Daily independent. [volume] (Elko, Nev.) 188?-1915, 1909-03-13
SATURDAY. MARCH l3, 1909
The Phenomena OF Earthquakes Described


The phenomena of earthquakes are
interestingly described In Il recent pub
LEGATION of the photographic office. ut
Washington, u. c., in which the general
classes of seismic waves are defined,
and the manner of escape from danger
pointed out, In part it says:
Great multitudcs Of people live in
cities by the sell and are subjected to
the dangers arising from seismic sell
waves, and y0t, if Il place of refuge ex-
lists, they usually have ample time to
escape: and even the ships in the harhOr
will generally he safe il they promptly
put to sea on the first sign. after the
withdrawal Of the water, which always
indicates that the sea- bottom has sunk.
Thus, by the study of the laws of the
physical world AMI the diffusion of the
resulting useful knowledge, II great
measure of safety may be secured from
some of the most dreadful forces i'll
nature. and in the course of time the
interests of civilization may BE- enormo-
usly conserved.
"There are two general CLASSES of
seismic SEA waves. The first is due to
the sinking of the sea bottom, and is
characterized by IL withdrawal of the
water after the earthquake, to be
followed later by the return of Il great
wave; and the second is due TO the up
lift of the bottom. and is characterized
by the suddenrriSe of the SEA without
any previous withdrawal from the
shore. Most of the historical inunda-
tions of the sea have been due 10 waves
of the first class. The phenomena
usually noted are: First, an earth
quake: second, after Il short interval, the
sea is noticed to De Drainage lay
ing bare the bottom where il is or
dinarily deep enough for ship to anchor;
third, after III interval of an hour or
So, tho sea is seen TO be returning us a
mighty wave, washing everything be-
fore it. and thus carrying ships shore
ward and stranding them; fourth, hav-
ing once swept the shore, the sea again
withdraws and lays barr the harbor as
before, and after about the same inter
val again returns as Il second great
wave. This periodic movement of the
sea may be kept up for quite Il while,
and sometimes quiet is not restored for
IL day or two
Seismic sea waves of the second
ulass are produced by the uplift Of the
sea bottom into ridges or submarine
DiatcuuS and islands. In such cases the
water raises suddenly without previ-
0usly withdrawing from the shore.
1.-The lesson to be impressed upon
mariners in the light of these expert
Nnces is that the chances OF safety to
shipping are much Increased by pro-
cccding to sea, if practicable immedi
ttcly after the occurrence of an earth
quake; and this especially to be en-
joined if the water of the harbor is
found TO he draining away after the
shocks of earthquake have been felt
in the open ocean seismic sea waves are
not generally dangerous to vessels, be
cause their very great length and
moderate height gives them IL gentle
slope and their period j. very much
longer than that of ordinary SEA waves
by study of the charts of deep
sea sOundings throughout the world. it
can he told quite closely what the
expected state of seismic activity Of any
given region should he, for wherever
there are very deep oceanic troughs
situated adjacent tOmountainous ridges,
eliminating either below or above the
surface of the ocean, disturbances of the