Fukushima quake

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There was a quake near the coastline of Fukushima today. USGS had it as a 5,9. GFZ as a Mag. 6 quake. http://geofon.gfz-potsdam.de/eqinfo/event.php?id=gfz2013jqtk

When seeing that this morning it reminded of the times when i watched the news about Fukushima on TV. This happened in the direct aftermath of the devastating Tōhoku quake and Tsunami which struck Japan on March 11, 2011. (http://en.wikipedia.org/wiki/2011_Tōhoku_earthquake_and_tsunami) I am certain many here remember the terrible videos and images.
I asked on VC if such a quake as today would have harmed the nuclear powerplants near the coastline if the incidents 2 years ago had not already happened and Carl ensured me, the plants were built to withstand such an earthquake unharmed. What was the problem was, that the Tsunami was more than twice as high as the Fukushima plants could handle.

I remembered hearing of problems with a second atomic power plant back then, Fukushima II also called Fukushima Daini. Then there was a message in the news on local tv, that the situation was dealt with and nothing happened suggesting there was no further threat of a possible melt down or contaminated water escaping.

I had forgoten about the second power plant story till today. What happened in Fukushima I was too severe to be covered up and is now a topic in the media rather often. I just recently watched a documentation about a study on mutated butterflies in the region around Fukushima.
But what about Fukushima Daini? http://en.wikipedia.org/wiki/Fukushima_II_Nuclear_Power_Plant

I read it had a cold shutdown.  So i asked you people here on VC

Spica: May 18, 2013 at 08:59

The Wikipedia ariticle says, that Tepco wanted to release the remaining 7000 tons of seawater back into the sea in July 2011 since the reservoirs holding it back started corroding but did not get permission to do so. Now it is more than 2 years later… what happened to the water till 2011?

Sa’ke: May 18, 2013 at 10:30

What I heard, but don’t know the sources anymore: They have to keep water running over the reactors to cool them down. The trouble is the cooling water becomes radioactive due to close contact with the reactor. Sometimes they have to change the water because it becomes that much radioactive the pipes/watertanks start to corrode. I believe in April this year they had a leakage and a lot of radioactive water leaked in the ground and pacific sea. I believe they have huge storrage problems for the water. They still want to dump loads of water in the oceans.

This is a press release from 14 may 2013:http://www.japantoday.com/category/national/view/tepco-seeks-permission-to-dump-groundwater-from-fukushima-plant-into-ocean?utm_campaign=jt_newsletter&utm_medium=email&utm_source=jt_newsletter_2013-05-14_AM

Carl: May 18, 2013 at 10:07

Without checking the specifics regarding the water.

But, the powerplants are well able to take a 6M earthquake, the japanese ones are also actually secondarilly strengthened against earthquakes above any other powerplants on earth.
Problem was that they where not built for the 9.4M earthquake that hit Fukushima. Nothing in the end is built to take that. Problem is that the japanese plants should all have been on the other coastline for safety reasons.
In the end a nuclear powerplant should not be built in an area like that where you have had numerous historical ultralarge earthquakes. And… One should not build them at all since they do time and again release crap. Even when there is no accident the mining is poisonous enough. Blekh!

Does anyone have more informations on Fukushima Daini and the contaminated water? Was it released into the ocean? Did it just leak out?

Nothing much is going on with volcanoes as far as i could grab today, so in agreement with Carl, i thought to make a small post of my worries. After all, even though Japan is really far away from Europe. In case the radioactive water is in the Pacific Ocean it will have an effect. Not only the local fishermen might be affected. Fish is shipped and traded all over the world. And who knows which other species might be harmed , or where the ocean currents will carry the radioactive water.

Spica

The Usual Suspects and Friday’s NtV Riddle

Photograph by Eggert Norddahl under exclusive right to Volcano Café. Hekla 1980 eruption.

We are minutely studying any hiccup from the Icelandic Usual Suspects. In the case of earthquakes we are quite used in getting all sorts of useful stuff out of them. One of my favorite ways of studying earthquakes in volcanoes is the cumulative seismic release (CSR). In the case of Grimsvötn it might even be the perfect way of predicting how close he is to erupting. Except for Hekla the Icelandic volcanoes are rather noisy, but how noisy is a volcano in the making?

I had this question ringing in my head yesterday so I tallied up the sums for Iceland’s only known proto-volcano, the Gódabunga cryptodome. A cryptodome is a magmatic emplacement that is unerupted; it is a magmatic system in the making. Normally it suffers several magmatic emplacements before erupting, but most often a cryptodome never erupts. The reason for them not erupting is that it takes a tremendous amount of energy and pressure for a volcanic opening to form. These virgin territory emplacements are hideously noisy compared to a regular volcano.

I had handy data for Eyjafjallajökull, Gódabunga, Grimsvötn, Hekla, Katla and Torfajökull. I discarded Hekla since it would not even show as a speed bump compared to the others. In the end the results got interesting.

The data is from July 1991 up to February 2013 except for Grimsvötn (1996). Energy is in Joules, as a comparison one could use a Big Mac; at 540 kilocalories it has 2.2 million Joules of energy (roughly equivalent to a 1.1M earthquake).

Eyjafjallajökull

Photograph by Eggert Norddahl under exclusive agreement to Volcano Café. Eyjafjallajökull eruption 2010.

Eyjafjallajökull was rather active before the eruption in 2010, the total CSR was 6.8e+9 and otherwise Eyjafjallajökull was rather quiet during the period. The total tally including the VEI-4 eruption during the period was 1.06e+10. As you will notice this is surprisingly little. Let us now walk over to the quiet neighbor to the north. After the eruption this volcano has been very quiet.

Torfajökull

Torfajökull, the forgotten and quietly playing volcano.

This volcano latest erupted in 1477 and has since then not erupted, but it is still active. It suffers from two opposite forms of earthquakes. It simultaneously has earthquakes associated with cooling magma, and earthquakes associated with magmatic emplacement. It is probably safe to assume that this large volcano has more than one chamber, and that the most likely spot for an eruption will not be at the same place as the last one.

It would therefore have been interesting to have these earthquakes separated, so we could compare. But alas, we do not have that. The total sum during the same time period is 4.8e+9. Except for 2010 Torfajökull had higher CSR then Eyjafjallajökull during the entire period.

Grimsvötn

Photograph by Eggert Norddahl under exclusive agreement to Volcano Café. Grimsvötn 2011 eruption, sun over ash cloud.

For being a very large volcano Grimsvötn is surprisingly quiet. The earthquakes during the period from 1996 are rather even over the years, with the only exception being
the period after the 2011 eruption where the volcano has been very quiet.

Grimsvötn seems to erupt as soon as it has reached a certain value of CSR. At least it did that the last two times in 2004 and 2011. That value is slightly more than 3.8e+9. The total strain release between 1996 and now is 7.7+9e, or slightly more than Eyjafjalla released in the 3 months before erupting up to the end of the eruption. Who thought Grimsvötn would be the shy quiet one?

Katla

I guess nobody will be surprised that Katla is a noisy volcano. It suffers from numerous small to medium sized earthquake swarms. Many of those are signs of magma entering the system. The noisiest year was 2011-2012 when the volcano suffered from a CSR of 8.9e+9. During the entire time the CSR was 3.1e+10. Now, let us go and visit the noisy unborn baby volcano next door.

Gódabunga

Gódabunga Núnatak next to the SIL station.

Gódabunga was a quiet unassuming little Núnatak (cliff protruding above a glacier) just on the outside of the caldera wall of the massive Katla volcano when, to the surprise of everyone, it started kicking around. In 96-97 it had a CSR of 1.8e+9 and most thought it was Katla having a side emplacement. The next year it got a CSR of 6.5e+9 and it was noticed that the hypocenter of the earthquake ball was outside the Katla system. It caused a bit of a stir; remember that all of a sudden out of the blue there was more CSR than Grimsvötn produces during the entire run up to an eruption.

For two years it was showing signs of calming down after the initial emplacement. Gódabunga seemed destined to dwindle into the mist of magmatic emplacement history, the same way 99 percent of all emplacements go.

After the two years Gódabunga went on a massive spree of large emplacements that really knocked on the roof of the teenage room.  During the next five years it had at least two more even larger emplacements than the initial one. The CSR for the period was 6.03e+10 with the record year (2002-2003) blasting an impressive CSR of 1.83e+10.

After those five years Gódabunga has calmed down, but the CSR is still 100 times higher than before the commotion started. The total release during the period is a whopping 9.02e+10.

What will happen to Gódabunga is written in the stars so far. Remember that science have never seen a large new volcano blast into life, especially never with instrumentation like this. The ones science has seen have been rather small, and they have been un-instrumented. If Gódabunga ever is born we only know one thing, it will be very noisy.

Ruminations

For those who are surprised over how quiet Grimsvötn is should remember that this volcano is erupting often. The system is permanently heated and filled with magma, so the roof over the chambers cannot withstand a lot of pressure. One should also note that the earthquakes in a volcanic system are a sign of pressure increase (or in some cases of pressure decrease as magma cools down and contracts). So, Grimsvötn will show comparatively few earthquakes before erupting since it cannot take a lot of pounding.

The fact that Grimsvötn has a weak top is what makes CSR into a good predictive tool. The amount of pressure increase the roof can take will be about the same between the eruptions. At least for as long as the eruptive cycles have roughly the same time spans.

As the roofs above volcanoes cool down it will take more and more pressure for a volcano to break through. Also size and depth of the magma chambers are factors that affect the amount of pressure needed for an eruption to occur.

Eyjafjallajökull had a rather small magmatic system that was fairly close to the surface (after an emplacement just before the period my data covers), so it had a surprisingly small conflagration of earthquakes before erupting.

Katla has not erupted since 1918, and has a very large magma system. So the roof has had time to solidify and can due to the size flex quite a lot over time. So, it is not that surprising that it can withstand a lot of CSR over time.

Gódabunga on the other hand has an unknown size of the magmatic system, but one thing is clear, it is fairly deep down, and the roof is (no pun) rock hard. Here the magma has to quite literally pound its way through layer after layer of hard old rock so naturally there is a lot of music being played. How much more pressure will it take before an eruption occurs? The answer is that nobody knows. All we can do is waiting for a new emplacement and then try to track the progress of the earthquake ball hypocenter upwards. For all we know it could withstand anywhere up to ten times as much CSR, especially if it is temporally well spaced.

Numbers taken from Icelandic Met Office and treated by Carl, then made into a plot by GeoLurking.

If the CSR is a representation of the systemic pressure inside an unborn volcano, the Gódabunga is potentially a bad one. If we compare with El Hierro that had an eruption after a long repose time and had a very noisy eruption the energy released there was still 1 000 times less. In the end we are faced with the small thing that the CSR are caused by a magma emplacement, and the amount of activity gives a hint of the amount of magma emplaced.

CARL

Name those Volcanoes Riddle

 1 point for each Volcano …

No 1 - Legendary lost home of the hairy eared dwarves? SOLVED Mount Shasta 1 point Sa’ke

http://en.wikipedia.org/wiki/Mount_Shasta

http://en.wikipedia.org/wiki/List_of_lemur_species

No 2 - 4295 eponymous deposit. SOLVED Katla / Vedde Ash 

http://en.wikipedia.org/wiki/Katla_volcano

http://en.wikipedia.org/wiki/Vedde

No 3 - Thoroughly well bred parent of the US Ambassador? SOLVED Acatenango 1 point KarenZ

http://www.sportinglife.com/racing/profiles/sire/98444/acatenango/progeny

http://en.wikipedia.org/wiki/Acatenango_(horse)

http://en.wikipedia.org/wiki/Acatenango

No 4 - Slightly under 50 miles north of a pillar of salt. SOLVED Aukland volcanic field 1 point KarenZ

http://en.wikipedia.org/wiki/Auckland_volcanic_field

No 5 - Its location and summit hold a global distance record.  SOLVED Chimborazo 1 point Sa’ke

http://en.wikipedia.org/wiki/Chimborazo_(volcano)

No 6 - Site of the earth’s nastiest outside loo. SOLVED Mount Elbrus 1 point Alison

http://en.wikipedia.org/wiki/Elbrus

KILGHARRAH

How to read the Icelandic borehole strain and seismicity plots and NtV Riddle

In this post I will elaborate on how to understand the Icelandic borehole strain and seismicity graphs. For the experts I might just be stating the obvious, but for the more general public (like myself) this might be a guide on how to understand all these enigmatic waves and ripples.

This map shows the locations of three kinds of instrument that monitor earthquake and volcanic activity around Hekla volcano. SIL stations (of the South Iceland Lowland automatic earthquake data acquisition and evaluation system; black triangles), GPS stations (yellow) and volumetric borehole strainmeters (green squares).

Location of the SIL and GPS stations and borehole strainmeters.
Image courtesy of IMO
http://hraun.vedur.is/ja/hekla/Stadsetning_stodva_31052011.jpg

Strainmeters can be of various design. In Iceland we are dealing with Sacks-Everton volumetric strainmeters. Wikipedia reveals: “a design that uses specially shaped volumes to measure the strain tensor.” In other words, changes to the volume of a fluid filled chamber anchored in the borehole.

Image courtesy of IMO
http://hraun.vedur.is/ja/hekla/thensla_burfell.html

The sample rate of the volumetric strainmeter data is one second (1 sps = samples per second, i.e. 1 Hz). The unit “strain counts” on the vertical axis is arbitrary, because a gain is manually set to determine what amount of relative change in strain or stress is one count. Strainmeters indicate ground velocity (displacement per time). Positive strain values mean volume increase in the bedrock (extension due to tension force, i.e. strain), negative values decrease of volume (contraction due to compressive force, i.e. stress). If you think of driving a vehicle, this plot shows your velocity relative to the starting velocity, since the start of the trace is always set to zero. A massive drop or rise might for example indicate you came to full stop at a tree or reached escape velocity for space travel.

Whether a strainmeter shows extension or contraction during an eruption depends on its relative position to the conduit/rift, see the opposite reactions during the Hekla 2000 eruption.

Búrfell darkblue,
Saurbær blue, Skálholt red, Geldingaá yellow, Stórólfhvoll violet, Hella light blue. Image courtesy of IMO
http://hraun.vedur.is/ja/englishweb/heklafigure1.html

Besides the Hekla strainmeter Búrfell is the second closest to Hekla, roughly 15 km at a perpendicular angle to the rift direction. The huge strain drop (i.e. massive stress increase) at Búrfell was interpreted as magma forcing it’s way up, opening a conduit. On the other hand, the simultaneous strain increase (decreased stress) at the other stations was due to emptying of the magma chamber. Here is further (paywalled) read on the strain during the 1991 Hekla eruption. The unit nanostrain indicates a change by a billionth part of the volume, i.e. 10^-9. Earthtides are known to have an amplitude of about 50 nanostrains. The 2000 eruption caused a sudden drop about an order of magnitude larger.

A seismometer literally measures shaking, i.e. motion of the ground, which can be recorded as a seismogram.
The seismometers of the SIL array can both measure ground displacement (unit is meters per second, m s^-1) or be used as accelerometers (unit meters per square second, m s^-2).
Most Icelandic seismometers are 5 sec (0.2 Hz resonant frequency, limiting the frequency range) Lennarz seismometers. The sampling frequency is 100 Hz. The Haukadalur seismometer (63°58´08.4´´ N / 19°57´54.0´´ W, appr. 10 km West of Hekla) is a LE-3D/5s, measures oscillations in three dimensions (“transverse”, North-South; “radial”, East-West; “vertical”, Up-Down).

Tremor amplitude time series with different frequency bands. Vertical axis: One-minute averages of the vertical component of the tremor amplitude, x micro meters s^-1. Image courtesy of IMO
http://hraun.vedur.is/ja/hekla/oroi_hau.html

First of all, this graph does not show the raw seismogram, but is a spectral analysis. You remember the colorful spectrograms from the El Hierro stations? A spectral analysis is performed on the waves of the seismogram to extract oscillations of different frequencies. Several algorithms can be used to create a spectrogram, for example STFT, short-time Fourier transformation, or CWT, continuous wavelet transform. For El Hierro the amplitudes are given over the whole frequency range while in Iceland they show averages of three frequency bands.

This example is a tremor amplitude time series showing averages of the frequency bands 0.5–1.0 Hz (red line), 1.0–2.0 Hz (green line) and 2.0–4.0 Hz (blue line), of the vertical component (Z) for the station HAU. Unfortunately the vertical axis is not labelled, but is presumably representing the amount of bedrock displacement in micro meters per second multiplied by a variable scaling factor (x). The values are presumably one-minute averages. An example for this analysis is described e.g. in this thesis, see p. 564 ff.

The blue trace (high frequency band, fast shaking) mainly represents earthquakes and the green and red traces (low frequency bands, slow shaking, harmonic tremor) tremor from magma movement, which for Hekla is usually in a well-defined spectral band at 0.5–1.5 Hz (see the thesis).
Based on previous observations, the  following scenario might occur when the next eruption is about to happen: First there will be more earthquakes opening a fissure, showing as an increase of the blue earthquake trace amplitude by an order of magnitude. When the fissure is opened earthquake activity seizes and the blue trace will go back to normal. Meanwhile the magma starts spilling out and a sudden increase in the red and green tremor trace amplitude by at least an order or magnitude will be seen, which gradually decays with decreasing pressure. What we should actually look for in this graph is not the width of the traces, which only indicates how much the shaking amplitudes vary, but a really really strong rise of the curves as seen in 2000:

Tremor amplitude time series with different frequency bands. Vertical axis:  One-minute averages of the vertical component of the tremor amplitude, x micro meters s^-1. Image courtesy of IMO
http://hraun.vedur.is/ja/hekla/hau20000226.gif

Lastly, the following graph is a composite of data derived from the volumetric borehole strainmeters and from the Haukadalur seismometer, plus information on local earthquakes determined by the SIL system.

Upper panel: Volumetric strain rate.
Lower panel: earthquake magnitude (left), horizontal components of tremor amplitudes (right)
Image courtesy of http://hraun.vedur.is/ja/hekla/borholu_thensla.html

The upper part shows the “two-minute median from one-second data” of borehole strain rate (strain counts per second) measured by the four stations Búrfell, Hekla, Hella and Stórólfhvoll. See the green squares on the map. A change of the strain rate means the bedrock is compressed or extended faster or slower than before. The cause of this is a change in the pushing or pulling forces. Think of it as your vehicle being accelerated or decelerated when pushing your gas or brake pedal. This graph shows what your feet do. When Hekla erupted in 2000 the strain rate looked like this:

The rate of strain changes in Búrfell (blue, 15 km from Hekla) and Skálholt (red, 45 km from Hekla) (nanostrain per hour)
Image courtesy of IMO http://hraun.vedur.is/ja/englishweb/heklafigure3.html

The minimum in the strain rate indicates the time of the surface breakout of the magma, along with the visual observation of the eruption at 18:17.

Because the ground is moved by several variable sources, mainly earth tides (very slow change in strain counts rate) and microseismicity (very fast change in strain counts rate) the above mentioned two-minute time range is chosen by which these events are filtered out. Then the median, the mean value separating the higher half of a data sample from the lower half, is plotted.

The left axis in the lower part shows the magnitude (in Ml) of local earthquakes. Since most of the time there are no earthquakes (counted in the lower right corner) no trace appears.

The right vertical axis in the lower part indicates the bedrock displacement, i.e. velocity in micro meters per second. The data is derived from the horizontal components (North and East) of the Haukadalur tremor amplitude time series data, which are 60-sec averages. Short-lasting shaking, for example caused by single earthquakes or a sledge hammer, are averaged out by plotting the the three-minute median. When an eruption is imminent, the blue (high frequency) trace will rise first indicating fissure opening and the green and red traces will follow when the eruption starts.

Standard VolcanoCafé disclaimer: I am not an expert on this topic, just read a few papers while researching for the post. Please excuse me if I jumped to false conclusions and feel free to post corrections!

chryphia

Many thanks to the dragons who read the draft and special thanks to Geolurking for helpful comments!

Other links:
-The SIL seismological data acquisition system – As operated in Iceland and in Sweden. Abstract only (2003)
-How a seismometer works from Sep 25, 2012 by Geolurking
-Summary about long and short period and broadband seismometers in this blog post
-ON THE USE OF VOLUMETRIC STRAIN METERS TO INFER ADDITIONAL CHARACTERISTICS OF SHORT-PERIOD SEISMIC RADIATION
-Seismometers of the SIL used as accelerometers
- Earthquake engineering research center, University of Iceland operating the Icelandic strong-motion network since 1984.
-Sturkell et al., 2005, Volcano geodesy and magma dynamics in Iceland
-Description by IMO of the Hekla 2000 eruption.
-Visualizing Stress is a good site, even if you are not into the math aspects of it, it has some really good narative data in the tutorials.

Name those Volcanoes Riddle

1 point for each volcano … enjoy!

No 1 - Did it crash in the Gobi Desert during CE3K? SOLVED COTOPAXI

No 2 - Volcanic group associated with siblings and satelites. SOLVED LES PLEIADES

No 3 - In English it can be added to seal, crow and mantis. SOLVED HEKLA

No 4 - Bruce and Nigel’s buddy studies this one. SOLVED Axial Seamount

KILGHARRAH

Shaky week for volcanoes

We now reached midweek and there has not been much new going on in the volcano world, but some earthquakes happened. One of which was really close to a volcano.

Perspective of Mount Oyama Volcano, Miyake-Jima Island, Japan. (ASTER-SRTM)
10 August 2000
http://photojournal.jpl.nasa.gov/catalog/PIA02771
NASA/JPL

Michael Ross informed us that he had a tweet saying something seems to be going on under Miyakejima volcano in Japan? Earthquake swarm in last 3 hours M2.9, 3.2, 4.7, 4.1, 3.0, 3.0, 4.6, 4.4 per JMA

Image Wikimedia Commons: Miyake-jima, 2001-04-01

Diana and others immediately started trying to find information on this volcanic island. http://staff.aist.go.jp/a.tomiya/miyakeE.html “A human view of an amazing community living on the edge of a lethal time bomb.. This Island is not a place you would expect to find “happy dancing natives” WRONG!

http://all-that-is-interesting.com/the-town-where-everyone-wears-a-gas-mask Hats off to the Japanese Tourism industry and government bodies who have, like Iceland and other Volcanic areas, utilised the danger, the beauty and the power and turned potential disaster into a lucrative industry for the locals. Authorities of El Hierro take note! Here is the most brilliant piece of advertising copy ever. It turns around the images and real threat of death and destruction and encourages would be holidaymakers that this is the ideal place for a Vacation of all vacations. It looks beautiful…….. Please read all 3 sections……” ( Thanks Diana Barnes)
Miyakejima – Part 1
Miyakejima – Part 2
Miyakejima  - Part 3

There was a 5+ earthquake close to the volcano. GFZ has it as 5.6 
An of course Earth Quake Report covers this event too! GVP on Miyakejima
The volcano itself is called Mt. Oyama: Wikipedia Info

List of recent quakes in the area.

Another quake just happened. GFZ has it is 5.7. Others sources place it as 6.2

————————————————————————————————-

Summary made out of comments on VC on yesterdays earthquake in Iran:

http://geofon.gfz-potsdam.de/eqinfo/event.php?id=gfz2013hkrc

http://geofon.gfz-potsdam.de/eqinfo/event.php?id=gfz2013hkrc

Earth Quake Report on the Iran- Pakistan quake.

Daily Mail: http://www.dailymail.co.uk/news/article-2309892/Iran-earthquake-2013-7-8-magnitude-quake-hits-near-Iran-Pakistan-border-hundreds-feared-dead.html

Iran has a rocky, mountainous soil, while the hard hit Pakistan region is built on a dry lake. That may be the reason why there are more victims to mourn in Pakistan.

Earthquake Report is attributing the death toll in Pakistan to building on lake sediment: http://earthquake-report.com/2013/04/16/massive-earthquake-iran-pakistan-border-region-on-april-16-2013/

From BBC news website. “Tuesday’s earthquake was about 180 times stronger in energy release than a 6.3-magnitude quake that struck on 10 April near the nuclear plant at Bushehr in south-western Iran. That quake killed at least 37 people and wounded 850.” http://www.bbc.co.uk/news/world-middle-east-22168202

USGS M7.8 – 83km E of Khash, Iran http://earthquake.usgs.gov/earthquakes/eventpage/usb000g7x7#pager

The shake map has been upgraded to VIII:http://earthquake.usgs.gov/earthquakes/eventpage/usb000g7x7#shakemap

According to John Search, the Iran 7.8 EQ was 100km SE of Taftan Volcano: http://www.volcanolive.com/news.html

http://www.volcano.si.edu/world/volcano.cfm?vnum=0302-05-

————————————————————————————————-
Earth Quake Report on the Papua New Guinea quake.

BBC http://www.bbc.co.uk/news/world-middle-east-22178765 ( thanks Diana Barnes)

KarenZ: ”M6.8 – 19km ESE of Aitape, Papua New Guinea 2013-04-16 22:55:26 UTC 8km http://earthquake.usgs.gov/earthquakes/eventpage/usb000g8my#summary
Can’t find a volcano in its immediate vicinity. The nearest seem to be Doma Peeks, Crater Lake and Blup Blup.
http://www.volcano.si.edu/world/region.cfm?rnum=05“

I think i can add another odd volcano name to my list of favorites: Blup  Blup!
Here is what Volcano Discovery has on it.

And just so this does not get lost! dfm gave some info on seismic signatures http://www.iris.edu/hq/programs/education_and_outreach/animations/17

Spica

El Hierro still going strong and a riddle

Some parts (?) of El Hierro experienced a short power outage last night, This was also viewable on the solitary working webcam at the moment which was noticed by some regulars. Quite some earthquakes Mag. 3+ and even some Mag 4+ have been recorded.

chryphia created a new plot which shows the action going on:

Quote:” Here is another 3D plot, no overlays this time .
It shows the current swarm and the older earthquakes in two separate color scales. I wanted to see where the central El Golfo bay earthquakes are located exactly: they are slap-bang in the middle of the northernmost, deep (magenta) swarm, barely visible in this plot. This is where all the other swarms originated, thus I am worried that there is even more magma arriving now. For a good 2D view look at http://www.01.ign.es/ign/resources/volcanologia/html/eventosHierro.html

“

Earthquake Report has a link to an image of all the spectrograms of this crisis stitched together: http://jdcv.es/Media/Hierro/2013/CHIE_upto2903_B.jpg
from http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/
Noted by Jim Ludwell.

Earthquake-report.com also used chryphias plot without giving her credit which I personally find absolutely not OK.

Many can explain the current crisis much better than I ever could. So here there are some comments to good to be lost:

GeoLurking says: March 29, 2013 at 04:37
Quote: “when this whole thing was first bopping along, the gov was reticent about doing anything until it became clear that Mag 4.0 quakes were a possibility. Mag 4.0 was where they flinched and it was clear that something could shake loose and hurt somebody, so that was about when they started taking precautions.

One thing that Carl noted was that the seismic gear was probably not set up for volcano monitoring and that IGN and Pevloca had to undergo a paradigm shift from watching for potential landslides to watching for volcanic activity. Outside experts were consulted and new gear was brought in. (the temporary seismic stations and the additional GPS units.)

Now 4.0s seem to be regular fare. It doesn’t lessen the hazard. A 4.0 still releases considerably more energy than a 3.0.
For now, the most immediate threat is still the same. Something getting shaken loose from the bluffs.

Then there is how it plays in the volcano scheme of things. If the quakes are being caused by magma forcing it’s way through the rock, the best that I can envision is a series of normal mode faults. A 3.0 has a maximum displacement of 0.275cm. A 4.0 has 1.17cm. That’s would be a crack about 4.3 times the size of the 3.0. Keep in mind that this is probably pushing the Wells-Coppersmith equations a bit outside of what they were intended for, but it does illustrate the differences in the two quake sizes.

If it is magma pushing through rock, what has happened is that the hoop stress of the rock around the area of the magma has been exceeded and the magma breaks open the rock with what is probably a mode 1 crack. This realm of math is beyond me, so I rely on the Wells-Coppersmith crutch to provide some level of understanding. Going whole hog, and looking at the rest of the formula… a normal mode fault of Mag 4.0 has a down dip rupture width of 1.82 km. If intruding magma is what is at play, it could conceivably make a path about half of that width higher each time it happens. If that starts to show up in the quakes…“

Read the whole comment by clicking it.

Renato Rio says: March 29, 2013 at 13:34
Quote: “The PEVOLCA maintains civil protection measures in El Hierro and follows the evolution of the phenomenon
03/29/2013 … 12:38 – Ministry of Economy, Finance and Security
* The data indicate that the seismicity has migrated to the southwest in the last 24 hours. The direction of the Civil Protection Plan for Volcanic Risk (PEVOLCA) maintains civil protection measures that were taken last Wednesday in El Hierro given the magnitude of the seismicity that is occurring to the west of the island.
As you may recall the steps taken by the management of PEVOLCA are the following:
Disabled the lane closest to the on the output side of Frontera tunnel closing the stretch of road between the HI 50 between Cruce de la Tabla and Sabinosa and the access road to the Playa La Madera, the Pozo de la Salud to the confluence with the HI 503. It is important to avoid transit through these areas because of the risk of landslides.
Accesses are opened to the Ermida de los Reyes and the southern Sabinar area, HI 400
Meanwhile it is maintained the yellow alert of information to the population in the area bounded by the HI 500 and the height of the Pozo de la Salud to the south, at the confluence of the HI HI 500 with 400 in the crossroads known as El Tomillar.
As for the seismo-volcanic phenomena, earthquakes located in the last 24 hours have migrated slightly to the southwest over previous days, reaching the west of Orchilla between 15 and 20 kilometers deep at a distance from the coast between 12 and 15 kilometers. The values ​​of CO2 in the atmosphere have increased but are still within normal parameters.
The direction of PEVOLCA wants to remind you that they are doing continuous monitoring and real-time of thr phenomenon, so any change in the pattern of movements that imply risk will be communicated immediately. It also recommends considering the advice of self-protection in the event of earthquakes, known to all, and can be viewed in http://www.gobiernodecanarias.org/dgse/descargas/sismo_hierro/autop_sismo.pdf“

Bruce Stout did some drawings:
To understand the images one needs to read Bruce’s comment and all the follow up’s by Peter Cobbold and Bruce. Bruce Stout says: March 29, 2013 at 14:23

Richie Lee gave us a link to a TV station in the Canary islands where some news might be broadcasted. Canary TV: They don’t stream everything but most live newscasts are available. The last few days they have had coverage of the El Hierro activity.

http://www.rtvc.es/television/enDirecto.aspx?canal=tv

I personally do not think any eruption is imminent, but it is interesting to watch. And in case you need the links again, just holler.

Spica

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A riddle for tonight, while we are watching what is happening in El Hierro and Iceland!
Same as last week …. so link the each clue to a volcano and spot the red herring ….

1 point for each volcano and 1 point for each red herring (with brief explanation)

All solved … Red herrings in bold … Answers ..

No 1 Big Ben

No 2 Mount Churchill

No 3 Hekla

No 4 Glen Coe

No 1 – 2745; Furious 50s; New York landmark; Augustus Pugin; SOLVED
No 2 – Bobsleigh run; Radiocarbon; Battle of Stepney; Infantry Tank; SOLVED
No 3 – 1750; 1104; 1864; 4892; SOLVED
No 4 – 1692; Easter Island; Cauldron subsidence; Harry Potter; SOLVED

Points .. Well done all

Kelda  4 points

Volcanic 2 points

Stephanie Alice Halford 1 point

Inge B 1 point

Kilgharrah