2015 means one thing for me at the moment, I am currently 3 months into my third year as a PhD student, which means I only have 9 months left to write my thesis, I guess I should get writing sometime soon then...
Here I am, writing this blog post, after an extremely busy Christmas period involving AGU, a holiday in Colorado and the VMSG conference in Norwich. In my last post (Sightseeing in San Francisco before AGU) I blogged about some sightseeing I did involving visits to Muir Woods and the Golden Gate Bridge. In this post I said that Alcatraz really didn't look that far away, insinuating that it really should have been easy! It turns out, however, that the tides are so strong it would take a miracle to time the crossing correctly. Indeed, there was a group who presented at AGU, who modelled the flow conditions on the night of the infamous escape and concluded there was a very small time window to enable successful escape! A summary news article can be found here. Anyhow, I managed to get a bit more sightseeing done in San Francisco, including a group of noisy seals at Pier 39, a submarine (a common theme from my overseas conference visits - and all by mistake!), and a closer view of Alcatraz (all in the pictures below).
AGU is certainly one of the biggest conferences I have been to so far and my first in North America. The poster halls (above) were of very grand proportions. I certainly enjoyed the afternoon poster sessions along with beer on tap which really made going round and discussing peoples work a relaxing and productive experience. The exhibit hall was also present at a significant scale, with companies such as NASA and Google giving demonstrations of their available technology and techniques. There was even a full-size model of a shuttle type craft, but I cannot recall the model - maybe shuttlex. I gave my presentation on the Wednesday at the conference, and for those young researchers and students who have given a presentation at EGU/AGU (or any conference really) before will know that the nerves can build up a bit! AGU is certainly one of the most tiring conferences I have been too as it is pretty full on for 5 days but something I have learnt from previous conferences is that you don't have to go to everything! In fact, you can be much more productive if you don't, it's important to set aside time to reflect on what you have heard or follow-up on any new connections.
After a thoroughly relaxing break, it was straight to VMSG in Norwich for a much smaller but equally valuable conference. Indeed, these conferences can sometimes be more valuable, especially if the conference is of a relevant theme. I must admit I was a little skeptical of a conference in Norwich, mainly because of the reputation the city has within the UK! However, it was a very well-organised event in a unique venue. Although, for some inexplicable reason the vast majority of restaurants and pubs seemed to be shut on the Monday - importantly the Belgian Monk pub which was reputed to serve good food and even better Belgian beers, oh well, till the next time. Instead we found a very nice vegetarian curry place. The conference dinner this year was at Norwich City FCs football ground, Carrow Rd, and it was certainly a very cool location for a dinner - although I was a little disappointed that Delia herself didn't come out of the kitchen gesticulating her scarf around shouting "let's be 'aving you!".
2015 means one thing for me at the moment, I am currently 3 months into my third year as a PhD student, which means I only have 9 months left to write my thesis, I guess I should get writing sometime soon then...
Here I am in San Francisco before AGU 2014, doing a little bit of sightseeing. I am staying in a fantastic hostel not too far from Union Square. Heading out yesterday morning to have a quick look around the city, I felt a little bit out of a place and a little bit like a gate-crasher! The reason? Half the city were dressed as Santa (some had made a better attempt than others)! Apparently, I had stumbled across the yearly event known as SantaCon. I have never heard of this before but the general idea seemed to be one large bar crawl - shame I didn't bring that Santa suit I have hidden away!
In the afternoon, I decided to head over to see Muir Woods via a certain Golden Gate Bridge (on the recommendation of someone in the department). Muir Woods is home to some of the tallest trees in the world - the redwoods. It's a pretty cool little national park (if you have read other blog posts you will see that I have been to a few others in the US), a little bit hidden and out of the way. If I had had more time there are a network of trails around the hillside with views of the Pacific ocean if you get to the top - something for my next visit now I know that it's there. Google Earth/maps really doesn't do the view from the bridge into and out of San Francisco bay justice. Although, looking at the distance between Alcatraz and the mainland, it doesn't actually look that far. I am sure it would be different if I was the one doing the swimming (I am guessing it might be quite cold too). Today, I am off to Fisherman's Wharf to get some nom and have a look around.
It has certainly been a while since my last blog post - it's getting to that time in my PhD where I am coming towards the end of data analysis (and collecting new data) and starting to think about the layout of my thesis. I have been so busy that I forgot completely about blogging. Anyhow, it always helps to have something to blog about, AGU and San Francisco the perfect example! On Wednesday I am presenting on some of the work I have been doing with observing and modelling (in the lab and computationally) slug driven activity. The abstract of this work is posted below.
Abstract: The study of single gas slugs in volcanic conduits has received a large amount of focus within the literature. However, the more complex behaviour associated with the rise and burst of multiple slugs has yet to be considered in detail in a volcanic context. Here we combine observations and analyses of such activity using a three-pronged approach consisting of existing gas mass data collected during rapid slug driven activity at Mt. Etna, scaled laboratory analogue experiments, and computer simulations using the Ansys Fluent® fluid dynamics software. Particular focus was applied to the process of coalescence and wake capture during slug expansion and rise. The results indicate a variety of potential features and relationships, including: promotion of coalescence at distances further than predicted wake lengths, approximate maximum gas volume fraction and minimum magma viscosity values for the occurrence of stable multi-slug activity, and in the laboratory regimes a series of linear trends are associated with overall gas volume fraction and burst volume. A previously observed phenomenon at Mt. Etna, whereby larger slug bursting events are subject to a longer repose period prior to the following event, than smaller events, is also evident in the lab setting. By combining all acquired and modelled data, we derive an approximate relation, using existing formulae for slug base rise speed (Viana et al. 2003) and wake length (Campos and Guedes de Carvalho, 1988), to describe a minimum repose period which is likely to follow the burst of a slug at the surface. The outlined work has significant fluid dynamic implications for possible magma and conduit properties which can allow multi-slug activity at volcanic targets.
With all the rigmarole surrounding what may or may not be happening at Bardarbunga, I thought I would put together a little guide of where to get RELIABLE information and comment. The main source of reliable information is, obviously, from the Icelandic Meteorological Office (IMO), update page here. The IMO really is the best and only source needed - primarily because they are the experts on Icelandic volcanoes and how they may or may not behave! For a detailed description of the area experiencing the unrest see this report on the volcanic system.
As with all volcanic activity there are a number of potential outcomes (for information on these see the IMO website update for the 26th August at 15:45), as such, any blogs or posts which pertain to one exact event happening are unlikely to be trusted! As always though the Eruptions blog by Erik Klemetti is a good and informative read.
There are also quite a few nutters on Youtube these days, so I would be very careful what you watch there.
Below is the twitter feed for the hash-tag Bardarbunga, which, among random posts, should show the most up to date news. Tweeters to look out for are @HTuffen, @Sim0nRedfern and @subglacial. This is of course not an exhaustive list! Don't forget to keep an eye on the webcams too! Links here and here, (the former link does not currently seem to be operational).
One of the fantastic things about driving round the US, especially in a state like Colorado is that there is often something unexpected round the corner. Originating in Denver we drove over the Rockies using US 285 (through a little place called South Park consequently - not many cartoon characters loitering around though!), then hitting the intersection at Salida we travelled west on highway 50. On the map, just before Montrose a small national park called the Black Canyon of the Gunnison was listed, having been in the car most of the day we thought why not take a look! It turned out to be an absolutely fantastic stop with fantastic views of a canyon filled with dikes here, there, and everywhere! The lighter coloured dikes here are pegmatite cutting into Gneiss. The park is surrounded by mountainous regions including the San Juans and the Elk mountain range. One small note, on entering the park we were all expecting to see a dark black canyon (e.g. as dark as some basalts), however, it is certainly more of a dark-to-light grey (although, it may turn a darker colour when the walls are wet...). Black Canyon of the Gunnison does have a much catchier feel to it than - Greyish Canyon of the Gunnison!
We continued the journey through the San Juans on the million dollar highway, which is one of the most beautiful mountain passes I have been through, on our way to Durango. By the way in Durango there is an excellent restaurant (called Durango Brewpub) which served excellent food and excellent beer too. I will give fair warning though the chilli beer was certainly hotter than expected!
OK, so the next location was extremely interesting, but not for the geology, the location? Mesa Verde national park (picture below of the Cliff Palace). Mesa Verde is the ancestral location of a number of current Native Indian peoples. The fantastic thing about these people is that sometime in the 1100s/1200s they started to move into these cliff dwellings underneath the overhangs (as pictured below) in response to changing environmental conditions. These really are worth a visit and I would thoroughly recommend the guided tours by the national park rangers to Cliff Palace, Balcony House and the Long House. During these you will learn a lot about the peoples who lived there, why they moved down and how they survived. Credit must really be given to the rangers who are very knowledgeable and really seemed to care about the location and the people. We were lucky to have three different perspectives from three different rangers with three different backgrounds: the first an archaeologist by training, the second an anthropologist, and the third a historian.
One more night in Durango and then the final stop on our trip, on the way back to Denver, was at the Sand Dunes National Park. This really is a surprising location, mostly because you really don't expect these rather large sand dunes (the tallest in North America) to appear out of nowhere! The picture below probably doesn't do them justice. On a vaguely volcanic note, theses Dunes are location a small distance (~100 miles) from the site of possibly the largest known volcanic eruption in history - that which created the La Garita Caldera. Climbing to the top of these dunes which are around 750 feet high was certainly harder than it looked!
This (brief!) post spawned from a series of recent video and photo discoveries from Twitter and YouTube. The first time I observed a dust devil was at Vulcano only a few months ago. Although, I suppose it should really be called a gas devil as it was the condensed volcanic gases which made the phenomenon visible! The photo on the right of Vulcano illustrates this and the video at the very bottom shows the formation and development of the "gas devil". Interestingly enough a "gas devil" was seen emanting from almost exactly the same location several times over the course of the few days we spent at the summit.
This leads us to the question, what forms them? I am by no means an atmospheric expert but here goes... The key component is the heating of the ground which creates a large enough temperature difference between the air near to the ground and the air above it (i.e. creating a density difference). This then starts a process of convection (not an unfamiliar topic in volcanology, a similar process likely occurs within volcanic conduits). Following this all that is needed are appropriate wind conditions to push the dust devil into a vertical position and viola! This process probably occurs a lot more often than we observe, as it is with the entertainment of particles that dust devils become visible! A couple of good explanations (which helped a lot!) are included here and here (along with a good graphic in the latter one).
So taking this new found knowledge and applying it to a couple of volcanic situations... In the case of Vulcano the heat comes from both the incoming solar radiation and potentially the heat of the fumarole(s) with a nice side wind over the edge of the crater. In the case of Sinabung (video below) it is entirely possible that the ground (and air) is super-heated by the pyroclastic density currents which have just rolled by, leading to some fantastic examples!
Many thanks are due to Oliver Lamb and Rudiger Escobar Wolf for links to photos of Colima (click on on Oliver Lambs name) and Sanitaguito (photo to the left). Also to Luca D'Auria for the initial post in a Facebook group. Dust devils have also been observed at volcanoes such as Mt. St. Helens and some fantastic examples at Sinabung, which are so good I had to included the YouTube video below. Of course dust devils such as this don't just occur at volcanoes and have also been observed on Mars!
I love a disaster movie, even cheesy ones with volcanoes and bad science in them...In fact one of my favourite volcano related disaster movies (there aren't that many to choose from I know!) is Dante's Peak. What isn't there to enjoy about a volcanologist who nonchalantly waltzes and swaggers his way round or over volcanic obstacles and phenomena (even though plausibility is certainly questionable!). I suppose it also helps that this particular volcanologist is associated with roles such as James Bond, which all aids to "sex and glammer up" what the vast majority of volcanologists really do! Long story short, it was no surprise that I went to this particular movie. Being A Game Of Thrones (GoT) fan too (the lead character "Milo" is also "John Snow" in GoT) it wasn't much of a hard decision.
The film, of course, revolves around the eruption of Vesuvius in AD 79. Volcanologically and historically this eruption was important for a number of reasons, including it's complete engulfment of Pompeii and other nearby settlements (e.g. Herculaneum) and the unprecedented account of the eruption by a nearby observer - Pliny the Younger. Having never read the accounts of Pliny this was one of the first things I did. Pliny recounts the eruptions in two letters to Tacitus, a prominent historian in his own right. Pliny at the tender age of 18, witnesses parts of the eruption himself and recounts other parts from sources at the time. In these letters, Pliny remarks on significant Earth tremors leading up to the eruption, which certainly were present in the film. He also makes references to the receding of the sea and a significant amount of ashfall - which eventually kills Pliny the Elder. On a side note he also gives a fantastic description of the rising of a buoyant plume.
So, scientifically, what was questionable in the film or didn't occur at the time? Pliny the Younger does mention a slight recession of the sea, which certainly suggests that a Tsunami did occur, although, I have found/heard no mention of the gargantuan waves depicted in the films. Trawling the internet I tried to find whether there was a consultant volcanologist employed on the film but was unfortunately unsuccessful. As always I am a little behind trend and you can find another summary of the movie here on live science. In this overview, they also mention the volcanic bombs, their absence in any evidence and also the size of any Tsunami.
It was slightly disappointing that the film didn't incorporate more of Pliny, oh well! I would certainly recommend reading the letters of Pliny in their entirety, whilst the majority are related to his doings in the senate, they really are a fantastic insight into the Roman world - there is even a Ghost story thrown in!
I had a bit of spare time in the field recently and decided to do a spur of the moment impression of Sir David Attenborough...(with the greatest respect to the man himself of course!)
Vulcano is one of the most fantastic destinations I have had the chance to do fieldwork so far. Combine an easily accessible summit (on the right), persistently active fumaroles and amazing summit views, with great food and the result is a most enjoyable and productive field session. Another great thing about Vulcano as a target for remote sensors like me is that it is relatively accessible all year round (subject to somewhat erratic boat timetables) and it is less subject to inclement weather conditions. This is something that nearby volcanoes Etna and Stromboli suffer from greatly especially during winter months. However, this is certainly not to say that Vulcano doesn't have its challenges when making measurements because it certainly does! For this particular session we were taking a variety of spectroscopic measurements of the summit fumaroles (first photo on the right) using ultra-violet cameras (see Tamburello et al. 2011 for previous measurements at Vulcano) and transecting the fumaroles using a MultiGAS unit (see Aiuppa et al. 2005; Shinohara, 2005). A MultiGAS unit sucks in surrounding air through a tube and analyses for the concentration of a number of volcanic species (e.g. sulphur dioxide, carbon dioxide etc), it can do this at an extremely high resolution of approximately every 2 seconds.
To continue with my previous thought, what are these challenges when making measurements? Well first and foremost when using ultra-violet and other spectroscopic systems, for the most accurate of measurements a number of conditions need to be met:
To the left is the merged plume of a number of the fumaroles early on one of the mornings. As you can probably observe, the plume is a little too condensed at this stage...but a few hours of waiting and conditions improved to become almost perfect (as above). In the centre of the image you can just about make out a solitary figure clad all in white. This figure is just about to enter the plume and perform a transect of the upper crater terrace fumaroles using a MultiGAS unit. When transecting the plume it is necessary to where goggles and a gas mask to protect against the high concentrations of toxic gases. The first thing you notice when you reach the vicinity of the plume is a faint rotten egg smell (hydrogen sulphide). Anyone who has stood in the vicinity of such gases will know that one of the first noticeable effects, even at relatively low concentrations, is the irritation of respiratory tracts. This can often result in quite a bit of coughing!
Of course Vulcano is a great place for more than just the summit fumaroles, previous historical eruptions (e.g. the eruption of 1888) have thrown up some quite spectacularly sized bombs with a large number of them the appropriately named bread-crust bombs which are scattered around the place. After stumbling across a book: Vulcano, Tre Secoli Di Mineralogia (Three centuries of minerals). in a little restaurant called Maurizios (which I highly recommend!), I learnt that there were in fact minute amounts of gold found in the fumaroles of Vulcano. However, don't pack your bags, and shovels yet, the amounts present would certainly not be enough to make you rich very quickly! In the photos at the bottom of the post you can see the plume of Stromboli, taken with a canon 300 mm zoom lens and a couple of the surrounding Aeolian Islands. You can find a few more photos in this section on my website!
Thanks to Tom for inviting me to contribute this blog-post. I should start by telling you a little about me and how I know Tom, so here goes. I am a PhD student at Royal Holloway, University of London, researching volcano-tectonics and specifically the mechanics of caldera collapses. Like Tom I also studied for a Master’s degree in Volcanology and Geological Hazards at Lancaster University, although we did not meet at Lancaster. I first met Tom in May 2013 for a NEMOH organised field school at Stromboli volcano; where we jointly experienced an unfortunately unforgettable, and particularly rough boat back to the mainland of Sicily. I can highly recommend that if the captain of a sketchy looking boat offers to get you off an island when none of the main companies are willing to, think again!
So, Tom asked me to write this post as he heard that I was working at a really fascinating and important volcano in Greece. The volcano in question is Santorini, which is a particularly famous stratovolcano in the Aegean ocean. The volcano is famous partly because around 3500 years ago the island experienced a huge caldera forming eruption, which is believed to be associated with the demise of the Minoan civilisation. Deposits from the various phases of the eruption can be seen straddling almost the entire circumference of a north-south elongated caldera, which measures approximately 10 km in maximum diameter, several hundred metres in depth and is centrally filled by ocean. In fact, at least three huge eruptions, ~100 thousand years, ~21 thousand and ~3500 years ago contributed to the shape and size of the current caldera. The global impacts of the Minoan eruption have often been overestimated (see the article of Pyle, 1995), however in terms of volume this eruption is up there with the biggest of the past 10,000 years. Active volcanism in Santorini is now constrained to a small island named Nea Kameni, located almost in the centre of the caldera. This resurgent volcano has been the site of several predominantly effusive eruptions, the latest of which occurred in 1950. Importantly, the island of Santorini lies on top of two north-east to south-west trending faults, one in the north of the island is called the Colombo fault and the other which is believed to be associated with the current phase of volcanism lies directly under Nea Kameni, and is named the Kameni fault.
OK, so what was I doing in Santorini? The answer is looking for and studying dykes in the caldera walls. Just so you’re up to speed, a dyke is a magma-driven fracture through which all volcanic eruptions must be fed. As such, it is really important to know the conditions for dyke propagation in a volcanic edifice. Luckily there are many fantastic geological locations (e.g. Iceland/Tenerife) around the world where geologists can see deep inside ancient volcanoes. In doing so it is possible to observe that many dykes (if not most) never reach the surface, and therefore never contribute to a volcanic eruption. They become arrested.
Santorini is a stratovolcano made up of many layers of contrasting mechanical properties; for example, stiff lava flows and comparatively compliant layers such as ash, volcanic tuffs and breccia’s. So it offers a great opportunity to try to understand how dykes pass through these individual layers. Specifically, I went into the field to take measurements on the thicknesses, directions and compositions of individual dykes. The walls of the caldera are very steep and largely inaccessible, so most of my work was conducted from a boat, which was a really cool experience. The data is important for me because I am trying to understand how calderas form in different volcanoes. I am using the propagation of dykes as a proxy for the propagation of caldera fractures, because presumably the fracture which created the current caldera must have passed through the same materials with which these dykes also passed.
In 2011, Santorini experienced an unrest period characterised by elevated levels of seismicity and uplift (see Parks, 2012 for details). Such signals are most likely associated with magma being transported as dyke from great depths, to recharge a shallow magma chamber. When and why a magma chamber ruptures and sends a dyke to the surface is still a reasonably poorly understood phenomenon. So the important question at most caldera volcanoes is: when does a period of unrest lead to a volcanic eruption? It is a difficult one to answer!
As well as gathering data for my PhD I also took the time to help out at the run-off erosion intensive field-course organised by the University of Athens. Sandy Drymoni and I ran the course’s final day visit to Nea Kameni, where we introduced some basic volcanological concepts and described some of the islands features. This was a very rewarding and enjoyable experience. The previous day I also had the opportunity to meet the mayor of Santorini at a visit to the Minoan ruins at Akrotiri. Although I wasn’t able to question him about the island’s volcanic preparedness, this was partly out of courtesy, but mainly because we didn’t speak any of the same languages.
I will now use the data collected from this fieldwork as an input for numerical models using the structural mechanics module of a program called COMSOL. In doing so, I will try to understand the stress conditions required for dyke propagation; caldera formation and magma chamber rupture in different types of volcanic edifice.
The receival of a last minute NERC Impaft Fund has meant a mad dash to be ready for a sampling session at Vulcano. The volcano which all others take their name! I am quite excited about adding another volcano to my growing list.
So....what do I do to prepare for fieldwork. One of the first things you do is check all the main equipment is working! In this case, I am developing a new technique which means a brand new Matlab Application finished the Friday before I leave! Hopefully its suitably free of bugs! Next I list the equipment I need, check I know how to use it and I have plenty of spare batteries.
As always, last minute clothes packing and as always I forget one thing...this time it was deodrant...
Vulcano is one of the Aeolian Islands (which includes Stromboli, Lipari) and is fantastic for remote sensing for the majority of the year because of generally good measurement conditions and persistent fumaroles at the La Fossa Crater! Its easily accesible by boat from Milazzo.
So, here I am writing this blog on the pier in Milazzo after surviving two days of driving in Palermo (one Italian told me if you can drive in Palermo you can drive anywhere) and the North coast of Sicily! I am going to try and do a little bit of tweeting/blogging from the field if I have time!