﻿10 
  DR. 
  CHARLES 
  DAVISON 
  ON 
  THE 
  [Feb. 
  1 
  897, 
  

  

  7. 
  The 
  maps 
  do 
  not, 
  however, 
  give 
  a 
  complete 
  idea 
  of 
  the 
  relative 
  

   frequency 
  of 
  earthquakes 
  in 
  different 
  parts 
  of 
  the 
  district, 
  just 
  

   as 
  contour-lines 
  drawn 
  at 
  wide 
  intervals 
  do 
  not 
  determine 
  with 
  

   certainty 
  the 
  relative 
  heights 
  of 
  the 
  peaks 
  which 
  they 
  enclose. 
  The 
  

   preceding 
  Table 
  (p. 
  9) 
  supplements 
  the 
  maps 
  in 
  this 
  respect. 
  The 
  

   letters 
  A 
  to 
  P 
  correspond 
  to 
  the 
  rectangles 
  whose 
  centres 
  are 
  so 
  

   denoted 
  in 
  fig. 
  1 
  (p. 
  4). 
  The 
  figures 
  for 
  each 
  rectangle 
  indicate 
  the 
  

   percentage 
  of 
  the 
  whole 
  number 
  of 
  epicentres 
  in 
  the 
  Mino-Owari 
  

   district 
  which 
  lie 
  within 
  that 
  rectangle 
  for 
  the 
  month 
  or 
  period 
  

   mentioned. 
  

  

  8. 
  It 
  will 
  be 
  noticed 
  in 
  fig. 
  1 
  that 
  the 
  meizoseismal 
  area 
  is 
  

   forked. 
  The 
  more 
  important 
  branch 
  proceeds 
  towards 
  the 
  south, 
  

   while 
  the 
  fault- 
  scarp 
  apparently 
  follows 
  only 
  the 
  shorter 
  branch 
  

   to 
  the 
  south-east. 
  Prom 
  this 
  figure 
  alone 
  it 
  is 
  difficult 
  to 
  avoid 
  

   the 
  impression 
  that 
  a 
  considerable 
  displacement, 
  though 
  perhaps 
  not 
  

   superficially 
  visible, 
  must 
  have 
  taken 
  place 
  along 
  a 
  fault 
  passing 
  

   somewhere 
  near 
  the 
  axis 
  of 
  the 
  southern 
  branch, 
  and 
  this 
  impression 
  

   will 
  be 
  strengthened 
  by 
  a 
  glance 
  at 
  the 
  other 
  maps, 
  especially 
  those 
  

   in 
  figs. 
  2 
  to 
  6. 
  Without 
  having 
  any 
  geological 
  evidence 
  of 
  this 
  second 
  

   fault, 
  I 
  shall 
  assume 
  throughout 
  the 
  remainder 
  of 
  this 
  paper 
  that 
  it 
  

   does 
  exist. 
  Travelling 
  first 
  in 
  a 
  north-westerly 
  direction 
  from 
  the 
  

   sea, 
  it 
  probably 
  bends 
  towards 
  the 
  north 
  somewhere 
  near 
  the 
  point 
  

   M 
  (fig. 
  1). 
  But 
  whether 
  it 
  continues 
  to 
  the 
  north 
  joining 
  the 
  

   visible 
  fault 
  near 
  the 
  points 
  E 
  and 
  F 
  or 
  turns 
  again 
  to 
  the 
  north- 
  

   west 
  about 
  the 
  point 
  K, 
  that 
  is, 
  whether 
  it 
  is 
  a 
  branch-fault 
  or 
  one 
  

   of 
  a 
  system 
  of 
  faults, 
  is 
  not 
  clear 
  from 
  the 
  seismic 
  evidence. 
  The 
  

   isolated 
  curve 
  in 
  the 
  south-western 
  corner 
  of 
  fig. 
  2 
  would 
  seem 
  to 
  

   indicate 
  the 
  existence 
  of 
  another 
  fault 
  of 
  such 
  a 
  system, 
  but 
  the 
  

   foundation 
  for 
  the 
  inference 
  is 
  not 
  very 
  strong. 
  For 
  the 
  sake 
  

   of 
  clearness, 
  however, 
  I 
  will 
  give 
  provisionally 
  the 
  name 
  of 
  the 
  

   1 
  main 
  fault' 
  to 
  that 
  which 
  is 
  visible 
  on 
  the 
  surface, 
  and 
  of 
  

   the 
  ' 
  secondary 
  fault 
  ' 
  to 
  that 
  whose 
  existence 
  along 
  the 
  southern 
  

   branch 
  of 
  the 
  meizoseismal 
  area 
  is 
  inferred 
  from 
  the 
  testimony 
  of 
  

   the 
  earthquakes. 
  

  

  9. 
  The 
  central 
  points 
  C 
  and 
  D 
  (fig. 
  1), 
  and 
  possibly 
  also 
  E 
  and 
  F, 
  

   seem 
  to 
  be 
  connected 
  with 
  the 
  main 
  fault 
  ; 
  A 
  and 
  B 
  with 
  the 
  

   northern 
  end 
  of 
  the 
  fault-scarp 
  ; 
  G 
  and 
  H 
  with 
  its 
  southern 
  end 
  ; 
  

   and 
  L 
  and 
  N 
  with 
  a 
  probable 
  continuation 
  of 
  the 
  main 
  fault 
  to 
  the 
  

   south-east. 
  The 
  points 
  K, 
  M, 
  and 
  P 
  appear 
  to 
  be 
  related 
  to 
  the 
  

   secondary 
  fault. 
  

  

  If 
  we 
  measure 
  the 
  seismic 
  importance 
  of 
  a 
  rectangle 
  during 
  

   a 
  given 
  interval 
  by 
  the 
  number 
  of 
  epicentres 
  which 
  lie 
  within 
  it, 
  

   the 
  order 
  of 
  importance 
  of 
  the 
  lettered 
  rectangles 
  will 
  be 
  evident 
  

   from 
  Table 
  II., 
  the 
  corresponding 
  number 
  of 
  epicentres 
  being 
  

  

  