These were all done at night in the arches. Yes, even the second picture. The moon was still up, I used a 10 minute exposure, and the light from the moon lit up the rocks like it was daytime.
Arches is an amazing place. I love it there. If you are going, and want to know some great spots to hike or to take photos, let me know. I've been there a hundred times and know all the best places to go.