Trying to bind multiple InfoWindows to multiple Markers on a Google Map and failing

My project uses a JSON feed to grab info about earthquakes within a specified latitude and longitude boundary, essentially making a box. I take this info and turn all the results into markers on a Google map. I need each marker to also display some additional information, so I'm trying to use the built in InfoWindow objects such that when you click on a marker you open up the tooltip with some information associated with that marker. However I'm finding that no matter what marker I click, the same infowindow always comes up above the same marker of that group, and I believe it is always the last infowindow created in my loop. Here's the code.

$.getJSON(url, function(json) {
                    for(var i = 0; i < json.earthquakes.length; i++)
                    {
                        var pos = new google.maps.LatLng(json.earthquakes[i].lat, json.earthquakes[i].lng);
                        var info = json.earthquakes[i].lat + ", " + json.earthquakes[i].lng;
                        var marker = new google.maps.Marker({
                            map: map, 
                            position: pos,
                            title: json.earthquakes[i].eqid
                        })
                        var tooltip = new google.maps.InfoWindow({
                            content: info
                        })
                        google.maps.event.addListener(marker, 'click', function() {
                            tooltip.open(map, marker);
                        });
                        markers.push(marker);
                        tooltips.push(tooltip);
                    }               
                });

markers is an array for all the marker objects on the map and tooltips is another array for storing the infowindows objects. They're global.