Some news for a busy Tuesday:
The crater at Poas volcano in Costa Rica, taken February 25, 2010. Image courtesy of OVSICORI by Federico Chavarria.
- After the MSNBC debacle, it is nice to see some good articles on why the Chilean earthquake was overall less disastrous than the Haitian earthquake, why the tsunami wasn't as large as predicted and why these earthquakes are not abnormal. There are a lot of factors involved - the location, depth, preparedness, wealth - so the comparison can be very telling in terms of both geologic and societal issues.
- The other scientific fallout from the Chilean earthquake will be a test of the volcano-earthquake connection suggested by Sebastian Watt in last year's EPSL article. According to Watt's (and others) research, we should expect to see an uptick in volcanic activity over the next year within 500 km of the epicenter of the earthquake - so watch places like Longavi, Descabezado Grande, Calabozos, Copahue, Chillan and Lonquimay amongst many others.
- Remember the spiders on Mt. Saint Helens, used to monitor the volcano? Well, they will be spreading to Chile to help monitor Chaiten. Two spiders will be set up on the rhyolite dome system to monitor changes in the domes - looking at seismic activity, deformation and explosions in the caldera.
- Dr. Boris Behncke has updated us on some of the volcanic activity in Costa Rica - including a phreatic eruption at Poas last week and increasing seismicity at Irazu. More on the earthquakes at Irazu can be read here. There is also a great set of aerial images of Poas and Arenal taken recently that were posted by OVSICORI.
- Eruptions reader Thomas Wipf left a link to a great video of Sakurajima in Japan erupting on January 16, 2010. Definitely worth the four minutes to see an impressive explosive eruption.
- It seems that activity at Mayon has settled down significantly as well, with PHIVOLCS lowering the alert status to Level 1 (of 3). Only about 5 volcanic earthquakes are occurring daily at Mayon and that the overall activity suggests a return to "normalcy". However, they do warn people to be careful in lahar-prone drainages near the volcano considering all the new, loose volcaniclastic material on the slopes of Mayon.
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I remember something about the spiders at Mt. St. Helens, but I have forgotten what they are. Will someone please let me know what they are? Yes, I know they are a monitoring device, I just don't know what kind. :-)
It will be an interesting watch to see what happens in the next few months with the volcanoes around the area of the quake. As John Seach said, there are 21 active volcanoes near the quake and aftershock areas which runs for 600km. A lot to watch. I just hope nothing big happens that will do a lot of damage. They have been hit pretty hard. But it would be nice if one erupted just enough to put on a show.
Diane - Oops! I meant to link to a post on the spiders and forgot. I've now added a link. Sorry!
Thanks Erik. I scanned the article and now I what they are doing. It is unfortunate that the quake has put off the placing of the "spiders". They need them.
Chilean Quake May Have Shortened Earth Days
ScienceDaily (Mar. 2, 2010) â
The Feb. 27 magnitude 8.8 earthquake in Chile may have shortened the length of each Earth day.
"the quake should have moved Earth's figure axis (the axis about which Earth's mass is balanced) by 2.7 milliarcseconds (about 8 centimeters, or 3 inches)."
Follow-up news story to the NPR link explaining the mis-read of tsunami severity, see: 'Scientists Defend Tsunami Warning', linked at the bottom of the webpage cited by Erik in his blog post. Salient points:
'Those models could be more accurate if scientists had more deep-water sensors and could build coastal inundation models for vast parts of the Pacific Rim where the topography hasn't yet been well-surveyed, Wang said.'
'Because complete data doesn't exist for every coastal area, scientists must play it safe in their wave predictions, he said.'
Ain't necessarily so. Coastal topology information (satellite and surveyed) is more than sufficient to model general inundation patterns over a stepped progression of wave and land elevations along high-value coastal segments. Deep water sensor network data capture can be boosted using relatively new network refining algorithm techniques like Compressed Sensing and Compressive Cooperative Sensing and Mapping in Mobile Networks.
These modeling and data enrichment exercises are important tools needed to forecast risk potential from large rogue waves and severe storm events.
OTOH, local officials should consider convening meetings to address what the issue a 'false alarm' on forecast wave-heights.
Emergency response management personnel should evaluate public response compliance to the evacuation order using a variety of data gathering instruments. The results provide important feedback to the ERM community because these severe wave events are sparse. Model refinement and validation by the forecast community is going to take time; meanwhile, Tsunami warning center officials will necessarily be conservative in their event forecasts.
By reinforcing understanding of the tsunami warning system limitations and briefing the public on success of local response, officials can underscore the importance of this learning and training exercise for forecasters and the affected public.
The broadcast warnings and large-scale evacuations in dozens of countries along the Pacific Rim on Saturday was *not a wasted effort* on the part of the public, thus avoiding the dangerous misconception that it was another 'science failure'.
Erik, I always see your blog and comment here... and I want to Inform you all the mess that there's here in Chile
I was Camping when the earthquake happened, when it stopped i called my parents and told them i was ok and that i had talked with some friends from far cities from me, and they felt it.... so it was really big!
I study Geology and When i felt the earthquake i knew there was a Tsunami Alert and all the troubles it will cause, so i called all the ppl i could and told'em RUN TO THE MOUNTAIN FOR SECURITY.
I was in the mountain near a lake, even the lake had a Tsunami and the water level is 60 cms less
This earthquake is CATASTROPHIC, I study in CONCEPCION, and was supposted i was going to star classes this 15th, now The city is a Jungle, People steals, kill , theres no light, water, gas, food. I dont know about my friends, and my apartment.
Afortunately I am with my family, but the situation of the Country is a mess.
Well i can write much more, but i have electricity and internet problems
The country will stand up!!! :)
Thanks for the update, Manuel. It is good to point out that although Chile did weather this larger earthquake much better than Haiti, it doesn't mean that there wasn't widespread devastation to the country. Don't forget that when it comes to supporting Chile and its recovery.
I am all for warnings being given for any possibility of widespread death and destruction. What were they supposed to do...ignore it until they actually saw the Tsunami? I think a lot of scientists are afraid to be the first to say anything when they see a threat, they don't want to look bad if the event doesn't materialize. I think the guys that made the call on the Tsunami did the only thing they could do and still be able to sleep at night.
Jon Stewart says it all:
http://www.thedailyshow.com/ check "the uninformant"
The papers report the same as Manuel, the city of Conception "is a jungle" so although the damage done by the quake is unimaginable, in the final analysis it may be that the greatest damage done will prove to be the one by humans. As if the natural disaster wasn't enough! :(
question for the community. Does it appear that the great quakes along the Nazca subduction zone are trending towards the north? If so, then the next big stress relief event might be much closer to Santiago, some number of decades from now.
Very nice Sakurajima movie! It's a pity Mt Pinatubo
didn't wait 19 more years. The media coverage is so
much better now :)
Scientists say tsunami models should be tested.
-The South American coast has few monitoring points than does the US Coast, particularly in the north, near Alaska.
- 'Had he been asked a week ago whether a magnitude 8.8 earthquake in Chile would cause a destructive tsunami in Hawaii, "I would have said, 'Unquestionably. It's going to be a bad scene,"' (Gerard Fryer, a geophysicist at the Pacific Tsunami Warning Center in Hawaii, former faculty UH)
- Two models in use at the NOAA Pacific Ocean Tsunami Center (http://nctr.pmel.noaa.gov/) underestimated wave strength. While the models over-estimated wave strength and dwell interval, scientists point to model data inputs error in estimated quake and overlying coastal waters depth, approx 100 km from shore.
- Modeling wave energy dissipation is computationally expensive and therefore, ignored at present. Modeling wave interval period is difficult if the model inputs are incorrect.
Pacific Ocean 'like a shaken bath', says tsunami expert.
AAP, 28February 28
Other national tsunami warning centers were also very cautious in their issues warnings for coastal seas and 'built' environments.
'Mr Hainsworth (scientist at JATWC) said Australia's distance from Chile would not matter when tsunami conditions arrived. "We're not expecting to see significant areas of land inundated (but) it could happen locally because of the shape of a bay or estuary or headland," he said.'
Australian Tsunami Warning System.
Australian Gov't/Geosciences Australia, tsunami model can be found by searching for the following web page:
ANUGA - hydrodynamic inundation modelling
The JATWC used estimated wave arrival times and descriptions of recreation/boating and 'rubbernecking' risks, avoiding wave height estimates in the series of warnings issues following the Chile 8.8 earthquake.
I live on the Gold Coast in Queensland Australia. We heard a tsunami warning that the tsunami would arrive around 815 a.m. By 930 nothing had happened so like a lot of other people around here I figured it was all over and went surfing. At about 1030 while out in the water I noticed a sudden surge in current activity which I later learned was the remains of the tsunami - the prediction of arrival time had been way off due to the effect of the outgoing tide which slowed it down. In the future I hope the predictions are more accurate.
The outgoing tide wouldn't have delayed tsunami waves, but it would have changed shallow water depth and hence available water mass along coastal shelves, harbors and bays. Guessing that you may not have been aware of the initial wave due to tidal effects and saw the second, larger wave arrive, instead.
I briefly considered (a) earth-moon distance (b) spring tide and (c) full moon effects, all present at the end of February. However, models would account for these effects.
Energy dissipation over distance must have been a factor, perhaps caused by poor early energy propagation that could not be sustained over distance. Large, short-lived tsunami waves are reported to have wiped out small coastal villages in Chile; there would have been little time for residents to respond to warnings. Buildings in these small coastal towns were not built to withstand major wave inundation. Photos posted on the net showed beached larger wooden fishing vessels and piled vehicles against apartment buildings, indicators of local tsunami wave energy.
Many tsunami models are rather new; we presume they are still undergoing factor adjustments (or learning-algorithm refinement) as event history catalog grows since model inception.
Question: Did this quake make the recurrence of
http//en.wikipedia.org/wiki/1868_Arica_earthquake more or less likely, more or less destructive, or did the seismic gap mentioned in the article vanish in Southern Peru earthquake in 2000s? Imho, a thing to look into.
@Passerby: Coastal areas are not necessarily well mapped and no satellite instrument I know of can measure the depth of the water - no, you do the mapping by a variety of techniques including towing sonar fish. For deeper water some areas have been mapped by submarines using their sonar. The vast majority of the oceans remains unmapped though. As for deep sea gauges, there really aren't all that many of them considering the size of the ocean and such remote gauges tend to report fairly sparsely since they tend to use a public and generally very low bandwith channel on certain satellites (so communication is essentially free for the user).
The CALIPSO instrument may be able to map very shallow waters if the atmospheric conditions are good, but the coverage is not sufficient to provide good topographical maps.
At any rate, unless the models have a long history of being correct, the best thing to do is move away if there is a possibility of a tsunami. Very frequently there is barely a rise in the water level, but you sure don't want to be there if you get a big wave. It may be possible to refine these models using empirical data rather than through more detailed topography - but that would take many decades since the vast majority of quakes do not cause a noticeable tsunami. As for the "need more sensors, need better topography" - that may very well be something in the "not practical" box. Climate predictors always claim they need more of this and that data (and that if they only had more good data they'd get better results - a claim I simply do not believe) but it's such a huge task to raise the money for any large instrumentation project.
A potential confounding factor in forecasting estimated water depth over the EQ epicenter is proximity to the Chile-Peru Trench, 165km off the coast.
See: Wikipedia, Peru-Chile Trench
Example of a bathymetric map resource, Chile (one of many bath map repositories with archived bath maps holdings, offshore South America/Chile and Argentina_)
See: USGS CMG InfoBank Atlas, Chile bathymetry
Number of tsunami events per year.
'During the 101-year period from 1900 to 2001, 796 tsunamis were observed or recorded in the Pacific Ocean according to the Tsunami Laboratory in Novosibirsk. 117 caused casualties and damage most near the source only; at least nine caused widespread destruction throughout the Pacific. The greatest number of tsunamis during any 1 year was 19 in 1938, but all were minor and caused no damage. There was no single year of the period that was free of tsunamis.
The distribution of tsunami generation is as follows: 17% of the total tsunamis were generated in or near Japan, South America, 15%: New Guinea Solomon Islands, 13%; Indonesia, 11%; Kuril Islands and Kamchatka, 10%; Mexico and Central America, 10%; Philippines, 9%; New Zealand and Tonga, 7%; Alaska and West Coasts of Canada and the United States, 7%; and Hawaii, 3%.'
Searchable on-line tsunami database, 2000-2008.
NOAA/WDC Tsunami Event Database
A casual Google check, using the search term 'Seismic Imaging and Bathymetry of The Central Chile Margin', yields a useful list of recent and relevant publications.
We've been speculating about some possible volcanic activity following the great Chile earthquake, but now it seems the action is returning to Iceland.
There is something serious happening under Icelandâs EyjafjallajÃ¶kull, a small, glacier-covered volcano immedately to the west of Katla volcano. I donât know enough Icelandic to understand what the following newspaper bit says, but it contains words like âgosiÃ°â, which means âvolcanic eruptionâ, not referring only to the most recent eruption of this volcano, in 1821-1823.
Plus, the Icelandic Meteorological Officeâs seismicity map shows intense seismic activity in the area of the volcano:
Boris I also found this:
I also found this:
Magma ascent at coupled volcanoes: Episodic magma injection at Katla and EyjafjallajÃ¶kull ice-covered volcanoes in Iceland and the onset of a new unrest episode in 2009
Katla and EyjafjallajÃ¶kull "are coupled"?
@Boris, thanks for those links. They are having some serious activity. Seems that they are having several swarms that go from one area to another. I don't know enough about Iceland to know if they are connected (my guess is they could be just because the way the island is)or not, but it is interesting to follow.
I noticed, too, that Brevard College is planning their Iceland tour which is a camping and hiking tour and it lasts for about two weeks or so. Wish I was 20 again so I could go. I would love to do that, but out of the question. Some of you who can may be interested in it as you can get college credits for going.
I have seen some of the damage the tsunami did to Chile and I really feel for those people. They are having to arm themselves against looters and are having a real problem with that. Let's think good thoughts towards the people who have to deal with the all the difficulties and are doing the best they can.
Did I misunderstand something or are Katla and EyjafjallajÃ¶kull part of an approximately 10-km wide and 700 m deep caldera under the MyrdalsjÃ¶kull ice cap?
First, comment on a slightly misguided viewpoint on earthquake engineering, building codes and building materials written by DB Marron, finance professional and visiting professor, Georgetown U Public Policy Institute, published in the Christian Science Monitor.
The Chilean earthquake, at 8.8, is an example of the upper bounds of earthquake engineering protection capacity. Mr Marron's observation that building material quality is just as likely to be a factor as building code enforcement in the relatively low loss of life and urban damage, is valid.
A quick Google check reveals that, not surprisingly, Chile's population has more than doubled since the 1960 earthquake (following global population trends). There has also been rapid growth in Chilean urban centers as more people have moved to cities seeking employment and better living conditions with increasing national wealth since the mid-1980s that saw Chile substantially outperforming it's continental neighbors in economic development.
Strong economic expansion, mostly in natural resources exports, fueled an upward trend in GDP through 1999, with a slightly reduced growth rate in recent years, driving infrastructure development - mostly in urban centers - and accentuating a growing gap in wealth between rich and poor, and ethnic/cultural divisions in income and social supports.
Most of the nearly 800 deaths reported to date occurred in economically disadvantaged communities with substandard housing and Federal investment. The majority of damage was reported for older homes built before building code adoption, but more frequently, newer homes not built 'to code', of cheap materials, perhaps not due to corruption as the difficulty in broadly supplying and administering governmental services and oversight across a diverse economic and cultural spectrum of communities.
Mr Marron can bet that the global civil/structural, mechanical and geotechnical engineering community will be studying the effects of this earthquake on the Built Environment in Chile for lessons learnt. But there is also a strong likelihood that the power and communications engineering disciplines will also be peering at the aftermath, because there also important lessons on communication and power grid structures base that must be addressed in the rebuilding effort.
Boris: the Google translation points to elevated seismic activity associated with minor clustered tremors and not 'volcanic noise', perhaps associated with glacier movement. A similar activity pattern was evaluated at Katla and determined to be glacier-related, in a study published last year.
It is interesting to follow the Iceland earthquake activity. There has been a lot of small earthquakes under EyjafjallajÃ¶kull during the past weeks. As I understand it EyjafjallajÃ¶kull and Katla might have a coupling. According to Swedish wikipedia it was noticed that during the most recent eruptions of EyjafjallajÃ¶kull 1612 and 1821-1823, Katla erupted simultaneously (1612 and 1823). Well, almost at least.... According to Global volcanism program EyjafjallajÃ¶kull stopped erupting 1 jan 1823 and Katla started erupting June 26, 1823.
I'm looking forward to the papers that will posted on this topic, on the Volcanism blog tomorrow.
I found the webpage of a postdoc (Elske de Zeeuw-van Dalfsen) who had studied the EyjafjallajÃ¶kull volcano seismic swarm and uplift data from the 90s at this volcano (also data gathered from Katla), read through several of her references. Several studies suggest magma intrusion as a plausible explanation, but with reservations due to seismic signal migration southward and differing centroids for seismic signal and GPS uplift horizontal component.
DEFORMATION DUE TO MAGMA MOVEMENT AND ICE UNLOADING AT KATLA
VOLCANO, ICELAND, DETECTED BY PERSISTENT SCATTERER INSAR. (2007).
"We use both persistent scatterer and combined multi-
ple acquisition InSAR techniques to analyse ENVISAT
ASAR data acquired from September 2003 to July 2006,
and ERS data acquired between 1995 and 2003, to deter-
mine line-of-sight displacements for the area surrounding
Katla. The signal we see is consistent with a response to
ice unloading, and intrusion of magma or fluids is not re-
quired to explain the data. We donât, however, rule out
shallow intrusion beneath the caldera causing local de-
formation that is not visible on the volcano flanks. We
also identify possible local landsliding occurring on the
A 2009 abstract (Earthquakes and Pre-Earthquake Processes
Conference, OrkugarÃ°ur, ReykjavÃk, October 2009) discusses these seismic episodes in terms of periodic E-W trending, 'pipe-like feeder channel' magmetic intrusion events.
See: INTERPRETING SEISMIC SIGNALS FROM ICELANDIC VOLCANOES.
KristÃn S. VogfjÃ¶rÃ°, Sigurlaug HjaltadÃ³ttir, Einar Kjartansson, Matthew J. Roberts, and Ragnar Slunga.
speaking of glaciers and ice, I recall reading long ago that increased volcanism on Mt. Garibaldi (in B.C.) is associated with withdrawal of ice cover as the end of several ice ages. The implication being that reducing the mass on top of the volcano allowed it to erupt more easily and/or frequently. I'm not sure if this agrees with current theories, but it does make me curious about the effect that the current rapid retreat of glaciers on Mt. Rainier might have on its future behavior. But at least I was able to climb Mt. Rainier a couple of times in my distant youth, something that I am still kicking myself for not doing with Mt. St. Helens while it still had its symetrical summit.
Ice & Volcanoes. While there are a few interestingly deformed volcanoes born under ice such as Hoodoo Mtn and on Iceland, what would happen underneath a really thick cover such as those that occured during the Ice Ages? How large would an eruption have to be if it was to break through an ice cover ~1Â½ km thick? How would a really large eruption (VEI 6 or 7) "fare"? Are there any places on Earth where such a site has been exposed by the retreating ice?
Nice views into Kilauea Pit this am.. The lava surface fairly active with low level fountaining. Worth a look..
I found some information on the recent activity that I tryed to translate online. http://www.visir.is/article/20100304/FRETTIR01/578489653
The translator did not succes in translating all words, but it resulted in the following:
The minnstakosti six earthquakes urÃ°u under EyjafjallajÃ¶kull night, but all three on the Richter. Significantly has been smÃ¡skjÃ¡lfta on these grounds recently, but jarÃ°vÃsindamenn consider it not be gosÃ³rÃ³a, though jarÃ°skorpan seems to be something that Ã¾enjast. Source earthquake are all down to a depth of ten kilometers.
When I did linguistics for my MA, we did some Olde English and I've since had a bit of ditto Swedish, so I can make an (educated?) guess at a few of the words, Mattias:
"Smaskjalfta" = smÃ¥skalv = small quakes, "jarÃ°vÃsindamenn" ~Earth wisdom men = geophysisicists?, "jarÃ°skorpan" = jordskorpan = the (Earth's) crust, "Ã¾enjast" = tÃ¤njs = is stretched.
For future reference, it might be useful to know that "Ã°" is pronounced the same way as "th" in "this", whereas "Ã¾" is the "th" of thin. In Olde English, "EorÃ°an" was the name for the world and it is easy to see how this has developed into the modern Earth of English), jarÃ° of Icelandic & Jorden in Swedish.