Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-11-23
, u. S. Charts Future Earthquakes
BY FREDERIC ]. HASKIN.

Two new undertakings, the making
of airway maps and the location Of
regions susceptible Of being visited by
earthquakes, are being carried forward
by the United States Coast and Geo.
detic Survey. This branch of the Gov
eminent service, now under the De-
partment Of Commerce, Is one OF the
older agencies Of the Government and
has an enviable record Of technical and
scientific excellence.
In the past the work Of the Coast
and Geodetic Survey has been confined
| largely to the mapping Of the coastline
and of coastal waters. The branching
out into the mapping Of airwayS and
chronological surveys shows to what
extent Government services keep pace
with the demands of modern life.
No more fascinating work is done by
any Government agency than that per
| formed by the survey in connection
with the location of those sections Of
| the country where earthquakes may
occur. BY its very nature an earth
convulsion appeals to the human
imagination as something wholly I'M
| foreSeen, sudden and devastating. It Is
true that it is not possible to foretell
when an earthquake is going to occur
Such an earth seizure Is one Of those
| mysterious hCLo "a OOQ WHICH, COkIlC
without warning. However, the science
of the study Of the composition and
characteristics Of the earth has ad-
vAnced sufficiently far to enable 80 well
| equipped an organization as the Coast
and 0eodetic Survey to locate those
sections Of the earths surface most
likely to feel the effects Of seismic
disturbance.
! Scientific investigation has revealed
L HAN tA1P &tHA
| slipping of vast sections Of terrain
Shelving rock layers, impinging upon
earth material of different nature, are
likely locations. It will be noted that
the major earthquakes have occurred at
the coast. The San Francisco quake,
the tremendous Japanese disaster the
Italian, East and West Indian, and
indeed practically all Of the others have
occurred almost directly where the land
character Of the earth structure where
land meets water often 10 somewhat
abrupt, although not always. Where
there is an abrupt geological change,
| there Is reason to expect seismic dis
turbance. Not at any particular time.
OF course. Thousands Of years may
pass without . tremor, yet tomorrow
may bring . dislodGment which will
rae cities.
Possible Quake Regions Surveyed.
Congress has especially charged the
Coast and Geodetic Survey with dis
| covering all such likely earth faults on
| American territory. When major dis
| turbanceS have occurred q special study
| Is made Of the earth structure ct that
| place. The extent Of ground move
ment 10 carefully noted as well as the
| velocity Of the motion and the period of
I the vibration.
For example, If there has been q dis
turhance only slight In intensity at
some place which seems invitingly
! formed for tremors, subsequent QuakeS
may be expected. In other circum-
stances, 1t may be reasonably assumed
that the earth has slipped to o fairly
permanent anchorage, found fixed
place.
Such information is Of the first i'm
portance In the planning Of modern
human activities. In this age of sky
scrapers and other huge man-nade
structures, 1t Is well to know whether
q site selected is susceptible to seismic
| disturbance. Construction of bridges
and dams and the laying of water and
| other subterranean facilities may be
guided by information obtained by these
surveys. The planner of some large
construction enterprise viii be able, as