New Zealand's green White Island Volcano

In summary, the green ash at White Island was due to a combination of unique minerals and the sulphur content.
  • #1


Staff Emeritus
Science Advisor
New Zealand

White Island, off the northern coast of New Zealand in the Bay of Plenty, had a small explosive eruption on the evening of April 27. This was the first eruption at White Island since October 2013 and the explosion carved a new crater inside the larger crater area of Ruapehu. The eruption was preceded by an earthquake swarm, but luckily the biggest consequence of the eruption was greenish ash covering the crater floor and some of the GNS Science monitoring equipment.

I've not heard of green ash before. Is it mineral or perhaps algae/plant matter?

Ruapehu had a brief earthquake swarm last week under the volcano. The crater lake at the volcano’s summit also experienced warming. The swarm was a little out of the ordinary for Ruapehu, but the unrest seems to have quickly subsided and the temperature of the crater lake has also declined. According to the new article, the lake has warmed over 15ºC over the last few weeks, peaking at 42ºC.
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  • #2
Astronuc said:
I've not heard of green ash before. Is it mineral or perhaps algae/plant matter?

haven't heard of the green ash either.
I know the hot pools within the crater are quite colourful with various algae, but I wouldn't have thought it would have been enough to produce
such a noticeable colour change in the surface of the crater walls if this water was then ejected out of the crater

I might send GNS an email and see if they have an explanation :smile:

  • #3
OK email sent ...

Hi guys

In reference to the latest White Island activity on the 27 Apr 2016 and this photo and article ...

Several of us are wondering where the distinct green colouring in the ash is coming from ?
Have seen a lot of different coloured volcanic ash over the years, but green hasn’t been one of them
We are wondering if the ash is naturally that colour ... what chemicals present would cause that ??
Or if maybe it is tainted by the algae in the crater hot pools ?

  • #5
well it took a while, but a response was forthcoming :smile:

Morning Dave,

Sorry for the slow reply.

The eruption deposit was green due to a combination of unique minerals. The ash contained pale yellow sulphur which played a big part of the colouring.

You can read a bit more here:

Kind regards,

some more discussion within that link

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What is the history of White Island Volcano?

White Island Volcano is an active volcano located off the coast of New Zealand's North Island. It has been continuously erupting for at least 150,000 years and has had several major eruptions in the past century.

How often does White Island Volcano erupt?

White Island Volcano is known for its frequent eruptions, with the last major eruption occurring in 2019. It has a history of erupting every few years, but the frequency and intensity of eruptions can vary greatly.

What makes White Island Volcano unique from other volcanoes?

White Island Volcano is one of the most active and accessible volcanoes in the world. It is also the only active marine volcano in New Zealand and is located on a privately owned island, making it a popular tourist destination.

Is White Island Volcano dangerous for tourists?

While White Island Volcano is constantly monitored for potential hazards, it is still an active volcano and can be dangerous for tourists. Visitors are required to wear protective gear and follow strict safety protocols when visiting the island.

What research is being done on White Island Volcano?

Scientists are constantly studying White Island Volcano to better understand its behavior and potential hazards. This includes monitoring gas emissions, seismic activity, and conducting geological surveys to track changes in the volcano over time.

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