11.25" x 2.75"
The biggest submarine volcanic eruption known is Havre volcano. The deepest part of the world's oceans in the western Pacific is known as Mariana Trench -- it's about 1,580 miles long with an average width of 43 miles. It reaches a maximum-known depth of 36,070 feet at a small slot-shaped valley in its floor known as the Challenger Deep. The brown band surrounding the center on this bowl is from the Challenger Deep.
On porcelain from center outward, Havre pumice/mud, Mariana Trench, crushed blue seaglass, written provenance, Mid-Atlantic Ridge rock slurry, and more Havre volcano-mud.