css3 ripple loop

.circle {
  height:100px;
  width:100px;
  border-radius:50%;
  background-color:red;
  
  position:relative;
  top:100px;
  left:300px;
  
  -webkit-transition:height .25s ease, width .25s ease;
  transition:height .25s ease, width .25s ease;
  
  -webkit-transform:translate(-50%,-50%);
  transform:translate(-50%,-50%);
}

.circle:hover{
  height:150px;
  width:150px;
}

.circle:before,
.circle:after {
  content:'';
  display:block;
  position:absolute;
  top:0; right:0; bottom:0; left:0;
  border-radius:50%;
  border:1px solid red;
}

.circle:before {
  -webkit-animation: ripple 2s linear infinite;
  animation: ripple 2s linear infinite;
}
.circle:after {
  -webkit-animation: ripple 2s linear 1s infinite;
  animation: ripple 2s linear 1s infinite;
}

.circle:hover:before,
.circle:hover:after {
  -webkit-animation: none;
  animation: none;
}

@-webkit-keyframes ripple{
  0% {-webkit-transform:scale(1); }
  75% {-webkit-transform:scale(1.75); opacity:1;}
  100% {-webkit-transform:scale(2); opacity:0;}
}

@keyframes ripple{
  0% {transform:scale(1); }
  75% {transform:scale(1.75); opacity:1;}
  100% {transform:scale(2); opacity:0;}
}