After explosions at Tavurvur during June and August 2001, activity decreased through October. During February-March 2002, the Rabaul Volcanological Observatory (RVO) reported that volcanic and seismic activity remained low, with some low-frequency earthquakes recorded. The active vent emitted weak-to-moderate amounts of white vapor. Ground deformation measurements showed no significant changes.

During mid-February, moderate-to-strong gas emissions drifted to the SE and E and damaged vegetation on the adjacent cone South Daughter, suggesting the presence of volcanic gases like sulphur dioxide within the emissions. The last ash-producing activity from Tavurvur occurred in early September 2001. RVO reported that the chance of mild ash activity occurring in the near future is very remote.

A few tectonic earthquakes were felt during mid-February. They were located 35-80 km NW and SW from the Rabaul-Kokopo area. An M 5.6 tectonic earthquake was felt at 0650 on 17 March. The earthquake was located offshore in the Pomio area. On 21 March, some high-frequency earthquakes occurred NE of Rabaul. Since 1995, these high-frequency earthquakes have been associated with eruptive activity at Tavurvur. During mid-March, some earthquakes were felt, unrelated to volcanic activity, that had magnitudes of 5.3-5.6.

Geological Summary. The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor utilized by what was the island's largest city prior to a major eruption in 1994. The outer flanks of the asymmetrical shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the east, where its floor is flooded by Blanche Bay and was formed about 1,400 years ago. An earlier caldera-forming eruption about 7,100 years ago is thought to have originated from Tavui caldera, offshore to the north. Three small stratovolcanoes lie outside the N and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and W caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city.

Information Contacts: Ima Itikarai, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea.