Tag Archives: Geology

Volcanic Mishaps 2: Mono Lake, California.

Mono Lake, from Wikimedia Commons.

Tufa Outcrops, Mono Lake.
Image from Wikimedia Commons.

We had 2 weeks in California; after a weekend in San Francisco and some chillaxin’ by the pool in Sacramento; we took the roadtrip of a lifetime. (many thanks Val x) We visited Lake Tahoe, Mono Lake, Yosemite, Mariposa and drove back to Sacramento via Route 49; the gold rush route…

Trees were more my thing in those days, I armed myself with Stuart and Sawyer’s Trees and Shrubs of California; (ISBN 0520221095) bought for $8 in a second hand bookstore in Berkeley and managed to tick off a fair few… Including this baby:

416px-Grizzly_Giant_Mariposa_Grove

The Grizzly Giant, species: Sequoiadendron giganteum.
From Wikimedia commons.

Statistics: 63.7m high (somewhat truncated by a lightning strike, I guess…) Circumference at ground level: 29.5m, Diameter at 1.5 m from the ground: 7.8m, Estimated bole volume: 963m^3 and old enough to have lived through the action described below!!!

It wasn’t much of a mishap, more of an oversight… We were visiting because my girlfriend (at the time) had seen a picture; something like the one above, and had fallen in love with the desolate beauty of the place. So we went and looked around; we saw the tufa rock formed by accretion of materials at hydro thermal vents and exposed when Los Angeles began tapping Mono Lake’s tributaries; the lake itself is highly saline/ alkaline. We saw Black Point, formed under a much deeper Mono Lake 13,000 years ago; now a flattened cone of basaltic debris. We had a good long look at Negit Island; built by several eruptive episodes between 1600 and 270 years ago. We goggled at Paoha Island created by a magmatic intrusion under the lake between 1720 and 1850; it has an exposed section of rhyolite and 7 (count em’) dacite cinder cones! There was a seismic swarm in 1980 including EQs of up to 6mag (estimated, richter scale) and another in the nearby White Mountain fault in 1986.

Mono Lake is not the whole story; to the south there are a series of domes, coulees, flows and craters stretching all the way to the Inyo Craters; many of these were formed in a series of violent eruptions ~600 years ago. When I say violent I mean phreatomagmatic explosions followed by the opening of a 6km multi- vent fissure, pyroclastic flows affecting the Mono Lake area and then (geologically shortly afterwards) a virtual repeat 40 kms south at the Inyo Craters, followed by coulee and dome building!!! The remaining features are thought to have arisen in the last 2000 years. Mammoth Mountain and the Long Valley Caldera are nearby… Quite a piece of volcanic real estate, I think you’ll agree:

The Big Picture...

The Big Picture… Approx 50kms top to bottom.
Wikimedia commons again.

This sums it up pretty well:

http://en.wikipedia.org/wiki/Mono%E2%80%93Inyo_Craters

The mishap? We were walking around in and admiring an awesome, starkly beautiful landscape, which:

“is considered one of the most likely sites for future volcanic activity in the United States”

according to Gates and Ritchie…

and I had absolutely no idea it was even a volcanic landscape until “yesterday” when I was glancing through their book!!!

Schtevie x

Disclaimer: The author is an amateur blogger and has absolutely no quailifications as a geologist or anything of the sort.

The article is not implying that “something is going on” and should give you no cause for concern at this time.

See the USGS website linked below for up to date information.

References

The United States Geological Survey:

http://www.usgs.gov/

Webcam:

http://www.monolake.org/today/mlcam

Inspiration for the article from:

Gates and Ritchie’s; Encyclopedia of Earthquakes and Volcanoes, 3rd edition. ISBN0816063028.

Not really a reference; (I nearly put my back out when I picked it up from under the tree!!!) but destined to be a new favourite:

Encyclopedia of Volcanoes; editor in chief Haruldar Sigurdsson. ISBN 012643140x.

GeoLurking Link Recommendations for the nitty gritty. (Note, all links provided documents even though some are in paywall company sites)

“Monitoring Unrest in a Large Silicic Caldera, the Long Valley-Inyo Craters Volcanic Complex in East-Central California” Hill (1984)

http://link.springer.com/article/10.1007%2FBF01961568

“Comparison of risk from pyroclastic density current hazards to critical infrastructure in Mammoth Lakes, California, USA, from a new Inyo craters rhyolite dike eruption versus a dacitic dome eruption on Mammoth Mountain” Kaye et al (2009)

http://link.springer.com/article/10.1007%2Fs11069-009-9465-1?LI=true#page-1

“Elastic source model of the North Mono eruption (1325–1368 A.D.) based on shoreline deformation” Shaffer (2010)

http://lycaste.geology.buffalo.edu/monoinyo/downloads/publications/ShBuRe10.pdf

“THE GEOCHEMISTRY OF THE INYO VOLCANIC CHAIN: MULTIPLE MAGMA SYSTEMS IN THE LONG VALLEY REGION, EASTERN CALIFORNIA” Daniel E. Sampson and Kenneth L. Cameron (1987)

http://onlinelibrary.wiley.com/doi/10.1029/JB092iB10p10403/abstract

Copied from comments for completeness, Schteve.

…………..

 

Sheepy Dalek:

Alan C Evil Riddel:

Ladies beware! If you have badly fitting undies, you may find me!!

What am I?
What are my origins?
2 points
I hope you ladies aren’t offended by this one 

Riddle – Name Those Volcanoes 
7 Dings 7 points

Variety number 9280, No 1 is used to produce a splendid accompaniment to VC riddle solving!

French FIS WC silver medalist might have crashed on No 2 whilst he learnt to snowboard-cross

No 3 The ‘toy’ volcano (photo below)

16762 No 4 is potentially hazardous and unstable

No 5’s new island emerged, bravely flew the Portuguese flag & vanished just 20 days later

No 6 (photo below)

With a No 7 Bang Bang I wish us all a belated, but very happy & peaceful New Year!

Spica

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:

Sleeper Fish… A look at the Taal and Laguna de Bay setting.

Palawan Continental Terrane. “Palawan?” According to Google Translate, it means “Sleeper Fish.”

Sleeper gobies are members of the Eleotridae fish family, found predominantly in the tropical Indo-Pacific. There are approximately 35 genera and 150 species.

Interesting… sort of. The Palawan Continental Terrane is actually a fairly sizable chunk of material that has perplexed a few researchers as to where it came from, or how it originated. Before I yammer about that, let me point out what that word actually means… not Palawan, but “Terrane.”

A Terrane is a geologic term for a somewhat contigious block(s) of material that operate/move over geologic timescales as one unit. The boundaries are not really clear enough to call it a crust block or microplate, or microcontinent… though each of those could eventually wind up being a terrane once they get to a resting place, or are plastered onto a continent. Essentially, the material in the Terrane is related to all the other material in origin, chemical make up, and destination. Usually a Terrane originates from one crust block/plate and winds up attached to or sutured onto another. The Wrangellia Terrane is where I learned the term… that’s the region plastered to the North American craton east of where the recent Queen Charlotte quakes occurred at. If you think of bugs and windshields, you get the general idea of how terranes work and accumulate.

From the name “Palawan Continental Terrane” you would assume that it originated from some continent somewhere. According to Knittel et al., it’s a piece of the rifted margin of SE China. So where is it now? Well, it makes up a significant chunk of Mindoro in the Philippines. Mindoro is a collection of three uniquely different chunks of material. The other parts are the Philippine Mobile Belt that the Palawan Continental Terrane is sutured to, as well as a third unit that is made up of metamorphic material and a section that might indicate an ophiolitic unit… complete with gabbros. From Wikipedia: “a section of the Earth’s oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crust”

Okay… so it’s a slow motion collision in process. More correctly, part of a slow motion collision in process. Why part? Well, this affects Taal and Laguna de Bay.

Mukasa et al. points out that other researchers have pinned their origin as products of the subducting plate at the Manila trench, and then further notes that the geochemistry of them has changed as they have grown older. Specifically, they differ from the other volcanoes in the northern part of that chain. (East Bataan Lineament). The reason for this, according to the authors, is the incorporation of Palawan Continental Terrane material into the magma production.

This could explain how Taal and Laguna de Bay could have become capable of making large calderas. By its nature, continental material is more silica rich than oceanic crust. The general thought is that leading shards of this material are intruding into and being caught up in the melt formation process.

As cbus20122 notes:

…It’s amazing that such a large eruption [Pinatubo] only produced a comparative blip of a caldera when looking at the other volcanic areas on the map…

Pinatubo, being on the West Bataan Lineament, is more north and further away from this source of silica rich magma.

Right next to the Taal/Laguna de Bay region is the Macolod Corridor. From the abstract of a pay to play paper by Förster et al (1990):

an approximately 40 km wide zone of still active intense Quarternary volcanism which perpendicularly crosses the Island in a NE-SW direction … we believe that the corridor is a pull-apart zone formed by a diffuse system of NW-SE oriented shearing.

And of course… a plot of sorts. Not my usual, I wanted to focus on quake depths in relation to the major players. This was put together with DivaGIS. Red Quakes are greater than 90 km deep, Blue quakes are less than 90 km deep. Somewhere around 125 km is where melt percolates off of the subducting slab. The majority of the deep spike is under and just to the southwest of the Taal parent caldera. (The one the island of Taal sits in). There are a few deep quakes up around Pinatubo, but nothing like the area around Taal. These are quakes from the USGS list back to 1975 and greater than magnitude 4.5 or so.

GEOLURKING

An after the fact addition: If you note my first graphic, there is a region that forms a “T” with the Manilla Trench that I called “Old South China Sea Spreading Center.” A closer look at this was done in “Basement structures from satellite-derived gravity field: South China Sea ridge” by Braitenberg et al (2005). You may find it of interest. It is what put the Palawan Continental Terrane where it is.

“The Macolod Corridor: A rift crossing the Philippine island arc” Förster et al (1990).

“The Nd-, Sr- and Pb-isotopic character of lavas from Taal, Laguna de Bay and Arayat volcanoes, southwestern Luzon, Philippines: implications for arc magma petrogenesis” Mukasa et al (1993)

“Permian arc magmatism in Mindoro, the Philippines: An early Indosinian event in the Palawan Continental Terrane” Knittel et al (2009)

—————————————————————
UPDATE:
NAME THAT VOLCANO RIDDLE by Suzie!

The prime minister and the volcanologist were having a heated debate about health and safety issues.

”You are grossly over estimating the danger” shouted AP in frustration.
”Yes its active but it has not erupted for a few thousand years, and the local fishing community, who admittedly get a bit confused about their birthdays, stay safe by holding hands!”

”Ahhhh but you are forgetting something important” retorted BP immediately ”smoking kills!”
—————————————————————-
ALAN`S EVIL RIDDLE
Years ago Friday, Her Serene Highness may have worn this green coat under the stars!

1) What am I?
2) My composition and uses?
3) Which constellation could be related to a cousin?
———————————————————
Suzie will do her own Dinging and i will do it for Alan.
Happy riddling Spica

The Dead Zone

Updated 13 Sep 2012, see end of article.

In logic, an assumption is a proposition that is taken for granted, as if it were true based upon presupposition without preponderance of the facts. (Wikipedia)

Back around May of this year, Carl asked me to do a series of simulations using KWare’s Heat3D, a program written by Ken Woheltz and the Reagents of the University of California under the sponsorship of the US Governement. It’s a cool little program that allows you to run heat simulations of magma intrusions into rock of varying characteristics. I had been prompted to write an article about one of the more perplexing areas in Iceland (well, to me it is). Not feeling that I was up to the task, I offered to do the supporting graphics if Carl could find someone to write the meat and potatoes of the article. I killed off a weekend working up the plots, but two of the catch points that we ran into were; “What temperature of the intruding magma should we use?” and “What exactly is the geothermal gradient of the region?”

With those two uncertainties, and the bedlam of real life, the post never made it to the forum. Things happen.

Before I go on, I must warn each and every reader here that I am not a seismologist, geologist, or bona-fide expert in the field. I read a lot, have been “studying” geology and physics in some shape form or fashion for about 37 years. I am just an amateur like many of you, so there is ample room for error.

With that out of the way… now we discuss

First, “The Dead Zone” is not an actual named place. It’s just a colloquialism specific to VolcanoCafe. It’s that region of Iceland between Katla/Torfajökull and Bárðarbunga/Grímsvötn. I refer to it as “The Dead Zone” due to the seeming low number of quakes. Historically, and pre-historically, the region is quite active with fissure eruptions. Irpsit and others can give you more definitive dates and names about the area, but I am limited to what I can cobble together from various sources. There are many other features here, but the main ones that I can find data on are Veidivötn, Vatnaoldur, Skaftar, Eldgja and Trollagigar. (spelling as listed in GVP and may be missing some of the diacritical marks) Veidivötn, Vatnaoldur, and Trollagigar are part of the Bárðarbunga system, Eldgja belongs to Katla, and Skaftar belongs to Grímsvötn. (As parts of the parent volcanoes fissure swarms). As you can see from the overview plot, there just are not very many quakes in this region. (Ignore the dot dashed blue line, that was part of the original plot set and is not used here)

Now, why is the Dead Zone dead? Because it is really… really hot. Much more than you would think. When an eruption is completed, magma sits and cools after the eruption is over with. This cooling rate depends on the thermal conductivity of the surrounding rock. For Basalt, the heat capacity is 840 J/kg K. (this is what I used in the simulations), Granite, for comparison is 790 J/kg K. This is in part due to its lower density. How it works… in order to raise the temperature of one kilogram of the material by one Kelvin (same as one degree C), you need 840 Joules of energy (for Basalt). Since we are talking about heat capacity, Water is 4185.5 J/kg K and Ice (at 0°C) is 2090 J/kg , so you can see how water or ice can drastically affect what is going on. This is one of those “gotchas” that can throw this whole scenario off. This area has a high water table and that can seriously affect how accurate the simulations are. Keep that in mind as I continue.

Anyway… when a dike intrudes into rock, whether it erupts or not, it starts loosing heat at a rate that can be calculated (provided you have the skill, or a program written by someone with the skill). Heat3D runs through the iterations of how heat migrates into the surrounding rock.
Here is how a single intrusion works out over a few years.

In my original set of graphics, I used a temperature of 1600°C magma due to the runniness of the flows and how far they traveled. My original guess was 1100°C based on a statement that I had seen in a paper, and much discussion occurred between Carl and myself about what would be the sane value to use.

“Time constraints on the origin of large volume basalts derived from O-isotope and trace element mineral zoning and U-series disequilibria in the Laki and Grímsvötn volcanic system” Binderman et al (2006) places the temp in the 1120–1140 °C range based on a “Mg in glass” geothermometer. (calculating diffusion and formation rates vs temp and pressure). Another reference (that I can’t locate at this moment) implies a temperature of 1200°C at 250MPa for one of the clast minerals. 250 MPa is in the 10 km depth range. Still uncertain of what temp to use, I went with the program default of 1250°C.

I used a 10 meter dike width based off of the average of three known dike sizes contained in “Geodetic GPS measurements in south Iceland: Strain accumulation and partitioning in a propagating ridge system” LaFemina et al (2005). This produces a really crappy 95% confidence range of 0.5 to 10.2 meters. (three samples is horrendous, but it’s all I had) Since the size of the plot grid has a direct play in how long the simulations take to run, I used 10 meters in order to get the simulations done in one evening.

Okay… now the actual run. As noted, this is not the original, and for brevity, I focused on only one system, Veidivötn. In case you didn’t know it, Veidivötn is probably the most lively fissure system in the region. It’s responsible for many of the Tungnaárhraun tephra layers. (THc. THd, THe…) GVP places an event there at the following dates: -6650, -4800, -4600, -4550, -4400, -4200, -1200, 150. For each eruption, I placed a 10 meter wide dike and ran the program out until the next intrusion date, which was then added and the process repeated. Another “gotcha” that you should be aware of, the eruptions did not necessarily occur in the same part of the fissure. This simulation assumes that they did. In effect, this skews the region towards being hotter than it might really be (and don’t forget the possible effect of the water that I mentioned previously)
So… here is the final product for what conditions may be like under the Veidivötn fissure. The temperature scale from the previous plot applies here.

Pretty gnarly eh? This is the crux of why I think that you won’t really see many small quakes in this region. Each one of those fissure lines has a heat structure similar to this. The crust is for the most part, plastic and yields to any stress that comes along… until it arrives too quickly for it to give. Then you have the larger quakes and potentially an opening of the fissure if the conditions are right… such as a nearby parent volcano being at or near erupting and having a ready supply of magma to flow down the rift and open it the rest of the way up. Structurally, there isn’t really much there to hold the two sides together. Plate shifts can do it (tectonic), or a parent volcano.

From “IAVCEI General Assembly 2008 Conference Field Excursions, Excursion 1: Historical Flood Lava Eruptions The 1783-84 Laki and 934-40 Eldgjá events” August 14-17 2008

“In 1783 the people of south Iceland had enjoyed a favourable spring and were looking forward to summer. However, their destiny was about to change. Weak earthquakes in the Skaftártunga district in mid-May were the first sign of what was to come. The intensity of these earthquakes increased steadily and on 1 June they were strong enough to be felt across the region from Mýrdalur and Öræfi. The earthquake activity escalated up until 8 June when a dark volcanic cloud spread over the district, blanketing the ground with ash (Figure 18a). The Great Laki eruption had begun.”

I’ve worked out the distances to Mýrdalur and Öræfi from the Laki site and applied an Mw to MMI estimate based on a few real world quakes from the USGS catalog in order to get a feel for how the power drops off over distance. Based on the MMI levels at which a quake becomes detectable by an unaided person, the quakes leading into the Laki event were in the Mag 4.5 to 5.0 range.

It’s a bit of a reach, but extending the formulas from “New Empirical Relationships among Magnitude, Rupture Length, Rupture Width, Rupture Area, and Surface Displacement” Wells and Coppersmith (1994) down to Mag 4.5, you get the following numbers.

Mag 4.5 – Surface rupture length 0.5 km, Subsurface rupture length – 1.3 km, Downdip rupture width – 1.7km.
Mag 5.0 – Surface rupture length 1.3 km, Subsurface rupture length – 2.7 km, Downdip rupture width – 2.9 km.

THESE ARE ESTIMATES

There is a bit of slop in the formulas, it is an attempt to get a working estimate of the physical manifestations that you would see from a quake. These particular formulas are only considered reliable for events down to Mag 5.2, but they do track well with no oddities in the curves. Below 5.2 the confidence in what the formula says drops off.

From that, it seems that the Mag 4.5 to 5.0 quakes are what is needed to open the system up. They have the right sort of features; the crust itself has likely healed very little from the previous events and should not take a lot of energy to re-open.

All this rumination and reading is one thing… but there is always something missing when you think and talk about these fissure eruptions. That’s the scale of the things. Since none of us were around, we just don’t know or have a frame of reference. All we have are eyewitness accounts. From some of those accounts, we know how long or how tall the fire curtain was, but that’s it. Just numbers in a book. Here, I have scaled an image of a generic fissure eruption and placed a few well known silhouettes in front of it so that you can see just how big these things are.

Enjoy.

GEOLURKING

GL Edit: The silhouetted buildings are;
Empire State Building – 443.2 m, Taipei 101 – 449.2 m, Burj Khalifa – 829.84 m, Sears Tower – 527 m, Petronas Towers – 451.9 m

“GVP” = Smithsonian Institution – Global Volcanism Program

UPDATE:

Irpsit says:
September 12, 2012 at 18:26

From what I know Laki eruption could be observed from almost anywhere in Iceland, in distance. The reports even speak that you could see the fountains from far away, but probably not everywhere in Iceland, as 1km high is not enough for that.

This put me on a search for two of the images that I made for the original article. I was able to pull them from Google archive of my mail.

They are not as stunning as the scaled image, but they are worth pondering. The ruddy maroon rectangle represents the Skaftar (Laki) fire curtain anchored to the surface, as seen from a couple of locations.

Name that Lava XXI and Alans riddle #14 + Katla update

Katla

First of all before we go weekend nuts with volcano riddles I would like to point out that the largest earthquake in Katla, one of the most talked about volcanoes on the planet, during the last 13 years was when the glacier snapped apart due to summer melt. This is truly a bad year for the 2012ers. The earthquake measured 3.8M and was at 0.1km depth.

Name that Lava

Today there are 4 points to earn:

1. The correct rock-type, granite not good enough
2. The main mineralogy og the rock
3. The 2 accessory minerals – brassy and grey
4. What climbers delicacy is the area known for

Second image for the Name that lava competition. Both pictures are of the same lava.

The standings in the Name that Lava competition:

10 Spica
7 DFMorvan
6 Sissel
5 Ursula
5 Diana Barnes
4 Talla
4 KarenZ
3Lughduniense
3 Cryphia
2 Doug Merson
2 Hattie
2 Schteve42
2 Irpsit
2 Stephanie Alice Halford
2 Lisa
1 Jim
1 Luisport
1 Inge B
1 Heather B
1 Jamie
1 Henri le Revenant
1 UKViggen
1 Alan C
1 Bobbi

Evil Alan’s Riddle!

‘If you wish to see my castellated layers, look hard amongst empty shells!
Oh! and don’t forget to look; you may find a dyke!’

a) What exactly am I?
b) With what is my dyke associated?

Rock-on folk!!

And the standing in the Evil Alan’s Riddles are:

6 Talla
5 Sissel
3 Henri le Revenant
3 KarenZ
2 Ursula
2 Chryphia
1 purohueso745
1 UKViggen
1 lughduniese
1 Carl
1 Spica

Good luck to everyone!

Good news about Grimmster

December 2011: Exciting blog times: Bobs activity was intensively monitored, while Carl fullfilled his famous Russian grenades tank expedition.

Fellow commenter Grimmster was leaving for El Hierro to explore the island and take pictures of everything of interest for a couple of weeks. Many of us would have been very happy to join him.

In January we started to ask ourselves where he was. But months passed by without anymessage.

At last I sent Grimmster an email, concerned as I was, hoping that he would respond. And then another one. And guess what -  today I got a mail! His daughter Karen explained what had happened and brought a heart warming message:

“This is to let you know that my Father had a really bad accident on the way to the Airport when on his trip to the island, he is still in hospital but should be home in a couple of weeks.

I visited him today and he is greatly looking forward to reading all ofthe Posts on your Blog, he has really missed you all.

He was in a Coma for quite a period but is expected to make a full recovery, its taken so long to reply to you as reading his emails was the last thing on his mind at the time.

Kind Regards to you all, and he asks that you pass this on to all the bloggers he calls Friends”.

We can write our answers to him here, I’m sure it will not take long untilhe can read it all!

- Thanks to daughter Karen who let us know.

ALAN, CARL & SISSEL