working try!

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
    <title>Easy earthquakes</title>
    <script src="https://d3js.org/d3.v3.min.js"></script>
    <script src="https://libs.cartocdn.com/cartodb.js/v2/cartodb.js"></script>
    <style type="text/css">
 
    body{
        background:black;
    }
    svg {
      width: 960px;
      height: 500px;
    }
    svg:active {
      cursor: move;
      cursor: -moz-grabbing;
      cursor: -webkit-grabbing;
    }
    circle {
      fill: none;
      stroke-width: 1.5px;
    }
    #first_layer path {
      fill-opacity:0.8;
      fill: none;
      stroke: white;
      stroke-width:0.5px;
      stroke-linecap: round;
      stroke-linejoin: round;
    }
 
    </style>
  </head>
  <body>
    <script type="text/javascript">
 
    var first_layer = 'live_map_views';

var pub = new cartodb.SQL({ user: 'staging20', format: 'json'});

// credit: https://html5doctor.com/finding-your-position-with-geolocation/
    function detectUserLocation(){
      if (navigator.geolocation) {
        var timeoutVal = 10 * 1000 * 1000;
        navigator.geolocation.watchPosition(
          mapToPosition, 
          alertError,
          { enableHighAccuracy: true, timeout: timeoutVal, maximumAge: 0 }
        );
      }
      else {
        alert("Geolocation is not supported by this browser");
      }
      
      function alertError(error) {
        var errors = { 
          1: 'Permission denied',
          2: 'Position unavailable',
          3: 'Request timeout'
        };
        startAnimation();
      }
    }

var color = d3.scale.log()
    .domain([1, 2, 3, 4])
    .range(["red", "yellow", "aqua", "green"]);

// Define our SVG element outside our SQL functions
    var svg = d3.select("body")
            .append("svg")
            .call(d3.behavior.zoom()
                .on("zoom", redraw))
            .append("g");
 
    // Our projection.
    var xy = d3.geo.mercator();
        xy.scale(1200);
        xy.center([-40,30]);
        xy.precision(0);
        
    svg.append("g").attr("id", "first_layer");
 
    var path = d3.geo.path();
    
    d3.json("https://staging20.cartodb.com/api/v2/sql?q=SELECT ST_Simplify(the_geom,0.01) as the_geom FROM live_map_views WHERE the_geom IS NOT NULL&format=geojson", function(collection) {
          svg.select("#first_layer")
            .selectAll("path")
              .data(collection.features)
            .enter().append("path")
            .attr("d", path.projection(xy));
      });
 
    var views;
    function startAnimation(){
      d3.json("https://staging20.cartodb.com/api/v2/sql?q=SELECT the_geom, category FROM axh_user_locations WHERE the_geom IS NOT NULL ORDER BY created_at ASC&format=geojson", function(collection) {
          views = collection.features;
          console.log(views)
          if (views.length > 0)  replay();
        });
    }
    var i = 0;
    function replay() {
      var c = views[i];
      svg.append("circle")
          .attr("cx", xy(c.geometry.coordinates)[0])
          .attr("cy", xy(c.geometry.coordinates)[1])
          .attr("r", 1)
          .style("fill", color(c.properties.category))
          .style("fill-opacity", 0.5)
          .style("stroke", color(c.properties.category))
          .style("stroke-opacity", 0.5)
        .transition()
          .duration(2000)
          .ease(Math.sqrt)
          .attr("r", 20)
          .style("fill-opacity", 1e-6)
          .style("stroke-opacity", 1e-6)
          .remove()
        setTimeout(replay, 200);
      i++;
      if (views.length==i) i = 0;
    }
 
    function redraw() {
      svg.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")");
    }
 
    </script>
  </body>
</html>

Modified http://d3js.org/d3.v3.min.js to a secure url

Modified http://libs.cartocdn.com/cartodb.js/v2/cartodb.js to a secure url

https://d3js.org/d3.v3.min.js

https://libs.cartocdn.com/cartodb.js/v2/cartodb.js