As said previously iOS7 is more strict with memory usage.
This behavior occurs in other browsers like Chrome, so when an app reach upper limit in memory usage, the crash appears.
I have isolated two test cases using only Gmaps javascript API and jQuery:
Testing with 100 markers: Everything it’s ok
http://jsfiddle.net/edfFq/6/embedded/result
Testing with 3000 markers: Crash occurs
http://jsfiddle.net/edfFq/7/embedded/result/
$(document).ready(function () {
var map;
var centerPosition = new google.maps.LatLng(40.747688, -74.004142);
var options = {
zoom: 2,
center: centerPosition,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map($('#map')[0], options);
for (var i=0;i<2800;i++){
var position = new google.maps.LatLng(40*Math.random(),-74*Math.random());
var marker = new google.maps.Marker({
position: position,
map: map
});
}
});
You can get the crash with a less number of markers if your map uses: labels, custom icons and clusters.