Likely activity on Mount Michael

In the satellite images from the 11th and the 12th December 2014 on the EOSDIS website, I noticed what looked like a possible eruption which took place. In the image from 11th December, it looks what appears to be a dubious looking plume originating from the summit area of Mount Michael on Saunders Island drifting in a southwesterly direction. In that image it wasn't easy to confirm whether that was an eruption plume or not. In the image from 12th December, a dark strip appears on the southwest flank of Mount Michael giving a strong indication that an eruption had took place. In my personal opinion, it looks volcanic so it could either be ash deposits, or a lava flow, or both.

What appears to be most likely a plume originating from Mount Michael and drifting southwest in this image from 11th December 2014. SOURCE: NASA.

A dark strip on the southwest flank of Mount Michael is a strong indication that a recent eruption took place in this image from 12th December 2014. SOURCE: NASA.

Possible gas plume on Mount Michael

LANDSAT 8 satellite imagery from 6th December 2014 shows what appears to be a gas or water vapour plume originating from the summit area of Mount Michael on Saunders Island. Because the west flank is covered in mist it is not easy to tell for sure whether it really is an emission or if it is just a wind current. Thermal imagery could not pick up any thermal anomalies from the same area so I am under the opinion that it is either water vapour related, or that it could be weather related.

Water vapour? wind current? SOURCE: Landsat 8/USGS/NASA.

Thermal hotspots on two islands

Satellite imagery from the 24th September 2014 showed a thermal anomaly on Saunders Island and Zavodovski Island.

In the image of Saunders Island, thermal anomalies are present inside the summit craters of Mount Michael but nothing unusual shows up in the natural colour image suggesting that it may be no more than elevated ground temperatures inside the craters with slight fumarolic activity at best.

Nothing unusual also shows up in the natural colour image of Zavodovski Island but however, a strong thermal anomaly was present around the crater area of Mount Curry which suggests that it's more likely to be intensive fumarolic activity although I personally wouldn't rule out a small possibility of it being pyroclastic deposits.

Heat sources in the craters of Mount Michael. SOURCE: Landsat 8/USGS/NASA.

Strong heat source present on the west side of Mount Curry. SOURCE: Landsat 8/USGS/NASA.

Degassing on Mount Michael

The LANDSAT 8 satellite image of Mount Michael on the 17th September 2014 shows some degassing coming from the summit crater.

Degassing from the summit crater of Mount Michael. SOURCE: Landsat 8/USGS/NASA.

Possible plume?

Between the 27th and 30th August, I noticed what appeared to be a possible plume originating from the Mount Michael volcano on Saunders Island while looking at the EOSDIS website. Because the view was mostly obscured by clouds, it was difficult to determine or verify whether or not it was clearly a plume nor what was going on. If it's a plume then it wasn't easy to tell whether it was an eruption or just a gas plume either. Or it could've simply been a wind current.

What appears to be a plume on the 27th August 2014. SOURCE: NASA.

What appears to be a plume on the 29th August 2014 drifting northeast. SOURCE: NASA.

Weak thermal hotspots on two islands

The thermal imagery of 16th August 2014 shows some weak heat sources on Montagu and Bristol islands. On Montagu Island, a weak heat source is present on Mount Belinda Volcano. But on Bristol Island, 2 weak heat sources are present on Mount Sourabaya and a crater-like structure between Mount Sourabaya and Mount Wales at the centre of the island. The image in normal colour did not reveal anything unusual, but thermal imagery from 12th May 2014 showed the heat sources in exactly the same spots except that they were weaker. So this indicates that the temperature of the heat sources had recently slightly elevated but overall, the heat sources indicate either steady fumarolic activity or elevated ground temperatures in the craters.

Meanwhile on Saunders Island, degassing activity is present on Mount Michael as of 16th August 2014.

Slight heat source on Mount Belinda. SOURCE: Landsat 8/USGS/NASA.

Slight heat sources present on Bristol Island. SOURCE: Landsat 8/USGS/NASA.

Steam plume present on Mount Michael. SOURCE: Landsat 8/USGS/NASA.

August news

On 1st August 2014, I noticed a grey area to the west of Saunders Island on the EOSDIS Worldview website taken by Terra/MODIS. There's a possibilty that it could've been an ash plume from a short lived eruption which drifted away in the winds, or it could just simply be a colouration in contrast with the sea and ice which is hard to identify given the low quality satellite image.

Images from the 7th August 2014 on the Earth Explorer website showed a slight degassing from the summit crater of Mount Michael on Saunders Island. Upon checking the thermal image of Saunders Island from the same date, I discovered that the thermal anomalies which were visible inside the two craters of Mount Michael on 22nd July 2014 were no longer visible. In the thermal image of Candlemas Island from the 7th August 2014, a thermal anomaly is present on Lucifer Hill on the northside of the island. This is likely to be nothing more than fumarolic activity.

Was that an ash plume drifting away from the west side of Saunders Island on the 1st August? SOURCE: NASA.

Just a little steam or gas emission from Mount Michael's summit crater. SOURCE: Landsat 8/USGS/NASA.

Thermal anomaly on Candlemas Island. SOURCE: Landsat 8/USGS/NASA.

Possible dark patch

Since 16th July 2014, I noticed a dark patch on the northeast side of Saunders Island on the EOSDIS Worldview website but because it wasn't of clear resolution, all I could do was just take it like a pinch of salt. However, an image from 22nd July has emerged on the Earthexplorer website enabling me to take a closer look. Through the slightly misty cloud cover and in low light I was able to see on the northeast side of Saunders Island what appeared to be a slightly darkened patch. Was this ash deposits from a possible eruption of Mount Michael? or was it simply a patch of snow melt?

In the thermal image (also from the 22nd July), thermal anomalies were also present inside the summit and secondary craters.

I would personally call this case inconclusive.

Image from the 21st July 2014 showed a possible dark patch on the northeast side of Saunders Island. SOURCE: NASA.

In a better resolution image a slightly darkened patch shows up on the northeast side of the island. SOURCE: Landsat 8/USGS/NASA.

Thermal anomalies show up in the two craters of Mount Michael in this thermal image. SOURCE: Landsat 8/USGS/NASA.

6.9 magnitude earthquake in South Sandwich Islands

A strong magnitude 6.9 earthquake has hit the South Sandwich Islands on the 29th June 2014. The epicenter of the quake was reported to be about 154km north-northwest of Visokoi Island.

Earthquake 29th June 2014. SOURCE: USGS

Possible eruption of Mount Michael in April?

During the second half of April while I was browsing satellite images of the South Sandwich Islands in the rare clear skies, I noticed a plume extending from Saunders Island's Mount Michael volcano. The image from 23rd April showed what appeared to be likely a gas plume extending to the northwest, and the image from 24th April showed a little greyish plume originating from the summit area of Mount Michael.

Upon studying the images from those days and other days, I could not find any evidence of a blackened area and plus the images on the EOSDIS Worldview website are not clear enough as there's only so much you can zoom in. When looking at images from the Earthexplorer website (you can download better resolution pics and zoom in), I found what appeared to be a plume with slight ash content on an image from 17th April plus what appeared to be some slight incandescence in the crater area. However, it was partially cloudy in that image so it was overall not easy to determine whether an eruption took place or not.

So I would deem this event inconclusive.

What appears to be a gas plume extending northwest from Saunders Island in the image from 23rd April. SOURCE: NASA.

What appears to be a greyish plume rising from the summit area in the image from 24th April. Was it dense degassing? was it an ash plume? SOURCE: NASA.

Not easy to tell when it's partially cloudy. SOURCE: Landsat 8/USGS/NASA.

Some quick info

I won't go in depth, but here is some quick information about each island in the South Sandwich Islands from north to south. I will also list the most recent eruptions of each volcano in the chain.

ZAVODOVSKI

Highest point: Mount Curry (aka Mount Asphyxia) 551m

LESKOV

Highest point: Rudder Point 190m

VISOKOI

Highest point: Mount Hodson 835m

CANDLEMAS

Highest point: Mount Andromeda 550m

VINDICATION

Highest point: Quadrant Peak 430m

SAUNDERS

Highest point: Mount Michael 990m

MONTAGU

Highest point: Mount Belinda 1370m

BRISTOL

Highest point: Mount Darnley 1100m

BELLINGSHAUSEN

Highest point: Basilisk Peak 255m

COOK

Highest point: Mount Harmer 1115m

THULE

Highest point: Mount Larsen 710m

The most recent eruptions at the time of this writing on each volcano within the island chain (this does not include possible eruptions):

PROTECTOR SHOAL 1962

MOUNT CURRY (AKA MOUNT ASPHYXIA) 1819

LUCIFER HILL 1911

MOUNT MICHAEL 2006

MOUNT BELINDA 2007

TURMOIL POINT-MOUNT SOURABAYA 1956

BASILISK PEAK 1975

Introduction

As the South Sandwich Islands are very rarely covered, I thought I'd create a blog covering the volcanic activity of these South Atlantic islands. Due to the remote location of the South Sandwich Islands and the fact that they're uninhabited, it is often hard to get observations of them so one has to rely on satellite images to determine what events are occurring. But I do not expect to be posting a lot on here.

I will be posting mainly about any satellite observations I may find no matter how small the volcanic activity is, and also about any earthquakes above the magnitude of 6 which may occur. Also will post other material about the South Sandwich Islands and even South Georgia Island if I feel it's worth posting.

As for the earthquakes, I won't bother writing about them should the magnitude be below 6. The reason for this is because the South Sandwich Islands are uninhabited islands so it wouldn't be worth writing about weaker earthquakes. The source of the earthquake data will come from USGS.