﻿Vol. 
  53-] 
  

  

  OF 
  AT7GXTST 
  1892 
  AND 
  NOVEMBER 
  1893. 
  

  

  163 
  

  

  Sound-Area. 
  — 
  The 
  earth-sound 
  was 
  heard 
  at 
  334 
  places, 
  at 
  all 
  but 
  

   5 
  of 
  which 
  the 
  shock 
  was 
  also 
  felt. 
  So 
  far 
  as 
  can 
  be 
  ascertained, 
  

   the 
  sound-area 
  coincided 
  nearly, 
  but 
  not 
  quite, 
  with 
  the 
  area 
  bounded 
  

   by 
  the 
  isoseismal 
  4 
  ; 
  but 
  the 
  number 
  of 
  places 
  near 
  the 
  boundary 
  is 
  

   too 
  small 
  to 
  allow 
  of 
  its 
  being- 
  laid 
  down 
  with 
  any 
  approach 
  to 
  

   accuracy. 
  Towards 
  the 
  north, 
  west, 
  and 
  south 
  the 
  two 
  curves 
  

   are 
  close 
  together 
  ; 
  towards 
  the 
  east 
  and 
  south-east 
  the 
  sound-curve 
  

   extends 
  a 
  few 
  miles 
  beyond 
  the 
  isoseismal. 
  

  

  At 
  53 
  places 
  it 
  is 
  expressly 
  stated 
  that 
  no 
  earth-sound 
  was 
  heard, 
  

   while 
  the 
  shock 
  was 
  distinctly 
  felt. 
  In 
  some 
  cases 
  these 
  places 
  

   are 
  near 
  the 
  boundary 
  of 
  the 
  sound-area 
  and 
  help 
  to 
  determine 
  its 
  

   position 
  ; 
  but 
  26 
  of 
  them 
  are 
  in 
  the 
  counties 
  of 
  Honmouth, 
  Somer- 
  

   set, 
  Gloucester, 
  and 
  Hereford. 
  It 
  is 
  not 
  at 
  all 
  an 
  uncommon 
  

   experience 
  to 
  find 
  the 
  earth-sound 
  unperceived 
  by 
  isolated 
  observers 
  

   at 
  places 
  well 
  within 
  the 
  isoseismal 
  5. 
  This 
  can 
  hardly 
  be 
  due 
  to 
  

   inattention 
  on 
  the 
  part 
  of 
  the 
  observers 
  ; 
  rather, 
  I 
  believe, 
  to 
  the 
  

   sounds 
  being 
  below 
  their 
  lower 
  limit 
  of 
  audibility. 
  

  

  Nature 
  of 
  the 
  Earthqualce-Sound. 
  — 
  Within 
  the 
  isoseismal 
  5 
  the 
  

   sound 
  is 
  generally 
  compared 
  to 
  the 
  passing 
  of 
  heavily-laden 
  waggons 
  

   or 
  traction-engines, 
  to 
  thunder, 
  etc. 
  The 
  sound 
  varied 
  in 
  pitch 
  and 
  

   character. 
  For 
  instance, 
  at 
  Lamphey 
  (near 
  Pembroke), 
  a 
  murmur- 
  

   ing 
  sound 
  resembling 
  that 
  of 
  sea-waves 
  at 
  a 
  distance 
  was 
  heard 
  

   for 
  3 
  seconds, 
  changing, 
  when 
  the 
  shock 
  was 
  strongest, 
  to 
  a 
  deep, 
  

   short, 
  heavy 
  boom 
  like 
  thunder, 
  and 
  continuing 
  after 
  the 
  shock 
  

   for 
  about 
  3 
  seconds 
  with 
  the 
  same 
  sound 
  as 
  at 
  first. 
  

  

  Between 
  the 
  isoseismal 
  lines 
  4 
  and 
  5, 
  the 
  slighter 
  sounds 
  which 
  

   gave 
  rise 
  to 
  these 
  variations 
  were 
  imperceptible 
  ; 
  the 
  sound 
  was 
  

   more 
  monotonous, 
  being 
  compared 
  most 
  frequently 
  to 
  the 
  low 
  roll 
  

   of 
  distant 
  thunder, 
  the 
  moaning 
  of 
  the 
  wind 
  or 
  of 
  sea-waves, 
  or 
  to 
  

   rain 
  falling 
  on 
  the 
  leaves 
  of 
  trees. 
  

  

  Time- 
  Relations 
  of 
  the 
  Sound 
  and 
  Shock. 
  — 
  In 
  the 
  following 
  Table 
  

   are 
  given 
  the 
  time-relations 
  of 
  the 
  beginning, 
  epoch 
  of 
  maximum 
  

   intensity, 
  and 
  end 
  of 
  the 
  sound 
  and 
  shock. 
  The 
  figures 
  show 
  the 
  

   number 
  of 
  places 
  in 
  different 
  districts 
  at 
  which 
  the 
  beginning, 
  etc., 
  

   of 
  the 
  sound 
  preceded 
  (p), 
  coincided 
  with 
  (c), 
  or 
  followed 
  (/), 
  the 
  

   beginning, 
  etc., 
  of 
  the 
  shock 
  : 
  — 
  

  

  

  Beginning. 
  

  

  Epoch 
  of 
  

   Maximum 
  

  

  Intensity. 
  

  

  

  End. 
  

  

  

  p. 
  

  

  31 
  

  

  18 
  

  

  19 
  

  

  7 
  

  

  9 
  

  

  84 
  

  

  c. 
  

  

  30 
  

   2 
  

   1 
  

   

   2 
  

  

  35 
  

  

  /. 
  

  

  4 
  

   

  

  2 
  

   

  

  7 
  

  

  13 
  

  

  P> 
  

  

  9 
  

   o 
  

   5 
  

   1 
  

   2 
  

  

  19 
  

  

  c. 
  

  

  41 
  

  

  6 
  

   6 
  

   

   3 
  

  

  56 
  

  

  /. 
  

  

  3 
  

   

   1 
  

   

   1 
  

  

  5 
  

  

  P- 
  

  

  5 
  

   2 
  

   3 
  

   2 
  

  

  2 
  

  

  14 
  

  

  c. 
  

  

  8 
  

   2 
  

   4 
  

   1 
  

   2 
  

  

  17 
  

  

  /. 
  

  

  o4 
  

   3 
  

   7 
  

   3 
  

   6 
  

  

  73 
  

  

  Pembrokeshire 
  

  

  Peso 
  of 
  Wales 
  

  

  Devon 
  and 
  Cornwall 
  

  

  Rest 
  of 
  England 
  

  

  Ireland 
  

  

  

  Totals 
  

  

  

  