During 22-28 March, eruptions continued at Rabaul caldera's active Tavurvur cone every 10-20 minutes. These intervals were longer than during the previous weeks. Ash clouds rose several hundred meters above the summit. Moderate ash fell in Rabaul Town during 25-28 March. There were 100-200 earthquakes daily associated with the eruption. No changes were recorded in ground deformation. People were discouraged from entering within 1 km of the erupting vent.

Source: Rabaul Volcano Observatory (RVO)

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.