Aotearoa Earthquake and Volcano Forecast Service

Aotearoa Summary. 3 August 2020 - 14 August 2020

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South Island quakes dominated the period.
Several quakes came in or near risk locations.
Rare quake location South of Stewart Island, Fiordland and Macquarie Island far to the south gave critical clues for more Fiordland action.
Fiordland and South of Fiordland were given higher risk on 8 August but not extending the period was a forecasting mistake.
Fiordland quakes arrived 12 August in risk locations.
Sunspot activity is dramatically increasing in August as Solar Cycle 25 arrives in earnest.
A low confidence outlook for a solar flare 23 August approx. remains.
3 August.
Northwest Arm Te Anau 4.1 9.40pm
4 August.
30km North of Motiti Island 4.2 10.50pm
5 August.
Northwest of D'Urville Island 3.8 8.42am
7 August.
15km North of St. Arnaud 3.8 1.57pm
8 August.
20km Southeast of St Arnaud 4.7 7.51pm
9 August.
South of Stewart Island 4.0 6.14am EMSC
12 August.
George Sound 4.0 4.41am
North of Bligh Sound 5.7 10.16pm (4.8 USGS, EMSC)

Update. 9 August 11.45am
8 August.
20km Southeast of St Arnaud 4.7 7.51pm
9 August.
South of Stewart Island 4.0 6.14am EMSC
Extending the forecast period is justified as South Island quakes pick up.
The South of Stewart Island 4.0 this morning follows a Macquarie Island 4.8 two minutes earlier.
Macquarie Island, far to the south of New Zealand, was added to Mag 6 risk locations during the period.
Quakes are infrequent at Macquarie Island so the addition is justified despite being under Mag 6.
Spaceweather is fading today although uncertainty exists for the next day.
The forecast period is extended to 9 August.
Fiordland, South of Fiordland are higher risk.

Update. 8 August 1.00pm
7 August.
15km North of St. Arnaud 3.8 1.57pm
Quakes are infrequent 6-8 August as spaceweather slowly fades.
Biggest local quake, the St Arnaud 3.8 slightly east of target area Matiri.
The brief spaceweather increase forecasted for today is here but weak.
A late quake may occur before conditions fade away.
The forecast period is extended to 8 August.

Update. 5 August 11.15pm
5 August.
Northwest of D'Urville Island 3.8 8.42am
Local quakes were below Mag 4 on 5 August as spaceweather faded.
Biggest quake, the NW of D"Urville Island 3.8 gave some justification for Taranaki Bight risk locations.
Pressure at Volcanic Plateau remains and additionally South of Fiordland today.
Quakes are likely to remain infrequent until 8 August when a minor quake peak may mark the end of the period.
Snares Islands, Puysegur Point are added to Mag 4 risk locations.

Update. 5 August 12.00am
3 August.
Northwest Arm Te Anau 4.1 9.40pm
4 August.
30km North of Motiti Island 4.2 10.50pm
Spaceweather has arrived on cue and quakes have followed.
Perfect location success in Fiordland and a deep indicator quake at Motiti.
Spaceweather is now fluctuating so quakes will slow down in response.
Volcanic Plateau is showing pressure so quakes may follow here during the period.
The forecast period is extended to 5 August.
Quakes are likely to be infrequent.
Olivine Range, Pyke River are added to Mag 4 risk locations.

Forecast.
Magnitude 4 risk locations are Bligh Sound, Northwest Arm Te Anau, Haast, Murchison, Matiri, Lake Grassmere, Cape Campbell, Dannevirke, Waipukurau, Porangahau, Wairoa, Mahia, Tolaga Bay, East Cape, Te Kaha, Whakatane, Kaimai Ranges, Cambridge, Tokoroa, Atiamuri, Taupo, Te Kuiti, Taumarunui, South of Hawera, South of Waverley, North of D"Urville Island.
Volcanos quiet.
The period may last for several days.
Heavy rain forecast for Fiordland and West Coast on Thursday 6 August may become very heavy rain.