At first I was misreading the markings on this bowl as GHP and couldn't read if it was Ireland or Iceland ..but as there was nothing Irish looking about it at all, I did a search for "Lava Bowl GHP Iceland" and bingo! up came the maker.
I was misreading the GHP, which turns out to GLIT. It is a piece made by Glit Iceland which was founded by Ragnar Kjartansson in 1958. A pottery which seems to have specialised in using Icelandic volcanic lava (pumice, rock, ash) in glazes on their pottery.
I found a short entry on Kjartannson on Wikipedia:
Ragnar Kjartansson (1923 - 1989) was an Icelandic sculptor. He was a member of the Icelandic Sculptors Society which he established in the Icelandic capital in 1972 along with Hallsteinn Sigurðsson, Jon Gunnar Árnason Þorbjörg Pálsdóttir and others. He was also the founder of Glit, Ltd., the only ceramic factory in the country. One of his works is located along the main road in Eskifjördur, commemorating the mariners who drowned at sea.
A search online will yield many very attractive looking pieces from this Icelandic Pottery.
The red in the centre of this largish bowl contrasts beautifully with the green outside, and really goes to make it look like a piece of molten lava cooling down.