Unknown lights. boat capsized area in Hokkaido Japan

Dear everyone,

I found strange triple lights on a sea, where a Japanese sightseen boat capsized in Hokkaido 22nd April. 14 passangers were found dead and 12 are still missing.

Sentinel2 captured the images 24th April, and two more days after this, the boat was found 110m under the sea, where exactly same location of unknown lights.
You can see the small lights, red green and blue, from down link below.

lt looks like just a synthetic error, but I presume these lights could be caused by an underwater prism effects. There’s no sonor ship arrived when this images captured, nor patrolling aircraft.

It would be most greatful if you can assess the identity of lights.
I truly appreciate your time.

Sorry about my poor English, I hope you can understand what I’m trying to say.

Koji@ Tokyo

Hi Koji,

Firstly, I am sorry to hear about the boat accident.
I am new to EO and the Hub, therefore, I still have a lot to learn.
Certainly I can’t tell if it is a bug or data process issue, but I can provide an assumption.
If the location is exactly where the boat is, would it be something coming from the boat itself? (By comparing the size of nearby small boats, the area of the three-lights can potentially be contained in a large tourist boat) Perhaps it reflected a distress signal(as light/smoke)?

P.S. Your English is perfectly clear : )

Best wishes,

1 Like

Hello Hsin-wen, and all users

Thanks indeed for your reply!
I’ve asked to Nikon Co, for investigating about this RGB light.

They said light can’t pass from 110m depth water, except for Red light.
It looks like three lights (RGB) source strength are same brightness, therefore this might be some reflection from sea above level. Besides, they said a satellite picture is taken through three lights, Red Green Blue, and combined one true color picture. At that time, shooting time difference causes slight discrepancy, if it flies at high speed.

They presumed this is probably a surveillance aircraft for patrolling the area, which speed is around 250km. Sentinel2 has just coincidently taken this image when the aircraft flies over the exactly same location of the ship sunken. We can see a same light around Tokyo Haneda Airport.

By the way, salvaging the ship mission is about to start from today.
I wish missing passengers can be found soon.

Thank you very much for your time,
Kind regards,


Hello Hsin-wen and Koji,

We are truly sorry for the tragedy.

@mikuniya your answer seem to be a perfect explanation, indeed this is an effect, observed with fast moving objects. It is therefore certain that it is not a synthetic error .

We wish you all well, with the recovery and salvage mission.


Hi Koji and Dorothy,
@mikuniya thank you for the explanation on the RGB phenomena associated with the high-speed moving objects. I appreciate very much you sharing the investigation outcome from Nikon with us, and providing a further example of the RGB near Haneda Airport.
@dorothyrono thanks for your confirming note on the explanation!
My thoughts go to the victim and their family.
Best wishes,