Metis Shoal is a shoal

Shoal

Shoal, shoals or shoaling may mean:* Shoal, a sandbank or reef creating shallow water, especially where it forms a hazard to shipping* Shoal draught , of a boat with shallow draught which can pass over some shoals: see Draft...

 at the top of a submarine volcano

Submarine volcano

Submarine volcanoes are underwater fissures in the Earth's surface from which magma can erupt. They are estimated to account for 75% of annual magma output. The vast majority are located near areas of tectonic plate movement, known as ocean ridges...

, located between the islands of Kao

Kao (island)

Kao is an island and stratovolcano in Tonga. It reaches above sea level, the highest point in Tonga. The date of its last eruption is unknown, and fresh lava flows are not seen, but the absence of deep erosional gullies or high sea cliffs suggests a very recent origin. It lies about north of...

 and Late

Late (Tonga)

Late Island is an uninhabited volcanic island southwest of Vavau in the kingdom of Tonga.The small, 6-km-wide circular island of Late, lying along the Tofua volcanic arc about 55 km WSW of the island of Vavau, contains a 400-m-wide, 150-m-deep summit crater with an ephemeral lake...

 in Tonga

Tonga

Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...

. When the volcano erupted in 1995 a 43 metre high island formed, composed of a solid lava dome

Lava dome

|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...

 above the surface. It was washed away soon after.

On 7 December 2006 the Royal New Zealand Air Force (RNZAF) flew over Metis Shoal and Home Reef

Home Reef

Home Reef is an ephemeral island built by a submarine volcano whose top has repeatedly breached the surface and was subsequently eroded by wave action again...

at the request of volcanologists from the Institute of Geological & Nuclear sciences (IGNS) to take photos of these.