subroutine ping(s,nz,dtbuf,slim,wmin,pingdat,nping)

! Detect pings and make note of their start time, duration, and peak strength.

  real*4 s(nz)
  real*4 pingdat(3,100)
  logical inside

  nping=0
  peak=0.
  inside=.false.
  snrlim=10.0**(0.1*slim) - 1.0
  sdown=10.0*log10(0.25*snrlim+1.0)

  i0=0                                 !Silence compiler warnings.
  tstart=0.0
  do i=2,nz
     if(s(i).ge.slim .and. .not.inside) then
        i0=i
        tstart=i0*dtbuf
        inside=.true.
        peak=0.
     endif
     if(inside .and. s(i).gt.peak) then
        peak=s(i)
     endif
     if(inside .and. (s(i).lt.sdown .or. i.eq.nz)) then
        if(i.gt.i0) then
           if(dtbuf*(i-i0).ge.wmin) then
              if(nping.le.99) nping=nping+1
              pingdat(1,nping)=tstart
              pingdat(2,nping)=dtbuf*(i-i0)
              pingdat(3,nping)=peak
           endif
           inside=.false.
           peak=0.
        endif
     endif
  enddo

  return
end subroutine ping