_Maximum Velocity._--The most trustworthy measure of the maximum
velocity are those obtained from the projection of bodies. Mr. Oldham
selects the following as most deserving of notice:--At Goalpara, an
obelisk surmounting a tomb was broken off and thrown to one side,
giving a maximum velocity of not less than 11 feet per second. At
Gauhati, the coping of a small gate-pillar was shot off and fell at a
distance of 4 feet 4 inches from the centre of the pillar; in this
case the maximum velocity must have exceeded 8 feet per second. The
highest velocity, of more than 16 feet per second, was measured at
Rambrai, where a small group of monoliths were shot out of the ground,
one of them to a distance of 6-1/2 feet. Lastly, at Silchar, a bullet
was projected from the corner of a wooden post, acting as a rough form
of seismometer, from which a maximum velocity of at least 1-1/2 feet
per second was deduced.
_Maximum Acceleration._--Estimates of the maximum horizontal
acceleration were made from 28 overthrown pillars by means of
Professor West's formula (p. 184, footnote). The measures obtained at
the same place show some variation, but Mr. Oldham considers as fair
average values those of 14 feet per second per second at Goalpara, 12
at Gauhati, Shillong, and Sylhet, 10 at Cherrapunji, 9 at Dhubri, and
4 feet per second per second at Silchar.
Of the vertical component of the acceleration, not even the roughest
numerical estimate can be formed. We know, however, that at Shillong,
Gauhati, and indeed throughout the epicentral area, stones were
projected upwards, and this is evidence that the vertical component
was greater than that of gravity--namely, 32 feet per second per
second.
Violent as the shock was at the places just mentioned, it must have
been still greater in certain parts of the epicentral area. At Dilma,
in the Garo hills, the shock seems to have been strong enough to
disable men; and, in the neighbourhood of the faults that will be
described in a later section, forest trees were snapped in two.
Fortunately, as Mr. Oldham remarks, there were in these districts no
towns or populous settlements to feel the full power of the earthquake
to destroy.
Public-domain text, read in full here on John Shaqi.
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