168 The East Anglian Earthquake.
" In the first place, and as a general rule, it is worthy of
notice that the greater part, if not all, the cracks which have
opened in the ground, the upheavals of the surface, and even
the depressions which have been observed in some places,
have always taken place in the vicinity of rivers and estuaries
(marshes) or the sea,......and it may be set down as a
general rule that the buildings situated in the immediate
vicinity of these bodies of water suffered much more than
those further away."
Mr. H. J. Johnston-Lavis has also called attention to the
fact that during the earthquake at Ischia in 1883 " all the
houses situated on the brink of a valley where the tufa was
loose and incoherent, were in most cases quite destroyed from
the fissures of an incipient or complete landslip."72
To give one other example, the earthquake which occurred
in the West of England on October 6th, 1863, at Upton-on-
Severn was "most violent in situations bordering on the
river," and at Worcester, "in the streets nearest the river,
the tremor appeared to be the greatest." 73
With reference to the present earthquake there are
numerous records which show that the shock may have been
felt at many stations on account of their marginal situation.
Thus Mr. E. A. Fitch, of Maldon, referring to the River
Blackwater, described the effects " as though the shock
followed the water," whilst in London the movement was
especially distinct along the Strand, at Shadwell, and other
places bordering the River Thames.
The area of structural damage offers along its coast-line
nothing but alluvial flats and marshes, sloping very gradually
down to the sea and to the numerous creeks and estuaries,
thus rendering the physical features of this tract of country,
which is devoid of any distinct line of outcrop or escarp-
ment, most unfavourable for the observation of effects due to
marginal vibrations. An examination into the records from
the more distant places, where only the shock was felt,
reveals, however, a certain preponderance of stations along
lines of outcrop, and more especially along the escarpments
72 Brit. Assoc. Rep. Southport, 1883, p. 501.
73 ' Times,' Oct. 7th, 1803.