Aotearoa Summary. 16 March 2020 - 29 March 2020

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Magnitude 5 risk locations are East Cape, Tokomaru Bay, Tolaga Bay, Waipukurau, Dannevirke, Eketahuna.
Magnitude 4 risk locations are Wairoa, Mahia, Northern Hawkes Bay, Opotiki, Whakatane, Rotorua, Urewera, Atiamuri, Taupo, Taumarunui, North of Kapiti, South of Taranaki, North of D'Urville Island, Cape Campbell, Murchison, Mt Cook, George Sound, Te Anau, Doubtful Sound.
Heating at Ruapehu has continued for several days and is slowing but may start heating up again with the arrival of new spaceweather.
No lake temperature data from Geonet but if the crater lake gets above 40C during the period they may make an announcement.
Ruapehu may be added as an eruption risk later in the period.
March is aurora season when even moderate solar wind can cause auroras, due to Earth crossing the Solar Ecliptic Plane.
Earthquakes and eruptions are also more frequent during March and April.
The forecast is likely to be extended for several days.

Update. 17 March 12.00am
16 March.
30km Northwest of Cape Campbell 3.7 1.07am
20km EastSoutheast of White Island 5.0 3.22am
10km North of Culverden 5.1 4.28am
South of Kermadecs 5.0 4.44am
South of Kermadecs 5.0 5.28am
15km South of Hawera 4.1 11.57am
Spaceweather has arrived on cue and so has March earthquake "season".
Heavy quake action across New Zealand today with the heavy push.
Reasonable location success except Culverden, the large number of North Island risk locations justified by the heavy action.
Spaceweather is set to continue for several more days.
Quake periods often start with a burst of quakes, followed by several days of quieter action then another burst as the period ends.
Quakes may ease 17 March as a buildup begins towards a second peak 21 March and the end of the period.
Possibility Mag 6. North Island higher risk.
South Wairarapa is added to Mag 4 risk locations.
More Mag 4 quakes are possible at Culverden, Waiau, Hundalees.
Volcanos are fluctuating and difficult to forecast.
White Island and Ruapehu cooled yesterday but are moderately heating again today.
Heating seems likely to continue at Ruapehu next few days with a possible eruption very late in the period.

Update. 17 March 11.00pm
17 March.
Lake Te Anau 3.8 1.08am
Quakes have eased 17 March as expected but forecast conditions are tricky.
Tremor is very high on the Volcanic Plateau and Bay of Plenty.
White Island and Ruapehu are also heating again.
Conditions seem more likely for quakes rather than eruptions although confidence is low.
The mechanism for switching between quakes and eruptions is poorly understood.
Spaceweather has increased again today and likely to continue at moderate level for a couple more days at least.
Mag 6 is possible 18 March on Volcanic Plateau, Bay of Plenty, East Cape. Confidence=low.
White Island is probably steam pluming.
Ruapehu could still become active very late in the period.
Vulcanologists are likely to make an announcement if the crater lake gets above 40C and close to eruption temperature.

Update. 18 March 10.30pm
18 March.
South of Catlins 4.7 1.19am
Local quakes are widespread during the period with a moderate quake in very unusual location Offshore Catlins.
Vulcanologists have announced today that Ruapehu crater lake is now 40C but that heating has slowed.
The lake probably needs to get to about 45C before erupting.
Mild spaceweather today isn't driving heating at the lake but new spaceweather due 19 March may cause a resumption of the heating and possible eruption or strong degassing from 20 March.
White Island is also likely to heat up from 20 March and strong steam pluming seems possible.
Indicators for strong quake action on the Volcanic Plateau, Bay of Plenty, East Cape may be mistaken for volcanic tremor...time will tell.

Update. 19 March 10.30pm
19 March.
10 Km SE of Dannevirke 3.9 4.24am
Northeast of East Cape 5.1 5.56am
Masterton 3.7 4.13pm
Spaceweather has picked up again today, quakes have followed.
Wairarapa has become active, justifying additional South Wairarapa risk location.
More Mag 5 action at East Cape is making the period into a strong one.
Tremor at Ruapehu has increased slightly.
Degassing seems possible if the crater lake is heating towards 45C.
No temperature data or announcements from the vulcanologists today.
The period is unusual with both quakes and volcanic heating when usually it is only one.
The period is extended to 20 March.
Mag 6 remains possible in North Island. Confidence = low.

Update. 22 March 12.00am
20 March.
South of Kermdecs 5.4 2.36pm
Heavy action north of New Zealand continues.
Local quakes are at low magnitude but very busy especially in Northern Wairarapa.
Tremor at Ruapehu and White Island continue.
This is the first time quakes and volcanic tremor are observed together at such a high level...usually it is just quakes or just volcanic tremor.
Spaceweather has increased on 21 March and is likely to continue for another two or three days.
Isolated quakes at high Magnitude are possible 22 March.
Possibility Mag 6 New Zealand. Confidence=low.
Northern Wairarapa, Southern Hawkes Bay is higher risk.
White Island is likely to have a continuous steam plume.
Possibility strong degassing or minor eruption Ruapehu.
Ruapehu crater lake was 40C three days ago and steady but may resume heating up to the eruption temperature 45-46C with the increase in spaceweather.

Update. 23 March 11.00pm
Local quakes are below Mag 4.
Spaceweather has eased last two days but remains above the quake driving threshold.
Very difficult to forecast fluctuating spaceweather is likely to continue 24 March, picking up on 25 March.
Quakes are likely to remain isolated on 24 March but high magnitude is still possible from such an active long lasting period.
Risk locations and magnitudes haven't changed so the forecast map is retained.
Tremor at Ruapehu is steady.
No announcements from the vulcanologists so the lake temperature may have steadied?
Volcanic eruptions tend to follow quakes and come very late in the period so an increase in spaceweather on 25 March could drive the crater lake temperature higher.

Update. 27 March 4.00pm
25 March.
Ward 4.4 (4.8 USGS, EMSC)
26 March.
Feilding 3.9 2.48am
Porangahau 3.5 3.10am
Persistent mild spaceweather continues on 27 March, marking a long forecast period.
Quakes have followed the spaceweather.
The Ward 4.4 seems very widely felt for such a small quake so the forecasters prefer USGS 4.8.
Additionally, USGS usually record local quakes about Mag 0.2 lower than Geonet but this time they are Mag 0.4 higher, meaning Geonet should be about Mag 4.8-5.0....you decide.
More quakes near or in higher risk Northern Wairarapa show that quakes are migrating into the lower North Island, Cook Strait from North of East Cape early in the forecast period.
Volcanic Plateau is going quiet as action moves into Wairarapa.
Tremor at Ruapehu is easing back and the crater lake temperature stable or cooling.
No announcements from the vulcanologists for nine days since the crater lake reached 40C.
An eruption at Ruapehu now seems unlikely.
Persistent mild spaceweather is likely to remain until a slight peak on 31 March.
Isolated local quakes are possible 27/28 March.
Wairarapa, Eastern Taranaki Bight, Cook Strait are higher risk locations.
Mag 6 risk is declining and low confidence.

Summary.
16 March.
30km Northwest of Cape Campbell 3.7 1.07am
20km EastSoutheast of White Island 5.0 3.22am
10km North of Culverden 5.1 4.28am
South of Kermadecs 5.0 4.44am
South of Kermadecs 5.0 5.28am
15km South of Hawera 4.1 11.57am
17 March.
Lake Te Anau 3.8 1.08am
18 March.
South of Catlins 4.7 1.19am
19 March.
10 Km SE of Dannevirke 3.9 4.24am
Northeast of East Cape 5.1 5.56am
Masterton 3.7 4.13pm
20 March.
South of Kermdecs 5.4 2.36pm
25 March.
Ward 4.4 (4.8 USGS, EMSC)
26 March.
Feilding 3.9 2.48am
Porangahau 3.5 3.10am
27 March.
Offshore Doubtful Sound 4.6 6.56pm
29 March.
10km North Cape Campbell 4.8 1.18am
Southeast of Dannevirke 3.7 2.37pm
A long and very active forecast period has evolved with persistent steady spaceweather driving the action.
The period still has at least two days and possibly longer to run so more quakes are likely.
Risk locations have changed for the next days so a new forecast map will be posted for the remainder of the period.
Quake action during the period has moved steadily south into Wairarapa, Cook Strait.
Fiordland has also seen significant action.
Canterbury is also receiving minor quake action in addition to the Culverden 5.0 which began the period.
Unusually, volcanic heating is underway in addition to quakes...usually it is one or other.
White Island and Ruapehu have been hot through the period.
Heating at Ruapehu reached 40C on 18 March but the vulcanologists have been silent since then.
Tremor at Ruapehu indicates the crater lake temperature is stable.
Vulcanologists will make an announcement if the lake gets to 43C.
Spaceweather has been strong enough during the period to cause a significant jetstream shift and an outbreak of polar storms.
A cold snap in New Zealand has left snow on the mountains and broken an intense summer drought in the North Island and Upper South Island..

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