Seismicity was very high during 4-6 March and then declined in the evening of 7 March. Three regional earthquakes felt during this period ranged in magnitude from 5.1-5.5, and occurred SSE from Rabaul offshore outside the Wide Bay area at depths ranging between 50 and 60 km. They were felt in Rabaul town with intensities of III-IV. Emissions were absent during 8-11 March.
Activity resumed on 12 March at 1108. An explosion ejected tephra and a gray-to-black billowing ash plume rose 300 m and drifted SE. The forcefulness and color lessened over at least the next 40 minutes; ash plumes rose 100 m, but were carried to 1 km with the wind. Seismicity remained low. [less]

from the latest Smithsonian / USGS Weekly Volcanic Activity Report: [less]

The following is the Smithsonian / USGS activity summary for the past days:
"RVO reported that roaring and rumbling noises from Rabaul caldera's Tavurvur cone began at 2128 on 19 January and lasted for about 15 minutes. Darkness prevented visual observations but the next day ash emissions were evident. [less]

The eruption was preceded by several days of increased SO2 emissions that was smelt in the area and affected plants. This ends the period of slumber, Tavurvur had been in since since August 2011.
The following youtube video shows the eruption on 22 Jan generating an ash plume rising a few hundreds of meters above the cone: [less]