Rabaul Caldera


Rabaul caldera is a large volcanic structure on the northeastern end of New Britain Island in Papua New Guinea.  The volcano is famous for the well developed ring-fault and the 1994 eruptions that destroyed the town of Rabaul.

It is clear from the history of eruptions that there is an interconnected plumbing system within the caldera.  Eruptions in 1934 and 1994 had simultaneous activity at Vulcan and Tavurvur cones which are on opposite sides of the caldera, separated by about 6 km.

Exposed seafloor on Vulcan headlands caused by  ~6 meter uplift prior to eruption.
Note the tidegauge post on the right which is far out of the water.

   Composite photo taken by RVO staff of beginning of eruption on September 18m 1994.  Tavurvur on the east side of the
caldera (left)began erupting at 6:06 am and this picture shows the begining of the Vulcan eruption on the west side of the
caldera (right) at about 7:20 am.

One important research issue is to understand the configuration of the magma conduits within the volcano.  The vents at Vulcan on the west and Tavurvur on the east must be connected, either through narrow pathways or a large central magma reservoir.  Tomographic results show a rather small low-velocity zone at shallow depths in the central part of the caldera which is probably a source of magma, but it is still uncertain if there is a large reservoir at greater depth underlying the caldera.


Ash erupttions from Tavurvur on November 6, 2000.


Earthquakes assoicated with explosions on November 6, 2000.



Rabaul Volcano Observatory                     Director, Ima Itikarai