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      195                                   Wave                                                    and
                                          alate
      Earthquakes                           thinner  water  layer.   Uplifted Above   Level   Sea       a)  Configuration  of  sea  bottom  some  areas  out  of  the  sea  Plate  suddenly  unflexed



      of                                   causes  water  wave. Wave  is  low                         level.  d)
      Characteristics                         inundating  coastal  areas.   After  Earthquake   Below   eet   Ree   After  Earthquake   Downdropped as   Stress  Released      i  hquake.   earth:   lift   may   above  sea   region




                                           of  seafloor  during  earthquake  with  sea  bottom  in  shallow  area  channels  energy  into   violently)   b)   Dro,   d)   i   i  Rebound  during  earthquake   uplifts  coastal   flooding  region.







                                Wave   Earthquake   Focus   offset                                 Effects  of tilting  due  to  elastic  rebound  during   earthquake.  b)   plate   flexed   in

                                Generates   “Sy   Interaction   Earthquake    Earthquake           iltii   before   Bulge  during  earthquake.  downdropping  and

              Small  Amplitude   Ocean     7.8  cm)  in  deep  ocean.  b)   Before   a)   Before   c)   Stress   FIGURE   and
            ‘                              Tsunami.a)  Abrupt  amplitude  grows  considerably.  rapidly  (and  often   Uplifted as   Builds   7.9   land  surface   submerge  others.  c)





              a)   in  Deep                FIGURE





      |






          Effects  of ground  motion   a)  Wavefronts  of  waves.   Higher  seismic  station.  b)  S  and  surface  waves,  arriving  P-waves,  are  commonly   wave  energy  is   prolonging  the   earthquakes.   life   of   loss   and   cause   can   lines   install   to   is   and  electricity   gas   or  uplifts   down-   generating  water   a   These  ocean.   the   few   (a  amplitudes   water  shallow   uplifting.  down-   or   shallow   and   lowlands   sub-  during  flexed   r







          7.7  from  earthquake  waves  radiating  from  surface   initial   violent.  Surface   3.17),   (Fig.   shaking  during  large   damage   electrical   solution   the   faulting   7.8a),   cross   to   low   in   m  several   tilting,   marshes   turn   flooding  of  coastal   is   that   the   in   flexure,  raising   each   are   north-south,
          FIGURE   P,S.  and   focus  toward   amplitude   after  the   more   dispersed   violent   more   and  of  gas   effective   down   shut   earthquake   (Fig.   hours   have   to   cause   can   and   plate   plate   the   relaxes   the   seismometers,   directions




            Seismic   Station   fi   P                            often   breaking   low-cost   automatically   Sometimes   very   taking   “tidal   earthquake   bottom.   causes   earthquake   three   7.10).   to
          non           Focus                                     cause   and   abruptly   several   waves”)   grow   can   can   Uplift   sinking   lithospheric   of  bulging   The   vertical,
      Seismology   z   Z   f   Earthquake               Surface   Waves   (Dispersed)   earthquakes   from   the   A   burn.   that   shake.   seafloor   km/hr,   called   amplitudes   but   7.8b).   an   sea   or   involves  a   causes  strain   an  during   have   least   at   motion   (Fig.   responding



      Earthquake       As   i e   a   et  Seon   1  +  1  '  1  ‘  1  ‘  i  '  '  '  !   (   of  effects   Fires   itself.   cities   to   valves  cut-off   to   starts   the   of   1000   about   mistakenly   water,   (Fig.   during  rebound   surface   land  ground:  downdropping   case  special   Elastic   of  strain   7.9d).   (Fig.   typically   ground   (orthogonal).




                       *  ‘  *          ae                          shaking   of   sections   at   (sometimes   ocean   beaches   the   A   7.9c).   regions   Seismograms   of
               a   i   .   5                                      Secondary   portions   and   building   traveling   deep   of   dry   a,b).   (Fig.   rebound   stations   direction
      Chapter?                                                      the   switches   a   large   tsunamis   in   approaching   Elastic   dropping   into   7.9   coastal   another


                                         buryeys  punos             than   large   when   warps   wave   cm)   bays   (Fig.   duction   sudden   ing   Earthquake   Seismic   ferent   one   motions.
                                          Jo  epnyjdury
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