210 The Rast Anglian Earthquake.
No data have been available for determining the
maximum velocity of displacement.110
5. The earthquake occurred during a period of seismic
activity which will probably be found to have been
exceptionally great throughout the world.
6. No special meteorological conditions appear to have been
connected with the disturbance.
7. In general character the movement of the ground during
the present earthquake appears to have resembled that
which has been registered by seismographs in Japan.
8. The duration of the shaking cannot be ascertained with
precision, the estimate at different places varying
between two and thirty seconds.
9. At many places, and especially at those some distance
from the origin, two distinct series of vibrations were
110 According to the scale of the Swiss Seismological Commission, the
earthquake would be classed as a No. 8, or between 8 and 9. The Forel
scale is as follows :—
1. Very faint; recorded by a single seismometer; noticed only by
practised observers.
2. Registered on several seismometers of different construction; noticed
by a few persons at rest.
3. Duration or direction noted; felt by a number of persons at rest.
4. Felt by persons while moving; shaking of movable objects, doors,
windows; cracking of ceilings.
5. Felt by everyone ; furniture shaken, and some bells rung.
6. Sleepers awakened; general bell-ringing, clocks stopped, visible
swaying of trees ; some persons ran out of buildings.
7. Overturning of loose objects ; plaster falling, general fright; buildings
not seriously injured.
8. Chimneys falling ; walls cracked.
9. Partial or total destruction of buildings.
10. Great disasters ; overturning rocks, forming fissures and mountain-
slides.
M. Forel, who is one of the leading members of this Commission, writes
of a severe earthquake as " ce beau tremblement de terra." Seismologists
in this favoured country are fortunately not often required to pronounce
judgment upon such a calamity as that which forms the subject of our
report; but our earthquake will probably be looked upon by the Swiss
Commissioners as a fairly "good case," although not entitled to take a
front rank among such catastrophes.