How to mark up an online event with Schema.org for Google?

Question

I have used the Event schema for describing an online event, but Google asks for location as a required property.

Which schema would you use? And if you used the Event schema, how would you set the location property?

<script type='application/ld+json'>
{
    "@context": "http://www.schema.org",
    "@type": "Event",
    "name": "This is the event name",
    "url": "http://example.com",
    "performer" : {
        "@type": "Person",
        "name" : "Daniel G.",
        "additionalName" : "Dani",
        "description": "This is my description"
    },
    "description": "This is the description of the event",
    "startDate": "2017-06-03T14:38:00+02:00",
    "endDate": "2017-06-03T15:08:00+02:00",
    "duration": "PT30M",
    "inLanguage": "es",
    "image" : "http://example.com/image.jpg",
    "offers": {
        "@type": "Offer",
        "price": 10,
        "availability" : "http://schema.org/InStock",
        "priceCurrency": "EUR",
        "url": "http://example.com"
    }
}
</script>

Answer 1

There is now additional markup available to describe online/offline events. For Event check out the new eventAttendanceMode property which accepts values from at least the following options (enumeration): OfflineEventAttendanceMode, OnlineEventAttendanceMode, MixedEventAttendanceMode.