These are quad video taken from the Sakurajima live webcams.
The first video is dated 11th March 2011 (going by the clock in the bottom right of the video). It starts at 00:00 Midnight and finishes at 04:00.
The second video is dated 4th April 2011 and it's starts at 04:00 and finishes at 08:00.
The reason I'm showing these videos is because there are UFOs (lights) hovering in the sky above the volcano that can be seen in both of the top pictures.
The top left picture also has what looks like UFOs flying backwards and forwards in a straight line at the bottom of the volcano. These lights stop at about 05:30 in the second video.
I've watched these videos quite a few time now and I've come to the conclusion that there is a road there at the foot of the volcano. What you can see is the headlights of the cars driving by. They are flashing unevenly because the road is behind a row of trees. The lights stop at about 05:30 on the second video. That must be the time when the sun comes up and the drivers turn off the headlight. The lights look like they are too fast to be cars going by until you realise that the video is playing at high speed. Watch the clocks at the bottom right side of each video and you'll see that the minutes are going by at about 1 per second.