The Tanga Islands are an island

Island

An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

 group in Papua New Guinea

Papua New Guinea

Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...

, located northeast of New Ireland

New Ireland (island)

New Ireland is a large island in Papua New Guinea, approximately 7,404 km² in area. It is the largest island of the New Ireland Province, lying northeast of the island of New Britain. Both islands are part of the Bismarck Archipelago, named after Otto von Bismarck, and they are separated by...

 and part of the Bismarck Archipelago

Bismarck Archipelago

The Bismarck Archipelago is a group of islands off the northeastern coast of New Guinea in the western Pacific Ocean and is part of the Islands Region of Papua New Guinea.-History:...

. The islands are the remnants of a stratovolcano

Stratovolcano

A stratovolcano, also known as a composite volcano, is a tall, conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile and periodic, explosive eruptions...

 which collapsed to form a caldera

Caldera

A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...

. Lif (283 m), Tefa (155 m), and Malendok (472 m) islands are on the caldera rim, while Bitlik and Bitbok islands are 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...

s constructed near the center of the caldera.

Former Prime Minister of Papua New Guinea

Prime Minister of Papua New Guinea

The Prime Minister of Papua New Guinea, is Papua New Guinea's head of government, consequent on being the leader of the party or coalition with majority support in the National Parliament. Since 2 August 2011, the Prime Minister has been Peter O’Neill of the People's National Congress Party.-List...

 Julius Chan

Julius Chan

Sir Julius Chan GCL GCMG KBE was Prime Minister of Papua New Guinea from 1980 to 1982 and from 1994 to 1997. He is currently Member of Parliament for New Ireland Province, having won the seat in the 2007 national election...

is a native of the Tanga Islands.