var usgsEarthquakeUrl = 'http://earthquake.usgs.gov/fdsnws/event/1/query?minmagnitude=3&format=geojson';

    function GetMap() {
        var map = new Microsoft.Maps.Map('#myMap', {
            credentials: ‘AlXPdK-o4cuvCuOi_uBF6wUJBEbe8x8o0U00Uk579z2IQFfFGK1uu4tnpXIDhM58’
        });

        Microsoft.Maps.loadModule('Microsoft.Maps.GeoJson', function () {

            Microsoft.Maps.GeoJson.readFromUrl(usgsEarthquakeUrl,
                function (shapes) {
                    //Add the shape(s) to the map.
                    map.entities.push(shapes);
                }, 'callback');
        });
    }