Aotearoa Summary. 9 December 2019 - 17 December 2019
Low level ash or phreatic eruption possible at White Island. White Island has remained hot since the end of the previous forecast period. Spaceweather conditions are very mild and not likely to last more than one day. Quakes are likely to be isolated. Forecast confidence = low. The 11.52pm 8 December Cape Campbell 4.3 occurred as this forecast was being processed. Update. 11 December 12.00am 9 December. White Island 2.11pm 10 December. South of Gisborne 5.3 12.58pm Mild spaceweather arrived on cue. The moderate phreatic (steam) and ash eruption of White Island has made world headlines. Many tourists visiting the volcano were burnt by the hot ash and steam blast. A dramatic rescue has taken place with fatalities and some bodies left behind on the island. Quake risk locations and magnitudes were reduced as the forecast focussed on White Island. Spaceweather picked up unexpectedly on 10 December and a significant South of Gisborne 5.3 followed. Solar conditions are mild but steady tonight and may have enough energy to drive a late quake before fading away. The forecast period is extended to 11 December. Hawkes Bay, Cape Campbell, Lower Awatere, Ward, Kaikoura, Hanmer, Murchison, St Arnaud are added to Mag 4 risk locations. Possibility Mag 5 New Zealand. Mag 5 confidence=low. Volcanos quiet. Update. 11 December 10.00am 11 December. Kaikoura 4.0 3.48am The addition of Kaikoura to Mag 4 risk locations is justified. Spaceweather is mild and steady overnight. Methven is added to Mag 4 risk locations. White Island seems to be slowly heating again. Phreatic (steam) activity and strong degassing seems likely at White Island today. Update. 11 December 7.45pm Tremor has increased dramatically at White Island today. Possibility for significantly larger eruption at White Island than 9 December. The forecast period is extended to 12 December. Update. 13 December 11.00am Local quakes are under Mag 4. White Island is very hot but no eruption. Spaceweather faded on 12 December. New solar conditions are due this afternoon, increasing to a mild peak on 14 December. Isolated Mag 4/5 quakes are possible. Mag 5 confidence=low. White Island has extremely high tremor at all frequencies and another bigger eruption seems likely. A recovery team is at the volcano today. Hopefully they can get the job done quickly. A stronger quake and eruption peak is due 18 December. Update. 14 December 8.30am The forecast period has probably ended. Tremor at White Island is consistent with an eruption last night at 10pm approximately. Quakes are quiet and likely to stay that way until a new forecast period begins 18 December. Hopefully vulcanologists will confirm the eruption today. Soldiers recovered six bodies from the crater yesterday. Two people remain missing. Summary. 9 December. White Island 2.11pm 10 December. South of Gisborne 5.3 12.58pm 11 December. Kaikoura 4.0 3.48am 13 December. White Island 10.00pm approx. 14 December. Southern Kawekas/Ngmatea 4.9 9.21am 15 December. 10km Northeast White Island 5.0 10.52pm 17 December. 50km Northwest White Island 4.2 2.32pm The forecast period has become world news as a small eruption at White Island left 47 tourists and guides dead or fighting for their lives. East Coast risk locations were reduced as the forecasters focussed on White Island. The South of Gisborne 5.3 soon followed in often forecasted Wairoa/Mahia (Murphys Law). Tremor kept rising at White Island following the first eruption and a second eruption late 13 December was followed by a period of quiet. Details from vulcanologists are sketchy for the second nightime eruption. They announced a brief period of ash emissions was followed by quiet. The first eruption was similar and many recording instruments were not functioning during the second eruption, limiting observations. The addition of Kaikoura to Mag 4 risk locations was justified on 11 December. Following three days with no quakes the period looked to have ended but a late quake in the Southern Kawekas wasn't in a risk location despite nearby Hawkes Bay. The 15 December deep White Island 5.0 was in similar position to the 24 November White Island 5.9. Vulcanologists announcement that the 24 November White Island 5.9 was unrelated to volcanic activity was clearly a mistake. Deep quakes under volcanos are eruption precursors. Aotearoa Earthquake and Volcano Forecast Service © 2013 - 2024 |
