It is more accurate to describe Nisyros as a volcano than as ‘volcanic’.
Lots of bits of countries are ‘volcanic in that they are have areas of either lava (cooled magma) or igneous rock (rock modified by super-heating) … like Edinburgh Castle which sits on a volcanic plug and much of Cornwall which is granite, though there is nothing active going on at the moment apart from the occasional minor croinking of a fault line..
But Nisyros is still huffing and puffing. The organisation GEOWARN is monitoring things on the island partly because it is still active, partly because of the numbers of tourists who flock here each day from Kos for a quick ogle, and partly because access is easy and monitoring relatively cheap. Since I was last here in 2013 a series of red-pained rocks have been placed linearly in a strict grid across the floor of the Stephanos crater and signs warn that because they are part of the monitoring programme moving them incurs a €20 fine. Not the worst scenario.
Most Greek islands attract visitors to their beaches. Not Nisyros. People flock by small boat for day trips and are whisked up to the rim of the caldera on a coach and then down inside. It’s a bit strange seeing the place treated like a theme park especially as people seem to have no sense that while measures are taken to regulate theme parks in the interests of safety there can be no control over an active volcano. They teeter down the rough path and prance across the crater floor in flip-flops, boiling water, steam and sulphur gas hissing up around them. The only nod to health and safety is a notice at the top of the path saying that you go down at your own risk and this year there is an area of especially large fumaroles with a string fence around it in the centre of the crater floor.
Brief history. Nisyros, at the eastern end of the ‘Aegean Volcanic Arc’ blew its top a long time ago (estimated at 160,000 years). Before then it was estimated to be double the height. Longer ago still it was part of an even larger volcano which encompassed Kos. Between the two is now open sea with smaller islands including Yiali comprised largely of pumice (being quarried away by Lafarge to meet the industrial needs of the world) and Strongyli which is smaller but rising. Slowly.
Nisyros is almost circular with a hole in the middle. The caldera floor, about 4 kilometres across, is some 100 metres ASL at its lowest but within that the Stephanos crater drops vertically another 25-30 metres.
(An apology here. I referred in the last post on the blog to the major crater on Nisyros being Alexandros. Well, of course it isn’t, it’s Stephanos!!!! Mental aberration, confusion between Alexander being Great – Megas Alexandros in Greek – and the size of the crater.)
Most of the tourist interest focuses on Stephanos because it’s the biggest and the coaches park right alongside but it’s by no means the only location of volcanic activity within the caldera.
Nisyros is classed as an ‘active’ volcano and an assessment published in 2010 concludes that in comparison to US volcanoes Nisyros is in the ‘Very High Threat’ category (see). The last major eruption was in 1888 but “more recently, in 1996–1998, Nisyros experienced a volcano-seismic crisis, accompanied by ground uplift of more than 10 cm, indicating a period of unrest”. That seismic activity, recording 5.5 on the Richter scale, damaged 30 houses in Mandraki a few kilometres away on the coast. In 2001 or 2003 (accounts seem to differ) a tremor opened a fissure up to 6 metres deep in the floor of the caldera. The magma chamber under the island is only 3-4 kms deep and still rising.
Indications of seismic activity are confined to the main caldera at the centre of the island but there are other smaller caldera which appear dormant. Within the main caldera activity isn’t limited to the main Stephanos crater but is also found in a number of smaller craters including Megalo Polyvotis and Micro Polyvotis and at various other points around the western end.
That volcanic activity continues is clear from the many fumaroles which emit sulphur gases, crystallising out in weird and wonderful bright yellow encrustations. The temperature of the fumaroles has been increasing, apparently from 98oC to 103oC in 2004. Many years ago I put my hand above one and it was …. uncomfortably hot. Foolishly I did the same again recently. I can confirm it was hotter but couldn’t put a precise figure on the difference!!! Just “ **** OWE! Stupid fool!” There seem to be more sulphur-emitting fumaroles this year than the last time I was here in 2013 though that may be memory playing tricks.
There is also boiling mud and water, though these are less in evidence this year than previously. However water flows hissing out of the ground below an almost microscopically thin crust at well above boiling point and you need to be careful not to linger too long in some areas. Feet can become painfully hot while dallying with a camera.
Not as evident but still a sign that activity continues, are the thermal springs which emerge at various points around the perimeter of the island. Most famous historically is the one at Palloi to which Hippocrates (he of the Oath) who practiced and taught medicine on nearby Kos used to send patients for a cure. Now patients are sent to the establishment at Loutra. You can’t pay to go in as a tourist attraction, you have to be referred by your doctor. At Hochlakos beach there is a rope for non-swimmers to pull themselves out over an underwater spring. At Avlaki there are springs within the tiny protected harbour left by failed industrial activity.
What is it that draws people in their hundreds to spend time and money to walk on the floor of an active volcanic crater? There is no doubt that there is a buzz from knowing that the ground is grumbling, boiling away inches below the sole of your sandals … and may decide to belch at any moment.
Now and again I walk up to one of the non-active calderas at the millennia old deserted settlement at Nifios and sit on a rock looking straight down into the Polyvotis craters steaming away far below and think “wouldn’t it be great if it blew while I’m here”. I may not survive the experience but what a great last memory ….. and what great photos.
The photos below are examples of the continuing volcanic activity of the island. More to follow on the rocks and the settlement history
Sulphur crystals around a large fumarole looking across the caldera to the Polyvotis craters and the highest point of the caldera rim, Oros Diavatis
Some fumaroles produce small tubular crystal shapes
Close-up of the crystals. Click to enlarge and look closely and you can see drops of water dripping off themClose-up of the crystals. Click to enlarge and look closely and you can see drops of water dripping off them
An area of the flank of a crater steaming with the sun behind
Close up of one of the fumaroles emitting the vapour
Some of the fumarole openings are large and disappear into the depths of the ground
Boiling mud
Difficult to see but tiny drops of boiling water shoot up out of the ground where the thin crust has been broken.
Looking across the crater floor of Stephanos with the red-painted matrix of marker stones
Part of the near-vertical wall of the Stephanos crater
More sophisticated monitoring equipment in the middle of the caldera
The thermal spring in a cave at Palloi, used since ancient times for healing
Perched on a rock high above the craters waiting for the volcano to blow
x
Barry's Ramblings 
thanks! I had the luck to visit the volcano on a quiet evening in July. The marker stones were not there yet… and all day tourists had long gone, so it was marvellous. I’ll post some pictures once my decent computer is back from repair… Thanks for sharing your love and impressions of Nisyros!
I drop down into the caldera and one or more of the craters every 2 or 3 days. The other days I walk around the rim. I find it mind-blowing and very pleased that you enjoyed it too. I time my visits to the caldera to be between 12.00 when the first coach loads of day trippers have left and about 13.30 when the second lot arrive. Couple of times I’ve been the only person in Stepanos. Look forward to your pictures
we visited it around 18 o’clock – everyone had left. For about 10′ there were two families, but they quickly left, leaving the hot floor for us. Wonderful – and I wish I could go back every week 😉
One day, I will. 🙂
Oh no Barry!!! Aksel an I are having very much respect for natures kraft.,,, Maybe you remember we told you that our house was struck by lightning many years ago ? Now we do not know if we dare to visit Nisyros next summer…Anyway we still visit Tilos…And hop to see you too 🙂
Hi Barry,
I just came across your interesting blog and had a few comments and corrections to share…
I am Dr Helen Kinvig, a volcanologist that has been studying, montoring and working on Nisyros for over 7 years. (I am also the author of the paper that you quoted which assessed Nisyros to being a ‘Very High Threat’ 🙂 )
I’m afraid that I must correct you – GEOWARN do not currently monitor Nisyros volcano – they have not measured activity on Nisyros in over 10 years! In fact, until I set up my equipment last year there were no working monitoring stations on Nisyros. I am the person responsible for the red marker rocks that you saw in Stefanos Crater, and the equipment that you photographed in the caldera was part of a network I set up on Nisyros and surrounding islands last summer. It is always disheartening when others are given the credit for my hard work 😦
My station that you visited and photographed in the caldera has had a GPS and seismometer recording activity here for the past year – I brought them here from the UK after I noticed that the volcano was showing unusual signs of unrest last summer. The equipment was provided to me by NERC on an Urgency Loan, and the University of Liverpool paid for the monitoring campaign. The stations were returned to the UK a few weeks ago.
Monitoring Nisyros is neither easy or cheap – If only it was! Ideally, there should be a full monitoring network on the island to keep the population safe, but there are many financial and political challenges involved and so sadly it remains under-monitored and under-funded. But I am trying to change this, and I have big plans to help the island…so watch this space!
I am extremely passionate about the island and it’s residents and so I have kept a close eye on the volcano for many years now, because I feel this is such an important cause. I have been working hard to improve the safety, education and monitoring efforts on Nisyros, e.g. from putting up the fence in Stefanos crater to creating hazard and evacuation plans.
I recently left my post as a university lecturer in Liverpool, and am now living in Nisyros and focusing my efforts on improving this situation – I continue to collect data and make observations every week, paying out of my own pocket to do so – because someone needs to be doing it!
You say that you noticed some changes since you last visited Nisyros in 2013 – I would LOVE to hear what your thoughts on this are – I don’t think it is just your memory playing tricks….. Are you still on Nisyros?? If so, maybe we could meet for a chat??
You may also be interested to know that the Nisyros caldera forming eruptions actually occurred only ~45,000 years ago. However, 160,000 years ago was the huge eruption that generated the caldera between Nisyros and Kos (Kos Plateau Tuff eruption). At this time Nisyros had only just become an island – before then it was still a submarine volcano.
I hope that this information is useful/interesting to you. If you would like to know anything about the volcano then please feel free to email me at nisyrosvolcano hotmail.com
I am also currently building a website ( http://www.nisyrosvolcano.com ) that will provide information about the volcano and the research done here.
Cheers,
Helen
Hi Helen
Thank you for your corrections and additional information. Much appreciated.
I do my best to assess information on the internet but often find it difficult to put into chronological context and to know who is doing what. I have come across your work and been much impressed by it so I therefore regret not according you appropriate credit.
I would love to meet up for a chat but unfortunately am back in the UK now. It’s too early to be planning for next year but I certainly hope to spend a good amount of time on Nisyros and do more exploring. I looked at the possibility of renting a house on the island for the summer a couple of years ago but couldn’t track down anything suitable. There are far fewer properties for rent than on Symi where I have rented for 3 years now.
When I do come back I would love to meet up and, if it would be useful, perhaps I may be able to give a hand with your work. I did one year of geomorphology in university so am by no means an expert but I am a reasonably proficient dogsbody. I can certainly hump rocks around a wield a tape-measure.
Now we are in contact, anything else I write for the blog on volcanology I will check the accuracy with you first. I know what you mean about the lack of awareness of the potential dangers. Since a arrived home I read an MSc dissertation on the subject which seems to me to make some salient points. I spent some years working on the planning implications of hazardous industries and worked with the local authority Emergency Planning Officer who had put in place plans for all sorts of potential disasters. It seems that this concept doesn’t seem to present on Nisyros.
Thanks again for your comments and hope we can meet up next year.
Best wishes
Barry
Hi Barry,
Thanks for your reply 🙂
Thanks also for your offer of help in the field – it is always great to have company and a helping hand so I may well take you up on that!!
I think I know the MSc you speak of – it did indeed make some good points, but it is sad that the opinions and level of understanding has still not improved here in the ten years since it was published. The report I am writing is similar in nature to this MSc but intends to go into further specific detail and quantify the risks here.
I am creating a hazard map of the potential dangers on the island and will present my suggestions for an emergency plan. I would be very keen to hear your thoughts on the situation and any advcice or ideas you may have from your work experiences. Maybe I could send you a copy before I present it to the government?!
You have my email address – if you could send me a contact address we can exchange ideas 🙂
Thanks and best wishes,
Helen