Iceland Hekla Volcano Overprint, Used For What?

Does anyone know what the overprint on the Iceland Hekla Volcano stamp was used for? I've checked the Scott Catalog & looked online, but can't seem to find anything.

Thank you so much! :)
Sue

Issued May 31, 1954

Peter

Most probably it's the usual reason that such low face value single issue surcharges exist: they were running out of low value 5 aur stamps. Rather than reprint the existing old 5 aur stamp (design in use since 1939 and assumes the plate wasn't worn out), the post office then took a higher value that they had plenty of (prevents forgery if someone happens to have quantities of the original stamp) and overprinted it. Note that the 5 aur stamp with the rock (Westmannevium) included in the definitive set of 1950 wasn't issued/wasn't ready for issue until December 13, 1954. Facit catalog has a date of March 31, 1954 for the Hekla surcharge.

I can guess there was probably a rate change around this time that caused a demand for a 5 aur value.

hy-brasil, wow, thank you so much! It makes sense! Thank you thank you!
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