Rabaul Eruption, Papua New Guinea, 1994

Volcano on New Britain Island Caused Mass Evacuation and Destruction

Aug 25, 2009

An eruption of two vents in the Rabaul caldera, Vulcan and Tavurvur, forced the evacuation of residents, buried the airport and collapsed most buildings in the city.

Rabaul is a caldera which is an active volcano situated on the Gazelle Peninsula at the northern tip of New Britain Island in Papua New Guinea. On the eastern rim of the caldera, an opening formed approximately 1,400 years ago and it allowed water to enter. This is now known as Blanche Bay.

On the northern and northeast sections of the Rabual caldera rim, there are three stratovolcanoes. There have been several eruptions on the caldera floor near the western and northeast walls. These have produced several cones, including Vulcan and Tavurvur that are still active to this day. It was these two cones that erupted on September 19, 1994.

Events of the 1944 Rabual Eruption

The first signs of a pending eruption began on Sunday, September 18th, 1944 and this was preceded with less than a day of seismic activity. Usually, small earthquakes will occur months or weeks before an eruption.

Despite short notice of the eruption of Rabual, the New Guinea Emergency Services acted quickly and had an emergency plan in place. Over 30,000 people were evacuated from Rabaul to the neighboring towns of Kocopo and Kerevat before the eruption took place.

Tavurvur, located on the east side of the caldera, was the first vent to erupt and it occurred in the early morning on September 19, 1994. Soon the Rabalanakaia vent on the northeast side began to erupt. Both of these eruptions were not intense.

Within a few hours, the Vulcan vent on the west side of the caldera experienced a violent eruption and sent an ash plume over 60,000 feet into the air. This eruption deposited a thick layer of ash over the area.

On September 19th, several vents below the surface of the water in the caldera began to erupt. After this day of multiple eruptions, volcanic activity continued only at the Vulcan and Tavurvur vents.

By September 21st, the volcanic activity quieted down and the ash plume was reduced to 20,000 feet. The following day, there were violent eruptions from Vulcan and Tavurvur. The eruption of Vulcan sent pyroclastic flows down the side of the caldera and to a distance of three miles.

People who had evacuated to Kerevat had to be sent farther away because the ashfall became very heavy. During the eruptions, air traffic was diverted around the ash column.

Destruction Caused by the 1994 Rabaul Volcano

In the water-filled caldera, known as Blanche Bay, Matupit Island sunk below the sea. The bay was covered with floating pumice and volcanic material filled part of the harbor. The ash clouds produced severe lightning activity and heavy rain, which soaked into the ash fallout on the ground. This made the blanket of ash heavier and caused buildings to collapse. It also triggered flooding and mudflows that closed down transportation and communication.

According to a bulletin issued by the US Geological Survey on September 23, 1994, “The rains soaked the thick ash that has fallen on buildings, the combined weight has collapsed an estimated 80% of the buildings in Rabaul. The ash is estimated to be at least 2.5 feet thick throughout the city with other areas having as much as 5-7 feet of accumulated ash.”

Geoscience Australia reported, “By September 23, five people had been killed, four from roof collapse and one from lightning, and 53,000 people had been displaced.” The US Geological Survey reported that one man was run over by a truck during the evacuation of Rabaul. The airport at Rabaul was buried by volcanic debris and was never reopened. It was rebuilt at Tokua. The city of Rabaul has been slowly rebuilding but Kokopo became the new capital city after the 1994 eruption.

The Rabaul Volcano Observatory, established after a major eruption of Vulcan and Tavurvur in 1937 where over 500 people were killed, continues to monitor the caldera at Rabaul and on nearby islands.