" In some places the railway track was curiously
distorted. "It was often displaced laterally, and sometimes alternately
depressed and elevated. Occasionally several lateral flexures of double
curvature and of great amount were exhibited. Many hundred yards of
track had been shoved bodily to the south eastward."
The ground was fissured at some places in the city to a depth of many
feet, and numerous "craterlets" were formed, from which sand was ejected
in considerable quantities. These are not uncommon phenomena, and were
due, no doubt, to the squirting of water out of saturated sandy layers
not far below the surface; these being squeezed between two less
pervious beds in the passage of the earthquake wave. The ejected
material in the Charleston earthquake was ordinary sand, such as
might exist in many districts which had been quite undisturbed by any
concussions of the earth.
Captain Dutton made a careful study of the observations collected
by himself and others concerning this earthquake, and came to the
conclusion that the Charleston wave traveled with unusual speed, for
its mean velocity was about 17,000 feet a second. The focus of the
disturbance was also ascertained. Apparently it was a double one, the
two centres being about thirteen miles apart, and the line joining
them running nearly the same distance to the west of Charleston. The
approximate depth of the principal focus is given as twelve miles,
with a possible error of less than two miles; that of the minor one as
roughly eight miles.
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