Tag Archives: Science

Apocalypsathon; Post 21/12/12 Appeal…

I think Tyler Mannison found this one...

I think Tyler Mannison found this one…

Send your urgent and much needed donations for those poor unfortunate endotheworlders who were not wiped out (they must be devastated) to schteve’sschwissbanking.ch

Please spare a thought and a dime for those not raptured up to heaven in the recent non- apocalypse; give generously, it’s nearly christmas after all…

since this didn't happen everywhere all at once...

Since this didn’t happen everywhere all at once…

I intend to set up a refuge high in the hills of La Gomera with a nice piece of (terraced) land and a look out tower; we’ll charge post 2012ers top- whack to come and contemplate… Me n’ Lizzie will be there most of the year looking after the goats and generally taking care of the place (and going for long walks and jaunts to El Hierro and stuff.) So once again Volcanocafers please dig deep for this very worthy cause…

Somewhere like this, Pico del Teide is in the distance...

Somewhere like this, Pico del Teide is in the distance…

http://upload.wikimedia.org/wikipedia/commons/thumb/a/a5/La_Gomera_1.jpg/1280px-La_Gomera_1.jpg

But seriously, and since we are still here; a genuine appeal (and some of my highlights):

This rather special place was started by Carl and Ursula after a group Volcanoholics decided they wanted their own place with their own rules… Those that wanted to go multidisciniplary, collaborative and friendly came here and (boy!) the discussion was, and still is, far ranging… The Welcome page and blog rules are here:

http://volcanocafe.wordpress.com/2011/11/15/volcano-cafe/

The average post rate is ~ one every 3 days, (that includes before and after Carl statistics…) some volcanoblogs manage more, but usually these are brief updates. What we get here are crafted pieces, made by amateurs in their spare time…

The hit rate is around ~150 visits per hour; this doesn’t include dragon visits…

I won’t lie to you; a blogpost can be quite a bit of work, depending on your skills… Carl once mentioned that he could write a 1200 word opera review in 20 minutes, and Geolurking seems to be able to get something revolutionary on tectonics done in only slightly more time…

Birgit deserves her own paragraph; she can research, compile, edit, post and get an intelligent layman up to speed on a particular subject in less time than it takes a crocodile to swallow an unwary victim!!!

Me? I’m at the other end of the scale; maybe 20 hours work on Teneguia Technicalities and Context, but that did include editing with wordpress which was a first for me… Don’t let me scare you, I can be quite ambitious…

I am asking everyone to keep the posts coming; think of it as an extended comment and you will do fine…

This one's for our resident geologist...

This one’s for our resident geologist… The little engine that could x

http://upload.wikimedia.org/wikipedia/commons/thumb/d/d2/Snowdon_Mountain_Railway_No_6.jpg/1280px-Snowdon_Mountain_Railway_No_6.jpg

Visits to volcanoes “a la Ukviggen” are always popular; (Mount Snowdon anyone? The narrow gauge, rack and pinion railway is the only one of it’s kind in the UK.) as are summaries of your favorites; (Karenz on Sakurajima is a very good example.) and memories of eruptions that were special to you; (Bobbi’s piece on Redoubt is a classic, and don’t forget Newby’s uncle on Erebus.)

Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula April 21, 1990 (R. Clucas)

Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula April 21, 1990 (R. Clucas)

For the more ambitious how about an original piece of research? (Irpsit wrote a fascinating series about a big hole!!!) Controversial stuff is great, got an alternate theory? (Peter Cobbold on El Hierro is excellent.) What about something inter- disciplinary? (Diana Barnes on Scheeps helping to revive volcanic badlands is wonderful!) Technicalities more your bag? (Wagabond on marine seimic sounding; great insights.) Plotters, hows about “beefing up” a special plot? (Plotting for Beginners 2 may get done one day, but feel free to jump in!!!)

One of Birgit's SEM images of material from El Hierro

One of Birgit’s awesome SEM images of material from El Hierro…

If none of these inspire how about something outrageously off topic for the Scheeepy Dalek?

Nothing is like the smell of a Motorcade in Depresneyville in the morning. Remember that when people shoot at you, they just wish to greet you welcome to Ukraine.

Nothing is like the smell of a Motorcade in Depresneyville in the morning. Remember that when people shoot at you, they just wish to greet you welcome to Ukraine.

So please, go and do yr research, track down the info on yr chosen subject and write something up… Include the standard Volcanocafe disclaimer and a reasonable list of references; and you’re done…

Posts are best submitted as plain text word documents; attached to an email. Pictures should be separately/ individually attached; most formats are fine but please no psd, crw or nef (they are too big and probably not supported by WP either; they need to be converted first). Jpg, gif, png, tiff are commonly supported formats and will do well.

However; when I asked Sissel about this, she said: “Just send it, I will edit what is neccessary!” (another inspirational blogger; remember The Little Prince?)

Have you ever made a comment that you (later) wished you’d saved for a guestpost? Then we want to hear from you; (give us as much detail as possible: approx dates, subject, etc. and we will go digging) dragons can search all 70,000 comments and extract that moment of inspiration…

My top tip (I know it’s environmentally unfriendly) is to print out the papers that you are really interested in; the references for yr article; that kinda thing…

Posts and comments are the lifeblood of the blog, there are (almost) no stupid questions or statements.

So there you have it, no more excuses for not handing in your homework!!!

With Love and Respect,

Schteve x

Links to inspirational articles:

Volcanic Riddles for the Crowd!

Hello everyone!

After a very volcanically unhectic week it will be good to bend the heads over two mind-contorting riddles. I had prepaired a Name that Volcano Riddle, but then Suzie sent me one that was so mind-boggling that I felt like a understudy Riddler.

There is also another instalment of Evil Alan’s mineralogical riddles. This time Alan confesses to his favourite movie.

About the video, a couple of posts ago I wrote about Volcanologists and Geologists playing Lip Banjo. It comes from a geologist friend of mine who described the joy of when he found a brand spanking new mine in Sweden as “Doing splits while playing Lip Banjo”. I got a lot of comments and a couple of emails where people seriously asked how you play Lip Banjo, so, up above is an instructional video for how Volcanologists play Lip Banjo.

Name that Volcano Riddle by Suzie

 2012582 Who am I?

Here are 4 picture clues.

Clue number 1

Clue number 2

Clue number 3

Clue number 4

Evil Alan’s Riddles

I sound as if I should have some connection to Dundee! Mmm, whilst I won’t do you any good, a relative is good on ice!

What am I? To what are the good and bad referring? (3 points to be had)

Good luck everyone!

Update!

Since everyone seems to have gotten sad that the Riddles are riddled out, here is a bonus riddle.

‘Finnish shemale fish, under what watery grave do I rest?’
Name the Volcano, and name the watery grave. 2 points.

CARL

Lusi – The “man made” volcano?

Not all natural phenomena that carry the name “volcano” are caused by the eruption of some kind of magma. A mudvolcano is one of them. Since the 29th of may, 2006, mud and steam are spewing from the earth on the island of Java, Indonesia, leaving  thousands of people homeless. Today, it is still “erupting”. At that time, a drilling rig was in the direct vicinity, and the drilling rig had experienced some problems with the well the days before. On the 26th of may, a M6.3 earthquake occured 250 km to the southwest of the location, with several aftershocks, leading to those problems with the well. So….. Who did it? What caused the Lusi Mud Volcano to form? Was it the oil company, was it nature, are they both to blame?

Let’s start off by mentioning that despite the general idea you might get from watching the Discovery Channel oil and rig shows, drilling a well for oil and gas nowadays is in general a very delicate, well planned and carefully managed operation. Countless rules, regulations, industry standards, best practices and company regulations have to be followed in order to begin or continue drilling operations.

Two of the key things to understand what could have caused this disaster are the management of formation pressure and the design of a casing scheme.

When we are thinking about volcanism, we are in general talking about very high pressured ‘fluids’ that are stored in a magma reservoir, that crack, break, melt and blow their way through overlying formations from their source, often tens of kilometers down. Those fluids can be almost continuous (undeveloped hot fresh stuff, like basalt) or fluids in a sort of matrix of crystals (viscous mush, like rhyolite). When we talk about oil, gas or water reservoirs, we are talking about fluids and gasses that are stored inside the pore spaces of existing rock at some 2 to 3 kilometers down (in this case). Those pore spaces can be very small, like in shale/claystone, or even nonexistent, as in a homogeneous rock salt. Formations that have a large percentage of pore space are generally called reservoirs, because they can contain gas, oil or water that can flow through the rock. Sandstone and carbonate-rocks are the main types of reservoirs that are of interest for oil&gas, geothermal or drinkwater prospectors, despite the recent trends in shalegas.

When we drill down, all pore spaces we encounter have something in them, usually fresh or salt water, sometimes oil or gas, with a certain pressure. This pressure is caused by the weight of the overlying rocks pushing down on it, and sometimes by local geological stress. The deeper you go, the higher the pressure. This pressure can be expressed as an absolute measure, for example 400 bar at a depth of 3000 meters (let’s stick with metric for ease of understanding and calculation). We can also express this as a pressure gradient, a number that stays somewhat constant no matter how deep you go. We know that just fresh water (which has a specific density/gravity or SG of 1.00) will give you a hydrostatic pressure of 9.81 bars at 100 meters depth, so we can calculate that the 400 bar at 3000 meters is roughly equivalent to a hypothetical fluid which is 1.31 times heavier than water. If we would fill our hole from top to bottom with a fluid of 1.31 SG, we would nicely balance the pore pressure at 3000 meters depth to 400 bar, so that no fluids enter or exit the wellbore into the formation. This is the stable situation that is needed for drilling the formation. If the hydrostatic pressure caused by the column of fluid is increased too far above the pore pressure of the rock, the drilling fluid will leak into the pores of the formation, which is called “losses”. If the hydrostatic pressure is lowered too far, formation fluids and/or gas can start rushing into the wellbore, which is called a kick or influx. If a kick goes on without controlling the pressure down in the hole in some way, it can evolve into a uncontrolled flow or even a blowout at some point.

Pressure gradients in formations lie almost always between a hydrostatic gradient (1.00 SG) and a lithostatic gradient (+/- 2.6 SG). In rare cases, the pressure can exceed those gradients. A gas or oil reservoir that has been depleted will generally have a gradient lower than 1.00 SG, down to practically 0.00 SG in some places. On the other hand, some geological processes can cause a gradient greater than 2.6 SG in some extreme cases.

The area seen from the sky. This used to be a place where you could drive through villages and meet people.

It often happens that drilling proceeds through various formations with quite different formation pressure gradients from formation to formation. This poses a problem, because drilling cannot be resumed. If two different formations need fluids with very different specific gravities, there is no right number to choose. The stable condition that is required for continuing the drilling is not possible anymore.  If a formation is expected where the pressure gradient will be a lot higher or lower than the previously penetrated formations, preventative measures have to be taken. A steel pipe, called casing, with a diameter slightly smaller than the wellbore, is lowered into the well all the way to bottom. Cement is then pumped into the void between the casings outer wall and the wellbore to isolate and seal off all the formations that have been penetrated up (down?) to that point. If everything went according to plan, the casing and the cement will serve as a barrier to allow drilling to continue with a smaller drillbit and with a fluid that has the required density for the upcoming formation.

Before a well is drilled, there has to be a complete plan in place regarding the drilling fluids to be used and the casings that are planned to be run. Some wells need only 1 or 2 casing intervals, others need up to 10 different casing intervals because of the changing conditions down in the hole. If several wells have been drilled in the area already, things get a bit simpler, because you have a very good idea which formations you will encounter and you can look at the data from previous wells to see if they had problems with specific formations.

Now, with all of this information in mind, we can start looking at what actually happened in Indonesia.

A drilling spot was picked by the oil company to target a reservoir. The area is seismically active (as everything in Indonesia) and there is an active conventional volcano at 15 km from the drilling site. The area is particularly known for the existence of mud volcano’s, several can be found in the area, all getting their feed of water/mud from the same overpressured carbonate formation that stretches the area. Drilling started and a casing was cemented in place. Drilling commenced with a smaller drillbit and just below the casing, the strength of the formation and quality of the casing and cement was tested by performing a so-called leak-off test. The cement and the formation were confirmed to be strong enough to continue safe drilling.

Construction workers building a dam around the area to direct the flow of the mud.

On the 26th of may, a M6.3 earthquake shook Yogyjakarta, some 250 km away. Right after the quake, 7 minutes later, it was noted that some drilling fluid was lost to the formation, most likely into a fracture or fault. Two aftershocks followed, leading to the immediate total loss of all drilling fluid in the hole. The losses were cured using a special blend of chemicals to seal off the fracture or loss zone, which is a very common occurence in the industry. After this, drilling resumed. A day later, overpressured limestone was encountered, leading to the influx of formation fluid into the well. The influx was “killed” by increasing the density of the drilling fluid until the flow stopped. Barely a day later, mud, steam and gasses started spewing from the earth less than 200 meters away from the drilling site.

So, who or what is to blame? A recent statement of geologists and drilling engineers in the court case points to a human cause. In the statement it is mentioned that the drilling program for the well had not been followed. A casing was planned to be set some 250 meters above the formation that later on provided the catastrophic influx that cracked and broke through the overlying rocks that had limited strength. After breaking through the final sealing formation just above the high-pressured zone, the cap was off the shaken bottle.

Many of the other arguments can be found on the wikipedia page of this event: http://en.wikipedia.org/wiki/Sidoarjo_mud_flow but it goes beyond this post to go into them in detail. Have a read through if you are curious.

The main thing is, that it is very well possible for human beings to have a devastating impact on the surroundings if great care is not taken. This example is probably the best candidate for being a truly man made volcano, although it doesn’t erupt any real lava. As this shows, it doesn’t take magma at 1000 degrees Celsius oozing or blowing out of the earth to do great damage to a village, just a bit of water and mud will have a devastating impact as well when driven by anomalously high pressure.

The main “vent”. It certainly does remind of a shield volcano.

The eruption started off with flowrates in excess of 100.000 m3/day, or more than 0.1 m3 km in 3 years. That flowrate has gone down a bit now, but geologists expect that it can take up to 35 years longer before the flow ceases. Meanwhile, all this material is being extracted from just below the eruption site. Subsidence is already measurable and even the formation of a small caldera is expected the next couple of years. Some 40.000 people have already had to flee their homes, a staggering number that even most large conventional eruptions cannot match.

El Nathan

Chain of Dead Poets!

Amsterdam Island with visible craters.

The Amsterdam St Paul hotspot is one of the weaker hotspots around. It has created the St Paul and Amsterdam Islands, the now active Boomerang Seamount (last known eruption 1995), and an elongated chain of seamounts called the Chain of Dead Poets. These are remnants of the eruptive wake of the Amsterdam St Paul hotspot as the plates move on over it. The hotspot has had 2 episodes of increased activity after it became active. The first period lasted from 10 million years ago to six million years ago. The second period started 3 million years ago and lasts up until today. Amsterdam, St Paul and the Boomerang Seamount have all been produced during this second period of activity.

The hotspot is associated with the South East Indian Ridge and its rift system, and the chains volcanoes show evidence of changing in its chemical composition as the hotspot moved into the SEIR.

Amsterdam Island

The Island is the northernmost of the Antarctic sub-aerial volcanoes. It has had two eruptive centers down the line. Both with visible craters, the younger of the craters are far more visible on the image. Both of the craters are from periods of heightened activity, but later volcanism on the Island has primarily been of the flanking fissure type. Even though no eruption has been witnessed lava samples taken from the flanks of the younger crater shows that the volcano has indeed erupted during the last 100 years.

St Paul Island

The channel into St Paul natural harbour. One should keep slightly to the portside of the centerline of the channel when sailing in. The starboard side is much more shallow. By keeping slightly to portside of the middle you can get a 3 meter deep sailing ship into the natural harbour, well inside of it depth is not a problem, and you are quite safe regardless of weather. Stay away from the mammals on the beach, they are big and mean and are in no way to be compared to people in bikinis.

The island had a large eruption a few years before 1780 in which the predominant caldera formed. Even though the caldera is small for being a caldera it was probably formed by a Krakatoa style eruption starting with a for the volcanic system unusually large eruption with a subsequent magma chamber roof failure that let the ocean water down into the chamber. The ensuing steam explosion gutted the chamber.  In 1780 the vestigial remnants of the caldera wall facing the ocean crumbled and the ocean has during the following years carved out a fairly broad, but shallow canal that is open for smaller sailing ships due to its limited depth of around 3 to 5 meters.

Map of St Paul Island from Wikipedia. Note that the island is very small. The actual caldera is only slightly larger than 1 km across.

The Island is together with Isle du Kerguelen the best harbor in the southern ocean, and many trans-globe sailors make a port of call for repairs, or just general relaxation and landfall.

Boomerang Seamount

Not much is known about Boomerang that lies 18 kilometers north of Amsterdam Island. It rises 1 100 meters above the sea floor, but is still 650 meters below the ocean surface. During an expedition in 1996 they dredged up a lava sample and tested its Uranium/Thorium content. It showed that the lava had been erupted only 5 months prior to the visit.

The Seamount has a 2km caldera showing that the volcano has had at least one substantial eruption and probably have been a bit closer to the surface before.

CARL

A brief update on El Hierro

This image from the tourist bureau gives quite a good perspective on the island of El Hierro and La Restinga. One just need to lift the eyes to see the volcanic edifices looming over the villcage.

As the smoke starts to clear at El Hierro we get a much more detailed picture of what is happening. As data has poured in we can now deduce a few things.

First of all GPS figures today confirmed that this is indeed a fourth bolus of magma coming up from the depth.  The first one in July 2011 started the entire hubbub and in the end caused the sub-aquatic eruption south of La Restinga. A second bolus in January that followed the same path revigorated the ongoing eruption briefly, but was too small to keep up the pressure in the volcanic system and the eruption dwindled to a halt. The third bolus is so far the most interesting, during a few days more magma arrived than during the first one that caused the eruption. The magma arrived at the same place as for the first two (around the Tanganasoga volcano), but then it took an entirely new path and created quite a few earthquakes as it moved towards the western point of the Island. The fourth bolus also arrived at Tanganasoga, and immediately started to move south and slightly downwards.

Image by IGN. GPS data points for the uplift, figures are aproximatly 2 days old.

We still have only one set of data points for the GPS, but since it is visible on many of them it is still credible. What is a good test for if there is actual inflation or not is to check for motion in EW and NS directions. A false read normally does not show that.

The earthquake swarm is very vigorous with more then 100 earthquakes per day. The pattern is still continuing with a south and slightly down dipping motion. We will see if the hard tested village of La Restinga will have to suffer both the knowledge and the feeling of magma moving straight down under their feets.

Image by IGN.

We can also rule out any degassing or actual small eruption, what initially looked like harmonic tremor are most likely small earthquakes, there is no clear signal showing harmonic tremor to this date.

Image by IGN. No harmonic tremor showing on the charts now. So, no eruption, or no de-gassing.

There is no way to know if this bolus will cause an eruption or not. The lack of harmonic tremor says that it will at least not happen within the next 24 hours or so. But, for the residents on El Hierro the same advice is always valid, stay on top of the news.

CARL