 
directions opposite to those of group 1 — that is northeast, east, and southeast. These 
make up 19 per cent more of the total. In the third group are included all those moving 
back and forth in the directions of groups 1 and 2, or partly in one main direction and 
partly opposite to the other main direction. These comprize 9 per cent. If, then, as 
the writer supposes, the west and east directions may be eliminated by being separated 
into their components, there will be 93.5 per cent of the total number that moved north- 
west, southwest, northeast, and southeast. 
Movement of chimneys. — The great majority of chimneys in the region under discus- 
sion are of brick. They are of many different shapes and sizes, in different positions 
on the roofs, of various materials, and are affected by structural variations and by age. 
They could not be expected to show perfect consistency in the direction of fall, but 
statistics were gathered in order to find out the tendency of the majority and their value 
as indicators of direction and intensity. 
In the following table the brick chimneys are grouped according to whether they 
fell in the direction of the slope of the roof on which they stood, obliquely, or at right 
angles to this; directly opposite to this, up the roof ; or according to whether they 
jumped. Those not falling form another group, of which a few shifted horizontally. 
The majority of streets on which the houses enumerated in this paper are situated, run 
in northwest and southeast, and southwest and northeast directions, so that the slopes 
of roofs are generally in those directions. More slope northwest and southeast than 
southwest and northeast. These directions of roof-slope make themselves apparent in 
the table, inasmuch as the slope of the roof exerts a marked control over the direction in 
which a chimney falls. 
Table showing the directions in which brick chimneys moved. 


















Chimneys which fell down the || Chimneys which fell in a direction oblique or opposite to the Total movement in all 
roof, t.e. with the roof-slope. roof-slope, and those shifting or jumping. directions. 
Number | Number P 
Direc- ree Per cent by ates falling | Number | Number Total Per cent by be ae Rtg 
tion, directions. |jobliquely| opposite | jumped, | shifted. . | directions. . ° 
fell. io Tork aae moved, directions, 
NW. 175 31 ( 8 4 10 5 27 LON 202 24 | 
SW. 121) og we ei 7 8 1 31 | 12 6 22 152 1g (52 
NE. 102 18 ( 42 19 3 AO i eee ee 26 LO a 19 128 15 { 24 
SE. 133 24 ‘are 14 a 2 2 25 9 | 158 19 | 
NNW. 1 0.25 Lb. Gh ecoeee La eee 16 6 i Wy 2 
WNW. 1 0.25 LD. Pik Sc tevecell ete ie eae 15 6 | 19 16 2 7 
WS Wee aac. eae oo | ee ata 1 | ee 6 2) 6 7 1 
SSW. 1 0.25\ , 13: ( Vigese scien lah Pa ei a ai 13 5°} 14 2 
SSE, SE eee | ares ao AIF i Meeps rer Rat heh ee | aire Dar 8 12 rte 15.5 12 1 
BSE de Ai hceare sd beens LO sell niceties, a delay Sete le 10 3 sos 10 Il. 
EN EY: il) See ee 8 De WN ete eeetse, pees okie 9 3 9 1 
NNE 1 0.25 12 1+ Pel es See ae ee 12 5 | 14 2 
Ww. 5 teers 21 1 ined SAG 23 ae ae 28 31 
b. 7 ea PD IR i ME Sire 1 i 12 4 | 19 2; 5 
N. é 1 8! gules uae tL eee ae ae 9 Sea 14 2 
S. 8 t dPeeant ao. Bieee fens Pie Meas 22 8.54 115 30 i\ 6 
Total 1560 2205 325. 431 59 270 
Southwest-northeast, 40 p. ct. Northwest-southeast, 19 p. et. Northwest-southeast, 43 p. ct. 
Northwest-southeast, 55 p. ct. Southwest-northeast, 22 p. et. Southwest-northeast 33 p. ct. 
: 60 per cent of all that fell. Fell in known directions . . . ee re eee oe eT 
2 22 per cent of all that fell. Caved away and fell in doubtful directions | ae eeOn 
3 3 per cent of all that fell, aa 
43 per cent of all that fell, Total fell wo cee ote Liste Tae a teehee) een Oe 922 
5 7 per cent of all that did not fall. Shifted’ «tae. lu ee ee oe eye cee Pee 9 
Stood without falling . . . . . . eee, 118 
Total number of chimneys . . .... , 3 1049 


