Eruptions


Tourists hiking next to an active lava flow on Pacaya in Guatemala in 2006.

I’m flying back to Ohio today after a successful few weeks of fieldwork/paper writing. Apparently I have a pile of tomatoes waiting in our garden in Granville … !

On to news:

Comments

  1. #1 mike don
    July 23, 2010

    Considering that the eastern DRC/Rwanda/Uganda area near Nyiragongo has been in effect a war zone for much of the last fifty years. I wonder how many visitors that tour company is expecting?

  2. #2 mike lyvers
    July 23, 2010

    The volcanoes mentioned are far less dangerous than the risks involved in getting to them – such as the risk of a fatal car or bus crash, or of getting robbed or worse. I remember hiding from gun-toting bandits on Pacaya and then later, at the summit while minor explosions hurled lava bombs above me, feeling that the crater rim was far safer than the base of the cone, where the bandits were firing their pistols directly at fleeing tourists.

  3. #3 Birger Johansson
    July 23, 2010

    To help Iceland cash in on the volcano tourism, I vote we set up a pipeline to the Eyafjallajökull crater and pump in some smoke generating volatiles. As the sun shines on the smoke column near midnight, add thunder sound effects = Profit.

  4. #4 JulesP
    July 23, 2010

    There is a continued earthquake swarm in Iceland at the Tjornes fracture zone with 2 large quakes of @3.4 and 4.1.

    I am curious about how you can tell if this is tectonic or volacanic in origin- which graphs show depth of quakes? Many thanks

  5. #5 JulesP
    July 23, 2010

    Correction – the graph now only shows ONE large quake at 4.1, so perhaps this was an error they corrected.

  6. #6 bruce stout
    July 23, 2010

    @ Birger! Ha! failproof!

    @ JulesP all the data you need are on another tab on the IMO site here:
    http://en.vedur.is/earthquakes-and-volcanism/earthquakes/#view=table

  7. #7 Zander
    July 23, 2010

    I’m surprised noone has been up to Lake Eyjafjallajokull
    and posted photographs since it’s more placid these days.

  8. #8 Lurking
    July 23, 2010

    Not really sure where to put it, so I guess this will work.

    Perspective View – Grimsey, quakes for the last 2 to 3 days

    i25.tinypic.com/33yqqmv.png

    Grimsey, time vs depth, 18th to 23½ July

    For comparison, same plot but for the the last batch of activity uptick in Grimsey, 26 May – 1 June

    i28.tinypic.com/1z67dpj.png

  9. #9 Henrik, Swe
    July 23, 2010

    Suggestive plots Lurking, thanks! Wonder what the Icelanders will call the new island? ;) ;)

  10. #10 mjkbk
    July 23, 2010

    Update from Long Valley Observatory, as of today:
    http://volcanoes.usgs.gov/lvo/
    Hmm, the two largest quakes in this sequence are among the three biggest since 2000. Still, “This level of activity is considered normal for the area.”

  11. #11 Kultsi, Askola, FI
    July 23, 2010

    @Lurking [8] -
    The comparison plot URL is there but the July plot URL has gone missing…

    The perspective view does, indeed, suggest a pipe; would including the previous swarm be a bother?

  12. #12 Reynir, NK, .is
    July 23, 2010

    Ta for the Mozilla link up-blog, Raving. That might very well be the cause of the Flash hang-ups, as I almost always use multiple tabs in Firefox. Heh. I’ll just use it as an excuse for disabling Flash in ‘Fox, and then use Flock for Flash content.

  13. #13 Passerby
    July 23, 2010

    If you follow the hyperlink in #10, above, you’ll see that the USGS does indeed listen attentively to public feedback and respond quickly and affirmatively.

    LVO Friday July 23rd activity update..included the desired mention of other data collected at Long Valley but not referenced in their weekly reports of the last several years.

    THANKS USGS-LVO webteam! You GUYS ROCK!!

  14. #14 stigger
    July 23, 2010

    a 6.9 EQ off the coast of the Philippines http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/us2010zbbz.php and a 3.5 off the Californian coast near SF.

  15. #15 Renato Rio
    July 23, 2010

    @Lurking: you got another deep-focus to add to your plots. 603.8 km 6.9 mag. MORO GULF, MINDANAO, PHILIPPINES (USGS)

  16. #16 EKoh
    July 23, 2010

    @13 Passerby, I noticed the new detailed update as well. Thanks LVO team.

  17. #17 stigger
    July 23, 2010

    USGS have upgraded the Philippines to a Magnitude 7.3

  18. #18 Renato Rio
    July 23, 2010

    #15 Magnitude for Philippines EQ upgraded to 7.3. If it weren’t for the depth it would have caused pretty big damage.
    @EKoh: when you have a free time you could tell us something about these deep focus EQs typical to subduction zones. :)

  19. #19 Lurking
    July 23, 2010

    @Kultsi, Askola, FI [11]

    Odd…

    Here is the missing link. Dunno where the other one went to.

    http://i25.tinypic.com/2ujjspc.png

    Could have been a brain f@rt on my part… this has been an odd Karma day. Had a tractor tailor rig go into a jackknife 40 feet in front of me in driving rain today… he saved it but the pickup that had just cut me off nearly soiled himself. The rig saved it, the pickup pulled off to clean his drawers, and I made it around the whole non-mess. I’m still trying to figure out if it was good or bad karma. Bad that it happed, yes, but everything finished up with no damage other than nerves… and a pair of soiled underwear. That would be good karma.

  20. #20 Passerby
    July 23, 2010

    Deep Focus EQ mineralogy catalysis technobabble from Geology.com

    geology.about.com/od/earthquakes/a/aa_deeEQs.htm

    I too would like to hear from Ekoh on the more recent developments in this field.

  21. #21 ahhhhheq
    July 23, 2010

    So there have been 2 aftershocks that are greater than 7 magnitude…are such large aftershocks normal for really deep earthquakes like that?

    I am an obsessive worrier…

  22. #22 Renato Rio
    July 23, 2010

    #21 It’s a cluster of 7+ deep focus! Amazing!

  23. #23 Erik Klemetti
    July 23, 2010

    Renato … the USGS Twitter EQ feed agrees:

    http://twitter.com/usgsted

    Strange stuff in the Philippines.

  24. #24 Renato Rio
    July 23, 2010

    Truth is that we know very little about our planet. How can we talk about fluid mechanics being applied to the mantle, when we have thrust EQs occurring so deep?

  25. #25 Renato Rio
    July 23, 2010

    In the meanwhile, PHIVOLCS finds time to “commemorate”…
    “16 July 1990 Luzon Earthquake Marks Its 20th Year
    To commemorate its 20th year, PHIVOLCS will be holding a symposium on 15-16 July 2010 at PHIVOLCS Auditorium, Quezon City.”
    http://www.phivolcs.dost.gov.ph/index.php?option=com_frontpage&Itemid=1

  26. #26 Renato Rio
    July 23, 2010

    #25 I mean, there’s no update on EQs activity in the website.

  27. #27 Passerby
    July 23, 2010

    Actually, there have been three large quakes, varying in depth from 575-616 Km in depth, 3 at 7.3-4 Mag!

    Quite interesting. Background reading:

    Quickie abstract, that mentions similar type deep quakes in the same location, but with respect to the devastating shallow earthquake in this bench/trench. What happens if it’s a shallow quake: the most destructive quake in modern times in the Philippines.

    The 1976 August 16, Mindanao, Philippine earthquake (Msw 7.8) — evidence for a subduction zone south of Mindanao.
    Geophys. J Royal Astronom. Soc. 57:51 – 65

    Summary. The Philippine earthquake of 1976 August 16, is one of the largest to have occurred world-wide in recent years (Mw=8.8; Ms=7.8; seismic moment, Mo= 1.9 × 1028dyne-cm). It is, however, associated not with the Philippine Trench, which is the dominant tectonic feature along the eastern Philippine Islands, but with a much less prominent trench system in the Moro Gulf, North Celebes Sea, south of Mindanao. In this area most of the seismicity is at depths greater than 500 km, associated with the westward dipping Benioff zones of the Sangihe and Mindanao arc systems. This event, however, has a shallow focus and caused a locally destructive tsunami. …Bathymetric data indicate the presence of a trench striking north-south in the region of the Moro Gulf, and seismic reflection profiling indicates disturbed sediments east of the trench showing evidence for subduction. In addition, the geological structures mapped on the island of Mindanao are consistent with this mode of deformation. The only other known large earthquake in the region on 1918 August 15 (Ms=8.0) probably occurred along the same subduction zone, on an adjacent segment, to the south of the recent event.

    Note the dates. It is also instructive to recall that the large EQ under Granada Spain in April 2010 was also very deep, at ~630Km (estimated by IGNV, USGS and Harvard). A previous deep quake hit the same location in 1954, also at a deep depth of ~650Km.

    This webpage also describes the same Moro Gulf EQ described in the abstract above, but has a useful geological setting descriptive/graphics section at the bottom of the page.

    http://www.drgeorgepc.com/Tsunami1976Phillipines.html

  28. #28 Renato Rio
    July 23, 2010

    @Passerby: thank you very much for the feedback. Hope there won’t be damage from these ones. USGS “Did you feel?” map shows it has been felt as a mag. 5+ at the surface. Deep Focus EQs are the only type of big ones we have in Brazil, up to mag. 7 along the subduction of Nazca under S. American Plate. Since they happen in the middle of the Amazon forest, it’s never really felt. A mag. 8+ occurred in La Paz, Bolivia, with little damage as well. But these quakes can be felt from very far away.

  29. #29 Passerby
    July 23, 2010

    Yes, there was a very large deep focus EQ in Bolivia, in the mid-8s Mag range. It’s mentioned on the geology.about.com webpage.

  30. #30 Renato Rio
    July 23, 2010

    What intrigues me is the fact that the mantle isn’t supposed to be that brittle at such depths and I don’t quite understand the mineralogical explanations I’ve been reading, saying there’s a “changing” in the brittleness of mantle at these depths. But it kind of puts all plate tectonics theory at stake, don’t you think? In other words, mantle could be that brittle elsewhere. I don’t know if I’m being quite clear about this.

  31. #31 Passerby
    July 23, 2010

    http://neic.usgs.gov/neis/eq_depot/2009/eq_091004_mia8/neic_mia8_d.html

    Magnitude 6.6 MORO GULF, MINDANAO, PHILIPPINES
    Sunday, October 04, 2009 at 10:58:00 UTC, depth 620Km.

    So, USGS, we have 3 abutting ruptures?

    Number of global EQs on USGS map jumped from 535 to 834 in 20 min.

  32. #32 Renato Rio
    July 23, 2010

    According to EMSC there have been six big jolts, all 500-600 km deep. It’s a thrust faulting pattern, isn’t it?
    http://www.emsc-csem.org/index.php?page=home#2

  33. #33 Renato Rio
    July 23, 2010

    #31 Wow!

  34. #34 Passerby
    July 23, 2010

    @33 Technical issues with the website autoupdating.

  35. #35 Renato Rio
    July 23, 2010

    @Passerby: the technical babble happens to be very interesting, indeed. If you allow me I’ll paste some of it from
    http://geology.about.com/od/earthquakes/a/aa_deeEQs.htm
    “Over a wide depth range averaging 410 km, olivine begins to change to a different crystal form identical to that of the mineral spinel. This is what mineralogists call a phase change rather than a chemical change; only the volume of the mineral is affected. Olivine-spinel changes again to a perovskite form at around 650 km. (These two depths mark the mantle’s transition zone.)
    Other notable phase changes include enstatite-to-ilmenite and garnet-to-perovskite at depths below 500 km.
    (…)
    Then the great Bolivia deep earthquake of 9 June 1994 occurred, a magnitude 8.3 event at a depth of 636 km. Many workers thought that to be too much energy for the transformational faulting model to account for. Other tests have failed to confirm the model. But not all agree. Since then, deep-quake specialists have been trying new ideas, refining old ones, and having a ball.”

  36. #36 Lurking
    July 23, 2010

    Not much to look at… but here they are:

    Mindanao, Philippines

    View North

    http://i28.tinypic.com/24cco7o.png

    View East

    http://i26.tinypic.com/nwjzo0.png

  37. #37 Passerby
    July 23, 2010

    >But it kind of puts all plate tectonics theory at stake, don’t you think? In other words, mantle could be that brittle elsewhere. I don’t know if I’m being quite clear about this.

    Huh??

    Stop babbling. Start reading.

    Mechanism of Deep-focus Earthquakes Anomalous Statistics
    March 2010.
    http://arxiv.org/ftp/arxiv/papers/1003/1003.4448.pdf

  38. #38 Renato Rio
    July 23, 2010

    @Lurking: I knew you were already working on this!
    BTW, Where did you get the shallow ones from?

  39. #39 Renato Rio
    July 23, 2010

    @Passerby #37 You bet I will. I promise this is it (my babbling) for now: lot of homework to do. I’ll be munching on this overnight. Thanks again.

  40. #41 Renato Rio
    July 23, 2010

    #40 @Lurking, sorry, I didn’t get the shallow ones. These data are all from today’s activity? I only see deeper than 500 km.

  41. #42 Renato Rio
    July 23, 2010

    And @Lurking, I’m sorry for the bad day you had. You’re lucky to have an efficient “guarding angel”.

  42. #43 Passerby
    July 23, 2010

    Luckily, Ekoh prepped us for this.

    Tectonic setting of a composite terrane: A review of the Philippine island arc system. Geosciences J. 12:7 − 17, March 2008.

    http://www.geosciences-journal.org/home/journal/include/downloadPdf.asp?articleuid=%7BD4C09BA4-1A26-442C-8CDD-6D37C0FB21B7%7D

  43. #44 parclair, lost in the ether
    July 23, 2010

    Sakurajima’s been erupting pretty much constantly the last half hour or so….

    http://webcam-svo2.pr.kyoto-u.ac.jp/local/camera.html

  44. #45 Doug C.
    July 24, 2010

    Those Philippine quakes show up really well on the Redoubt Webicorder, with a lag-time of around 11.5 minutes.
    http://www.avo.alaska.edu/webicorders/Redoubt/RSO_EHZ_AV.php

  45. #46 EKoh
    July 24, 2010

    Seismology and mantle dynamics are not my specialty. However, these deep focus quakes were known before subduction was understood, in fact the dipping plane of very deep quakes, known as the Wadati-Benioff zone, was one line of evidence for subduction. What is happening is that you are thrusting colder and more brittle oceanic crust deep into the mantle.
    Now as for the exact quake mechanisms and patterns of quakes, we’ll need to heat from a geophysicist.
    BTW, the tectonics of the Philippines are complex to say the least. I believe there are two subduction zones converging on either side of the islands.

  46. #47 Lurking
    July 24, 2010

    @Renato Rio

    Not necessarily today’s quakes. I plotted the entire list then set lat/lon boundaries to get the Mindanao area. If they were in the list, they are in the plot.

    As for the bad day… it’s a Karma thing, and like I said it’s hard to call if it was bad or good. Everybody recovered control and nothing was damaged. So that would be good.

    Let’s just call it and “interesting” day.

  47. #48 Lurking
    July 24, 2010

    A Perspective Plot of Grimsey area looking North East.

    A very interesting plot, sort of looks like layers of faults with the nearby stacks.

    http://i31.tinypic.com/15gq9dx.png

  48. #49 Dennis
    July 24, 2010

    nice perspective, thanks Lurking.
    Whats about changing the color bar from depth to time.
    At your last one it could be a too much data, but at #36 it would increase the information.
    Sorry if i missed it, had you also plotted the Fox Islands, Alaska quakes?
    Thanks again for this great blog, interesting ideas, nice comments and wide knowledge.

  49. #50 Renato Rio
    July 24, 2010

    6.4 in Iceland!
    Saturday
    24.07.2010 12:04:15 64.038 -21.231 1.3 km 6.4 mag 55.89 4.7 km SSW of Hrómundartindi

  50. #51 Renato Rio
    July 24, 2010

    The EQ occurred at Reykjanes ridge, but neither EMSC nor USGS say anything about it.

  51. #52 Renato Rio
    July 24, 2010

    #50 Ok, they’ve just downgraded it. I think they’ve switched the figures (depth x magnitude). False alarm.
    Saturday
    24.07.2010 12:04:15 64.048 -21.240 6.2 km -0.2 99.0 3.9 km SSW of Hrómundartindi

  52. #53 Clown
    July 24, 2010

    http://hraun.vedur.is/ja/englishweb/eqlist.html
    12:04:15,4 64,038 -21,231 1,3 6,4 55,89 4,7 km SSW of Hrómundartindi

    here its still the 6.4

  53. #54 Renato Rio
    July 24, 2010

    I’m happy it was no 6.4. At this depth (1,3 km, as the original plot) it would have been a mess at the surface.
    But we got some small ones in Godabunga and Hekla.

  54. #55 parclair NoCal USA
    July 24, 2010

    Chris Rowan over at Highly Allochthonous has an interesting discussion of the complexity of the Phillippines fault area:

    http://all-geo.org/highlyallochthonous/2010/07/fridayish-focal-mechanisms/

  55. #56 Lurking
    July 24, 2010

    @Dennis

    I generally stick to simple scatters plots, but since the view only uses 2 axis, I can cheat and make the 3d into a time stamp. Sort of cumbersome since two separate plot runs have to be done, but possible.

    View North

    http://i30.tinypic.com/10mk6dd.png

    View East
    http://i27.tinypic.com/2wg6psw.png

  56. #57 Renato Rio
    July 24, 2010

    Google translated from IMO website:
    “07/23/2010: Earth tremor cycle began island northeast of the second part yesterday and it still stands.
    So far this day has been recorded more than 70 earthquakes in this region. The largest quake was at this morning. 08:38 and he was four points.
    No reports have been received from the island to the quake has been found. Most of the quake are 10-13 km depth. Earthquakes are common in this area.”
    http://www.vedur.is/um-vi/frettir/2010/nr/1962

  57. #58 Diane N CA
    July 24, 2010

    From the last thread, on the quake off shore near SF, it is on the San Andreas and probably doesn’t mean much. It is near the ’06 epicenter. The one they now say was the epicenter of the ’06 quake is almost dead center off the Golden Gate. They used to say the epicenter was on Pt. Reyes were Earthquake Trail starts. I have walked the trail and it is interesting to see the offset fence, the escarpment and the spot where you can straddle the two plates.

    Will there be a big one? One of these days there will be. Nobody knows when so any chatter about it is just that. Chatter. I wish there wasn’t so much hype about it. The best anyone can do right now is have some plan of what to do when it does happen. Other than that, we can’t live in fear all the time.

    I live in an area where there is a fault. Several in fact and I can see them in the road cuts. There is a spring that is above the road in one place and the spring is on top of the hill. At times, water will drain through a crack in the road, but for the time being it is dry.

    Another thing about another area of CA that is near me is the drain that was put in to drain a mine on which several homes and appartments are built. The two holes that drain the mine run down the side of the road to a drainage and it is always running (more like trickling) and is some pretty nasty stuff with a lot of iron in it because of a lot of stuff was left in the mine. If a major quake hit the area, that part of town would look like No Name City.

    Right now, I have decided to embark on my own exploration of the geology in my neck of the woods and learn more about it. I already know a bit, but I want to know just what I am looking at in the road cuts and also underneath. I can do that partly with a geologic feature map, but I want to do some field work on it, too. There is a lot of different stuff here. I want to document it even if it has been done before. There is a feature near where I live that most of the people around here don’t know about. I would like to get an article about it in the local paper. Eh, some day.

  58. #59 Renato Rio
    July 24, 2010

    #56 It seems clearer now, Lurking. At least to me. It gives the impression the subducted slab is “sinking” northwards and is bent at its deeper edge. But this is a total guess.

  59. #60 Renato Rio
    July 24, 2010

    @Diane: nice summer plans, for what you say. It would be nice to take some shots of the observed areas and keep them as a comparison for when you go back next time. Of course, you must have that already in mind, but I remember my father doing this kind of work. He was an Engineer, specialized in Soil Mechanics and a Geology freak. I wish he had lived longer so I could have learned more with him. Still keep his photo collections, but don’t find the references to them. He had predicted, back in the 70′s, landslides and other hazards that are taking their toll to people living on slopes in Rio today.

  60. #61 Renato Rio
    July 24, 2010

    #55 #56 @parclair
    Thank you for the link, I’ve just read it to learn my interpretation of @lurking’s plots is incorrect. The slab is supposedly moving westwards, for what I could understand. Better shut my mouth and leave the interpretations for experts. But @Lurking, thank you anyway.

  61. #62 Passerby
    July 24, 2010

    For Diane:

    Over this USGS seismic map
    earthquake.usgs.gov/earthquakes/recenteqscanv/

    with this CA-NV geothermal plant location map
    http://www.nevadageothermal.com/i/maps/operatinggeothermal.gif

    to view location connection between clustered EQ activity and geothermal field proximity.

  62. #63 stigger
    July 24, 2010

    If any of you are in England this summer, there is a fabulous exhibition of Volcano art from 16th Century engravings through the genius of Turner to the sublime wonder that is Warhol.
    On until 31st October
    http://www.comptonverney.org.uk/?page=exhibitions/volcano&type=banner1

  63. #64 Alyson
    July 24, 2010

    There’s a whole lotta shakin’ going on! First it was Fox Island with very consistent 10km depth quakes, then California, and now a lot of shallow quakes around Greece and the Med, interspersed with the very deep ones near the Phillipines. Hopefully it will settle a bit now.

  64. #65 Renato Rio
    July 24, 2010

    #63 Thank you, @stigger. It makes me curious as to see Warhol’s view over volcanoes.

  65. #66 Lurking
    July 24, 2010

    @All

    Coming up with the bright idea of trying to replicate Figure 6 from the “Mechanism of Deep-focus Earthquakes Anomalous Statistics” document linked by Passerby [37], I first ran a quick depth vs Mag plot to see if there were enough points in the USGS database for this little area to make it worth the trouble.

    There aren’t. But it does make a nice plot. Bounding box of 123E to 124E – 6N to 7N, USGS listed quakes 1973 to present. Recent activity plotted in blue.

    Depth vs Magnitude.

    http://i28.tinypic.com/29y4jut.png

    @Dennis

    Sorry, I misread your question about the color = time and mistakenly thought you were referring to the Mindanao quakes.

    I can do a similar plot of Grímsey, but can’t get the whole shebang to work in a 3D view. I haven’t mastered the 4D aspect of the program, and each time I try I get something I didn’t expect.

  66. #67 Renato Rio
    July 24, 2010

    @Lurking: Thanks again. I can see two clear depth lines: one from quakes ranging from ~35-65 km and another from ~590-620 km. right?

  67. #68 Diane N CA
    July 24, 2010

    Renato #60, thanks for the cudos. I forgot to write down where I got the first set of pictures :-}, but at least I can find them again. And I didn’t take enough film! Rats. Next time. I need to get a digital camera!!!

    @Passerby #62, thanks for that map of the geothermal plants. I had no idea there were that many. I can say the one that is the Geysers generates a lot of quakes. I was suspecting the Coso plant to have something to do with the quakes in Long Valley, but I am not sure just how far the swarm is from the plant. I have occasionally seen a small quake or two where I think the plant is, but I am not sure on that. Right now I am suspecting some hydrothermal activity in Hot Creek which is normal for that area as there can be a deadly rise in water temp without warning. I guess people still want to take their chances, but since I have been there, I think they have blocked it off so you can’t get into the water. That water can go from nice warm bathtub temp to over boiling in seconds.

    I still want to go back to Long Valley, but there is a lot of interesting geology at home. So I will be taking pics and documenting what I find in a better form than I have been as of late. This is something that I just got the idea to do so it is a work in progress.

  68. #69 Dan, Florida in UK
    July 24, 2010

    Hi all, still alive here.
    @63 stigger I happen to be in England at the moment. I would love to be able to go see Compton Verney, but it is the wrong way from where I am in Basingstoke, west of London. Have been gone since 14 July. Am enjoying the cooler weather (actually, been cold on more than one occasion) and also getting away from the oil news. Although I still keep up on what is happening, it has taken a back seat to my vacation. Still have a couple of more weeks before getting back to the homestead.

    Cheers
    (I think I’m finally getting the hang of this language over here) :)

  69. #70 stigger
    July 24, 2010

    @69 Dan (Florida in UK). Coincidence! I only live 12 miles from Basingstoke and yes, it is fairly cool weather at the moment. Compton Verney is only 2 hours by car (I went yesterday) saw it advertised whilst visiting the University of Warwick and called in on my way home. Worth a visit if you could arrange it.

  70. #71 Lurking
    July 24, 2010

    @Renato Rio

    I wouldn’t rally call them “lines”.. more like groups. Also, you might take the depth values of the shallower quakes with a grain of salt, when they start coming out all at the same value I grow suspicious of instrument errors… especially when you are also looking at 37 years of technology changes in the data.

    Shallower quakes are more difficult to nail down due to the higher levels of noise introduced by the strata. (more reflection points etc…)

    Though not a geologist I am very aware of the difficulties of digging a signal out of clutter.

  71. #72 Dan, Florida in UK
    July 24, 2010

    @70 stigger Small world isn’t it?
    And “fairly cool weather” is a relative term. :) But I must say, even when it warms up, I love the dew point/humidity here.

  72. #73 stigger
    July 24, 2010

    @72 Dan: ’tis a small world indeed!
    Are you on holiday or working over here?
    Only visited Florida once but yes, the humidity is very different in Hampshire.

  73. #74 Renato Rio
    July 24, 2010

    @Dan, I’m glad to hear your fairing well in the “foggy” city. Wait till the “storm” is over and I’m hoping that, at the end, it will all have been but a nightmare. :)
    @Lurking, thanks for the precious info. As we have seen earlier today, we can’t thrust shallow-quake plotting.
    @All Saturday night fever here in Rio, so you won’t be hearing from me till tomorrow. Have a good night! <:}

  74. #75 Passerby
    July 24, 2010

    So we can do a little bit of comparison, graphically. First, we go to the tsunmai webpage and pull the figure

    Distribution of earthquake hypocenters along a section of the Cotabato Trench subduction boundary (After B. Bautista 1996, PHIVOLCS)

    http://www.drgeorgepc.com/Tsunami1976Phillipines.html

    This gets flipped on it’s side, so depth is on the x-axis.
    We then paste in Lurkings figure and stretch it to match the depth axis readings from the figure above. They are laying side by side, with Lurkings on top.

    Then we go to the elegant Russkie paper, Mechanisms of Deep Focus..from my post (38), Fig 6, which we grab using a graphics capture program. We paste it into our figure, right on top of the other two, about in the middle, and we shift it’s layer transparency to allow us to see the underlying figures.

    What do we see?

    We see that the Russkies are indeed correct, in fact, we’ve proved their model with the data from Phivolcs and USGS – that the effective plastic deformation length, gamma, is indeed at 200km, because our graph shows that below the surface brittle layer fracturing at 50klicks, we have EQ nodes (clusters) at 200, 400 and 600 kms.

    Freaking unreal.

    I’ve written to the authors to let them know. We’ve just made a bit of science history. Good job!

  75. #76 Passerby
    July 24, 2010

    To be politically correct, the authors institutional affiliations are in the Ukraine, Bulgaria and Macedonia.

  76. #77 Passerby
    July 24, 2010

    I’m going to start pointing to other Sciblogs that are I have found to be exemplary in their quality, subject choices and professionalism. Some have been posting for years, some are relatively new.

    One of them is the SETI blog.
    http://scienceblogs.com/SETI/

    I hope they continue to post here.

  77. #78 Lurking
    July 25, 2010

    BTW Passerby… if you need an of those data points knocked down in size to a facilitate there use, feel free to ask. I used a bit larger symbol than normal to get them to stand out.

  78. #79 Lurking
    July 25, 2010

    How did that parody of Metallica go? Oh yeah, “Beer Good, FIRE BAD!!!”

    Let me try that again:

    “BTW Passerby… if you need any of those data points knocked down in size to a facilitate their use, feel free to ask. I used a bit larger symbol than normal to get them to stand out.”

  79. #80 mark t burns
    July 25, 2010

    Dude, I don’t care what you say, Katla is getting ready to blow. It will start like Eyjafjallajokull with a fissure opening on the northwest flank. When? Probably before the end of this year. I’m guessing sooner. Take that.

  80. #81 Lurking
    July 25, 2010

    Gonna need some quakes to evidence that.

    Katla blows when Katla blows. Does it quite often… but only does it when she’s ready. On average, about every 64.5 years, give or take a few standard deviations (48.3years).

    The last was in 1999. Can it happen? Yup. But your gonna need a flurry of activity to accurately say “here is comes.”

  81. #82 Henrik, Swe
    July 25, 2010

    Lurking, people tend to believe what they want to believe no matter what the best interpretation of available evidence by the most qualified specialists. In one respect Mark T Burns is correct – every volcano not currently erupting is “getting ready to blow”. Eventually, even once-only events such as cinder cones will blow too, albeit it may be 5,000,000,000+ years before their material is thus regurgitated. Within 10,000,000,000 years, the area where NYC of today stands will have been flattened by a large meteor, asteroid or comet. The surface and oceans of Earth will be vaporised and disappear into space when our sun dies. In 10 to the 135th power years, even the most massive black hole will have evaporated. The Universe itself will die given enough time.

    You and I know that we will never witness these events (bar possibly an eruption of Katla, which *may* erupt before the year is out even if that’s unlikely), yet there are people who want to believe that this will take place soon, within our lifetime. What is of interest though, is the undelying psychological motivations for such wishes…
    ;)

  82. #83 thor
    July 25, 2010

    Katla will, blow when Nature let her blow,. before that, I holds my bets On Eyjafjöll, she is more belivable to make a new appearance…

    even Vatnajökull can make an appearance,and every other Volcano on Iceland conected to the Mid Atlantic Ridge,..

  83. #84 Carl on the Sea
    July 25, 2010

    If you look at Iceland as a large volcano it get’s a bit easier to predict an eruption:)
    The statistical chance based on eruptions during the last 1000 years and then adding some outlayers for those volcanoes that haven’t erupted during that time but figures exist for then you get an 83% chans of eruption withing 5 years, and 9,7% that Iceland will blow before july 2011.

    Likelihood of Katla bopping statistically is 1,8% per year, and if you count in the low activity at Katla then we are really down in the statistics. So if someone wants Katla do dance the Bopp-a-lula then you will have to give her a Beer.

    My preferred candidates of an eruption are in order of likelihood, Askja, Reykjaneshryggur, Bardarbunga and Lakagigar.
    Among those that would produce “The most interesting times” would be Bardarbunga, Lakagigar and Askja. Both Askja and Bardarbunga are showing some signs of increased risk, such as land rising upwards and increased quakiness (slight).

    Perversely enough, I really would like to see a new ultra-scale fracturing that permited all the pent up energy-potential of the 60+ metre uplifting of Iceland to be released. Then we would see something like 5.200 cubik kilometres of lava being pushed out:) We could always name it Nornagigar;)

  84. #85 Lurking
    July 25, 2010

    @Carl on the Sea

    Wait a minute…

    “…all the pent up energy-potential of the 60+ metre uplifting of Iceland to be released…”

    Your kidding right? Is that in the Bardarbunga area?

    60 meters uplift. That’s a lot of magma, or a sizable crustal rebound.

  85. #86 Renato Rio
    July 25, 2010

    “Góðan dag allir!”
    For what I can tell, you people are pretty much in an Icelandic mood today. Time for a question: why isn’t Hvolsvöllur cam working for me? There’s a very interesting fog over Gigi today (frá Thórolsfélli) and I wish I could see more of what’s going on. As for Eyjaf, my hopes on a revitalizing are fading away. Katla? Nothing, but a wonderful peaceful view from the cam (hope it stays that way, which is quite likely).
    @Henrik, Swe:
    “What is of interest though, is the undelying psychological motivations for such wishes…”
    I have my own speculations over the subject, but posting them would be too much off-thread. Interesting the way you summarized it, though…

  86. #87 Renato Rio
    July 25, 2010

    @Carl on the sea: Why isn’t Hekla on your list? It has erupted in a ten year interval before (1970, 1980, 1991 and 2000). I wouldn’t discard Hekla from my list (not a wish here, Henrik, mere speculation on previous evidence). ;)

  87. #88 Kultsi, Askola, FI
    July 25, 2010

    @Renato -

    The Hvolsvöllur cam seems to be on the fritz, does not work for me either. Nothing so see, anyway, as verified by the Thórólfsfell and Múlakot views.

  88. #89 Renato Rio
    July 25, 2010

    @Kultsi: Thank you very much. I didn’t know that Mulakót cam was back. Let’s hope Mila will fix Hvolsvöllur’s so we can go on speculating.

  89. #90 bruce stout
    July 25, 2010

    Did I ever say this place is the coolest place in town?
    really, great stuff. I’ve got two papers downloaded for bed-time reading tonight and looking forward to it.

    Re these Philippine quakes:
    I’d love to know what’s happening down there at the transition zone. They say the lower mantle is much less viscous than the upper mantle so the first idea is that the quakes are the result of the subducting plate ramming into something harder and tougher than itself. Whether this is locally the case though is moot. I could also imagine that a subducting plate is so cool that it just ploughs straight down into the lower mantle like those images we saw of the Farallon plate under North America without being particularly affected by the transition zone. The question then would be, why the quakes? At that depth there is probably not a lot of bending going on unless of course, (back to first hypothesis) the plate is indeed colliding off the denser lower mantle at this depth. hmm. fascinating stuff.
    Got the Romanian/Ukrainian paper for bed tonight. Perhaps that sheds some light on it.
    You guys rock!

  90. #91 stigger
    July 25, 2010
  91. #92 Stefan
    July 25, 2010

    hi all together

    i’ve been in iceland for the last two weeks and enjoyed the wonderfull landscape.

    as point of interest i made a hiking tour with my father up to the thorolfsfell tablemountain and to the webcam.

    that must have been on monday two weeks ago. i hope somebody was able to see that the cam was cleanded a bit :) there was some dust and dry water drops on the lens and myself as a watcher wanted to give all the people who watch eyjafjallajökull a nice clear view to the volcano.

    i try to post a picture of the webcam/mobilestation later, so that you guys at least get an idea how it looks up there. the volcano itself is still emitting quite a bit of steam, but nothing more :)

  92. #93 stigger
    July 25, 2010
  93. #94 stigger
    July 25, 2010

    Whole lot of action in the Philippines; variable depth
    # KURIL ISLANDS (Map: bit.ly/90m9Bf ) 2010-07-25 12:57:00 UTC | Depth (km): 119 | Mag: 5.8 | #Earthquake 1 minute ago via apiaccess

    # MORO GULF, MINDANAO, PHILIPPINES (Map: bit.ly/d92uVs ) 2010-07-25 08:18:29 UTC | Depth (km): 618 | Mag: 5.2 | #Earthquake 1 minute ago via apiaccess

    # TAIWAN (Map: bit.ly/cPPLj9 ) 2010-07-25 03:52:12 UTC | Depth (km): 36 | Mag: 5.4 | #Earthquake 1 minute ago via apiaccess

    # TONGA (Map: bit.ly/aYfRn8 ) 2010-07-25 03:39:23 UTC | Depth (km): 47 | Mag: 6.0 | #Earthquake 1 minute ago via apiaccess

    # SULAWESI, INDONESIA (Map: bit.ly/ceW1jZ ) 2010-07-24 23:51:12 UTC | Depth (km): 33 | Mag: 5.1 | #Earthquake 1 minute ago via apiaccess

    # OFFSHORE O’HIGGINS, CHILE (Map: bit.ly/ar9el5 ) 2010-07-24 21:46:36 UTC | Depth (km): 10 | Mag: 5.2 | #Earthquake 1 minute ago via apiaccess

    # CHAGOS ARCHIPELAGO REGION (Map: bit.ly/ac5vhe ) 2010-07-24 20:28:09 UTC | Depth (km): 33 | Mag: 5.4 | #Earthquake 1 minute ago via apiaccess

    # NORTHWEST OF AUSTRALIA (Map: bit.ly/aGVfzq ) 2010-07-24 19:17:54 UTC | Depth (km): 2 | Mag: 5.0 | #Earthquake 1 minute ago via apiaccess

    # KEP. MENTAWAI REGION, INDONESIA (Map: bit.ly/bfv1vM ) 2010-07-24 15:17:50 UTC | Depth (km): 30 | Mag: 5.0 | #Earthquake 1 minute ago via apiaccess

    # MORO GULF, MINDANAO, PHILIPPINES (Map: bit.ly/bkhKuH ) 2010-07-24 11:56:25 UTC | Depth (km): 606 | Mag: 5.1 | #Earthquake

  94. #95 Lurking
    July 25, 2010

    Seriously… all you are gonna have to do is wait around a bit. There will be another.

    From a compilation of the eruptive histories from http://www.volcano.si.edu of four of the volcanoes in the area:

    2010 – Eyjafjallajökull
    2000 – Hekla
    1999 – Katla
    1991 – Hekla
    1981 – Hekla
    1980 – Hekla
    1970 – Hekla
    1955 – Katla
    1947 – Hekla
    1918 – Katla
    1913 – Hekla
    1878 – Hekla
    1860 – Katla
    1845 – Hekla
    1823 – Katla
    1821 – Eyjafjallajökull
    1766 – Hekla
    1755 – Katla
    1725 – Hekla
    1721 – Katla
    1693 – Hekla
    1660 – Katla
    1636 – Hekla
    1625 – Katla
    1612 – Katla
    1612 – Eyjafjallajökull
    1597 – Hekla
    1580 – Katla
    1554 – Hekla
    1550 – Katla
    1510 – Hekla
    1500 – Katla
    1477 – Torfajökull
    1450 – Katla
    1440 – Katla
    1440 – Hekla
    1416 – Katla
    1389 – Hekla
    1357 – Katla
    1341 – Hekla
    1311 – Katla
    1300 – Hekla
    1262 – Katla
    1245 – Katla
    1222 – Hekla
    1210 – Katla
    1206 – Hekla
    1177 – Katla
    1170 – Torfajökull
    1158 – Hekla
    1150 – Katla
    1104 – Hekla
    1050 – Hekla
    950 – Katla
    934 – Katla
    920 – Katla
    920 – Eyjafjallajökull
    904 – Katla
    870 – Torfajökull
    820 – Katla
    800 – Hekla
    780 – Katla
    750 – Hekla
    690 – Katla
    680 – Katla
    650 – Hekla
    610 – Katla
    590 – Katla
    550 – Hekla
    550 – Eyjafjallajökull
    540 – Katla
    500 – Katla
    400 – Katla
    350 – Hekla
    290 – Katla
    270 – Katla
    260 – Katla
    250 – Hekla
    200 – Katla
    150 – Torfajökull
    130 – Katla

  95. #96 Renato Rio
    July 25, 2010

    @Stefan #92: Yes, we all noticed the cleaning of Þórólsfell cam and we are most grateful to you. And yes, I would love to see the location of the cam and the other angles from there. Thank you very much.
    @Stigger and @Lurking: Thank you for the updates.

  96. #97 Renato Rio
    July 25, 2010

    @Lurking
    BTW I was just trying to locate Torfjökull and checking on recent quakes when I noticed another one near the glacier a few minutes ago:
    Sunday
    25.07.2010 20:19:08 63.922 -19.213 1.1 km 1.1 66.07 7.0 km N of Álftavatn
    And there was another NE of Eyjaf, with a deeper focus:
    Sunday
    25.07.2010 19:26:56 63.687 -19.371 8.7 km 1.0 51.16 5.5 km ENE of Básar

  97. #98 Passerby
    July 25, 2010

    @90: If you read those papers, some of your questions will be answered outright and others by examination of the figures (map graphic of deep focus EQs, in particular; the cited paper will appear in the Europhysics Journal in August 2010) and text references.

    See also: Chris’ Highly Allochthonous Friday post and take a long look at his map graphic – compare it to the Moro Gulf tsunami webpage graphics map with tectonic forces marked. You will see that the sequence follows a tightly curved progression, which is why I questioned whether there was snapping at several short segments of this curve zone.

  98. #99 Stefan
    July 25, 2010

    @Lurking / Post 95

    There are also some pretty devastating eruptions of Öræfajökull in the south-eastern region of vatnajökull natural reservat.

    they took place in 1362 and 1727.

    the eruption in 1362 was the largest explosive eruption in the last 1100 years in iceland. the eruption was of about the same scale like the eruption of mt. pinatubo on luzon.

    (in icelandic: http://www.islandia.is/hamfarir/jardfraedilegt/eldgos/oraefajokull.html)

    pictures:

    look towards thorolfsfell:
    http://img801.imageshack.us/img801/2640/igp3886.jpg

    look towards eyjafjallajökull with the station in the bottom left corner:
    http://img836.imageshack.us/img836/1118/igp3906.jpg
    http://img840.imageshack.us/img840/1200/igp3909.jpg
    http://img716.imageshack.us/img716/9285/igp3974.jpg

    a closer look on the station:
    http://img821.imageshack.us/img821/4734/igp3918.jpg

    actually the two cameras (normal right and infrared on the left):
    http://img840.imageshack.us/img840/9175/igp3940.jpg

    figures in the ash:
    http://img716.imageshack.us/img716/7020/igp3976.jpg

    and a last look on eyjafjallajökull:
    http://img836.imageshack.us/img836/2218/igp3952.jpg

    if there is a way to post thumbnails, let me please know!

  99. #100 Alyson
    July 25, 2010

    There are some amazing images of Kilauea at this link:
    http://hawaiianlavadaily.blogspot.com/
    - looking at Leigh Hilbert’s photography – linked from Highly Allochthonous.

  100. #101 Henrik, Swe
    July 25, 2010

    @ Stefan (#92). We did notice, much obliged!

  101. #102 Renato Rio
    July 25, 2010

    #99 @Stefan: Historical pictures for us over this blog. I’ll save them all, with your permission. Thank you very much, indeed.

  102. #103 Renato Rio
    July 25, 2010

    #100 @Alyson: Thanks for posting. Most amazing videos to the bottom of the webpage.

  103. #104 Lurking
    July 25, 2010

    @Stefan

    Thanks for the info and the nice shots.

    When I first did my list I only had the volcanoes on the SIL chart for Mýrdalsjökull to go by. (they were closest to the show and it was the source of the quakes I was plotting)

    From the setting, I imagine anything going off in and around Vatnajökull would be significant.

  104. #105 Passerby
    July 25, 2010

    @89: I didn’t know that Mulakót cam was back

    It’s not. Kulsti found and hacked the new site. It’s offline to the rest of us for reasons of security/privacy.

    We thank the webhosts at Mulakot for their patience and forbearance, in allowing us unfettered viewing access for four months.

  105. #106 birdseyeUSA
    July 25, 2010

    @stefan, thank you so much for the pictures -you let us know what it is like in the area from other angles, great. A nice clean camera eye also fine! : )

    Thanks from me as well to the Mulakot folks (sorry, on a traveling computer, no accents.)

  106. #107 Kultsi, Askola, FI
    July 26, 2010

    @105 The camera is available thru Jón’s site now, just like before. Using that path does not add traffic – except at Jón’s site at http://www.simnet.is/jonfr500/earthquake/vefmyndeyjafjalmulaen.html

  107. #108 Stefan
    July 26, 2010

    you can save the images if you realy want to ;) they are solely thought to be of a documentary character, therefor you can freely use them, exept selling them :)

    interesting for me was, that around the southcoast almost all the farmland look ash-free. but when its dry and windy there is some kind of a strange dust-/ash-/sandstorm which is pretty dens in some places. (there was a pretty heavy duststorm last thuesday on the skeidararsandur betwen myrdals- and vatnajökull)

  108. #109 Kultsi, Askola, FI
    July 26, 2010

    Looks like this creature with the nym about attracting pieces of metal is spamming around trying to peddle the s*t. It copy-pastes a part of former comment to sound credible.

  109. #110 Greg
    July 26, 2010

    I’d rather die seeing a volcano then die eating junk food and watching junk TV all day….

    Statistically, the car taking you to the volcano will more likely kill you.

    Nanny states should be banned.

  110. #111 Raving
    July 26, 2010

    Statistically, the car taking you to the volcano will more likely kill you.

    Posted by: Greg | July 26, 2010 8:32 AM

    No kidding! Mules are safer. :D

  111. #112 Lurking
    July 26, 2010

    Well, the flipping thing sure as @#$@# ain’t me.

    Generally when run across intrusive advertising it motivates me to avoid the product. I place advertising in the “theft of service” realm that is generally used for computer and network intruders. The advert impinged on my attention, and distracted me from more fruitful use of my thoughts and time.

  112. #113 Henrik, Swe
    July 26, 2010

    My thoughts exactly, well said Lurking!

  113. #114 Carl on Rödkallen Island
    July 26, 2010

    @85 (Lurking):
    Nope, the average uplift of Iceland is 60+ metres above earth average according to a new satellite gravitometric study. Here is a nice map from the GOCE satellite.
    http://news.bbc.co.uk/2/hi/science/nature/8767763.stm

    @87 (Renato Rio on Rialto):
    I actually forgot to put Hekla on my likely to erupt list;) Of course it should be there. That if anything is a “take a beer and blow” volcano. But, it tends to be a bit on the foppish side when it goes.

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