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| Subduction Retrieval |
 Title text: Aww, the oceanic crust and the continental crust are getting married! |
Explanation
This comic is a public service announcement (PSA) telling the reader to stay out of the Pacific Ocean on the current day. The reason for this is explained to be that someone has lost their wedding ring in a subduction zone. This is a boundary where two tectonic plates in the Earth's crust collide, and one plate dives beneath the other into the Earth's mantle. The ring can be seen glimmering on the upper surface of the subducted oceanic plate, in the accretionary wedge below the continental plate. Given that the rate at which this occurs is of a few centimetres per year at most, and assuming that the characters shown are drawn to scale and are of average human stature, it can be estimated that the ring has been in the subduction zone for about 200 years. Possibly this time has been needed to localise it and then deploy the heavy engineering displayed.
As a result, the United States Geological Survey (USGS) is "pulling the plate back up" to retrieve the ring. This would be a ridiculous idea, since no man-made machine is capable of moving entire tectonic plates[citation needed]. Even if it were possible, it is unlikely that the USGS, a national organisation, would invest the time and effort required for such an operation for the relatively trivial purpose of retrieving a wedding ring, particularly for people who are presumably long since dead.
The title text jokes that since the wedding ring lies on the lower (oceanic) plate, the oceanic crust and continental crust are "getting married".
Transcript
[A large crane machine, with one foot in the sea, & another on the neighboring plate, is using a winch to pull up a tectonic plate from the mantle, containing a wedding ring latched on to it. Two people stand on the pulled-up plate, presumably surveying the lift, & a third person stands on a neighboring (unaffected) plate, watching the scene. The second plate itself has various hills & crannies on it.]
Crane:click click click.
[Caption below panel:] PSA: Please stay out of the Pacific Ocean today. Someone lost their wedding ring in a subduction zone and USGS is pulling the plate back up to retrieve it.
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