TheRabaul caldera, orRabaul Volcano, is a largevolcano on the tip of theGazelle Peninsula inEast New Britain,Papua New Guinea, and derives its name from the town ofRabaul inside thecaldera. The caldera has many sub-vents,Tavurvur being the most well known for its devastating eruptions overRabaul. The outer flanks of the highest peak, a 688-metre-high asymmetricalpyroclastic shield, are formed by thickpyroclastic flow deposits.[1] There is no sign of a pyroclastic shield along the rim of the caldera, making the location likely underwater, on the caldera's floor.
Tavurvur, astratovolcano and a sub-vent of the caldera, is the most visibly active, continuously throwing ash. In 1994 it, and nearbyVulcan, erupted and devastated Rabaul; however, due to planning for such a catastrophe, the townsfolk were prepared and only five people were killed. One of the deaths was caused by lightning, a feature of volcanic ash clouds.[2][3][4]
In 1937, Vulcan and Tavurvur erupted simultaneously, killing 507 people. This event led to the founding of theRabaul Volcano Observatory, which watches over the many active volcanoes in Papua New Guinea.[5]One eruption over several days in March 2008 released a plume of ash and water vapor that drifted northwest over theBismarck Sea.[6]
535 AD: There is evidence of a large eruption at Rabaul, that may be the event recorded in chronicles of the reign of Byzantine EmperorJustinian I as ruining the climate and helping to bring on theMiddle Ages. But it is not certain, as there are other possible culprits, includingIlopango inEl Salvador inCentral America.
683 AD ± 2 years: There was aVEI force 6 eruption at Rabaul, dated by correctedradiocarbon;[7] there is an opinion[8] that that eruption formed the Rabaul Caldera sea-inlet.
1950s: A government vulcanological observatory was established on the northern ridge of Rabaul caldera.
19 September1994: Tavurvur and Vulcan erupted, destroying Rabaul airport and covering most of Rabaul town with heavy ashfall. Vulcan has remained quiet since. For more information seeRabaul#1994 eruption.
7 October2006: Tavurvur erupted again, and an initial blast broke windows up to 12 kilometers away and sent an ash plume 18 km into the stratosphere.[10] Winds blew most of the ash away from Rabaul.
23 July 2010: Eruptions at Tavurvur volcano resumed after nearly seven months without ash emissions.
2–8 April 2010:Seismicity was low and variable amounts of white vapor rose from Tavurvur cone.
9 April 2010: The Rabaul Volcano Observatory (RVO) reported thatdeformation measurements at Rabaul caldera during the previous 3–4 months had shown an inflationary trend with a total of 4 cm of uplift.
22 July 2010: RVO detected increased seismicity (likely beneath Tavurvur cone), as a few small hybrid earthquakes, followed by small low-frequency earthquakes, then continuous volcanic tremor starting at time 1034.
23 July 2010: Tavurvur cone erupted, starting at time 1300. The eruption began with discharge of diffuse white plumes, followed by pink-gray fumes with low ash content. A strong odor ofhydrogen sulfide was noted, and a diffuse cloud rose 1 km and drifted NW. A few hours later, observers saw billowing gray clouds, accompanied by roaring and rumbling noises. Ashfall was reported in areas to the cone's NW and NNW.
23–26 July 2010: RVO reported that seismicity was variable. Ash emissions and ashfall continued in areas to the northwest. Visibility remained poor in Rabaul town (3–5 km NW of Tavurvur) due to ash made airborne by moving vehicles. Ash emissions ceased on 25 July. Later that day and into 26 July only diffuse brown-tinted vapor plumes were emitted and seismicity was very low.
After this eruption, GPS data showed deflation of Tavurvur cone. Seismicity was very low, and diffuse white plumes were emitted during 26–30 July.[11]
29 August 2014: Tavurvur started a VEI 3 eruption,[12] around 3:30–4:00 AM local time (28 August 2014, 17:30–18:00 UTC) prompting concerns over disruption of flights in Australian airspace due to the large ash clouds (up to 15 km (50,000 ft).[13] Communities near the volcano were evacuated, while residents of the town ofRabaul were advised to remain indoors to avoid falling ash, according to a statement from Australia's Department of Foreign Affairs and Trade.[14] TheVEI of this eruption was 3–4.
