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andy_t_roo

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Re: Earthquakes and climate change
« Reply #50 on: May 09, 2015, 12:54:45 AM »
One problem with earthquakes is that stress continually builds up until released. When the pressure is close to release, even a small cause can trigger the inevitable.

Perhaps a week or month, or year sooner than the pressure build up would of done anyway.

AbruptSLR

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Re: Earthquakes and climate change
« Reply #51 on: May 09, 2015, 05:15:52 AM »
For those who are wondering whether the water from a 2m SLR by 2091 would be uniformly distributed around the world and its tectonic plates, then you can mentally combine the image in panel (d) for RCP 8.5 from AR5 together with an additional meter of water height from the WAIS distributed according to the fingerprint effect shown in the second attached image.  Clearly, such a water distribution would apply non-uniform stress on different tectonic plates (thus promoting additional future seismic activity).  Also, note that as most of the land surface would not be gaining mass due to such SLR (and in glacial areas would be losing mass); there would be additional differential stress on the tectonic plate margins due to this mass imbalance as well.
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Laurent

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Re: Earthquakes and climate change
« Reply #52 on: May 09, 2015, 11:48:30 AM »
The Nepal earthquake made Mount Everest a tiny bit shorter
http://i100.independent.co.uk/article/the-nepal-earthquake-made-mount-everest-a-tiny-bit-shorter--xy8QUlPceW

Climate may influence earthquakes (eventually) but earthquake certainly have an effect on climate. The checking of the himalaya glaciers should not be so good for their stability...?

Himalayan 'drop after Nepal quake'
http://www.bbc.com/news/science-environment-32625431
« Last Edit: May 09, 2015, 12:05:21 PM by Laurent »

AbruptSLR

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Re: Earthquakes and climate change
« Reply #53 on: May 09, 2015, 02:33:52 PM »
As a follow-up to my Replies #44, #46 & #48, while the GRACE image in Reply #44 shows that Eastern portions of the Himalayas have recently (2003-2010) been receiving more than normal snowfall; the following peer reviewed reference indicates that the Western and Central portion of the Tibetan Plateau glaciers have been starved of recent snowfall to the extent the two studied glaciers have sustained annual ice loss rates of more than several hundred millimeters of water equivalent since at least the 1980's (see the two associated images).  Also, we know that worldwide mean surface temperature increases are occurring faster at high mountain elevations, and the Himalayas are no exception.  Therefore, I expect ice mass loss from the Western & Central Tibetan Plateau to accelerate in the coming decades, and the associated mass loss could change local tectonic plate stresses sufficient to trigger more frequent seismic events in this area in this timeframe.

Kang, S. C., Wang, F. Y., Morgenstern, U., Zhang, Y. L., Grigholm, B., Kaspari, S., Schwikowski, M., Ren, J. W., Yao, T. D., Qin, D. H., and Mayewski, P. A.: Decapitation of high-altitude glaciers on the Tibetan Plateau revealed by ice core tritium and mercury records, The Cryosphere Discuss., 9, 417-440, doi:10.5194/tcd-9-417-2015, 2015.


http://www.the-cryosphere-discuss.net/9/417/2015/tcd-9-417-2015.html

http://www.the-cryosphere-discuss.net/9/417/2015/tcd-9-417-2015-print.pdf


Abstract: "Two ice cores were retrieved from high elevations (~ 5800 m a.s.l.) at Mt. Nyainqentanglha and Mt. Geladaindong in the southern to inland Tibetan Plateau. The combined analysis of tritium (3H), 210Pb, mercury tracers, along with other chemical records, revealed that the two coring sites had not received net ice accumulation since at least the 1950s and 1980s, respectively, implying an annual ice loss rate of more than several hundred millimeter water equivalent over these periods. Both mass balance modeling at the sites and in situ data from nearby glaciers confirmed a continuously negative mass balance (or mass loss) in the region due to the dramatic warming in the last decades. Along with a recent report on Naimona'nyi Glacier in the Himalaya, the findings suggest that glacier decapitation (i.e., the loss of the accumulation zone) is a wide-spread phenomenon from the southern to inland Tibetan Plateau even at the summit regions. This raises concerns over the rapid rate of glacier ice loss and associated changes in surface glacier runoff, water availability, and sea levels."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Timothy Astin

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Re: Earthquakes and climate change
« Reply #54 on: May 09, 2015, 05:51:21 PM »
Therefore, I expect ice mass loss from the Western & Central Tibetan Plateau to accelerate in the coming decades, and the associated mass loss could change local tectonic plate stresses sufficient to trigger more frequent seismic events in this area in this timeframe.


ASLR provides lots of interesting links about changes in vertical loading which are expected to accelerate. However, in judging their importance for changes to seismicity, there needs to be a quantitative consideration of these loading/unloading effects on vertical stress, how these compare to changes in horizontal stress from plate tectonics, and hence what controls differential stress change on potential fault planes at depth.

The GRACE mass changes quoted by ASLR are a few cm of snow.

The lnk provided by Laurent #52 to the BBC report of vertical changes in elevation following the Nepal earthquake. Almost instantaneous changes in elevation are of the order of 1m to 1.5 m  These elevation changes are two orders of magnitude greater than the unloading effects from ice/snow loss over the last 10 years. These elevation changes are linked to the instantaneous variation in horizontal crustal stresses resulting from the fault plane slip, whcih have orders of magnitude greater variation than changes in vertial stresses through unloading.

Therefore it is the cyclical variation in horizontal stresses resulting from plate tectonic motion which determines the destructive earthquake behaviour in the Nepal region.

I think it is clear that quantiitative considerations show that man-made climatic change is not the dominant factor controlling frequency of occurrence of destructuve seismicity in the Himalayas.


Of course, expected significant changes, consequent on anthropogenic global warming, to Himalayan glaciers and resulting river hydrology have other, potentially very significant detrimental consequences for people living in south and central Asia.




AbruptSLR

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Re: Earthquakes and climate change
« Reply #55 on: May 09, 2015, 06:38:49 PM »
I think it is clear that quantiitative considerations show that man-made climatic change is not the dominant factor controlling frequency of occurrence of destructuve seismicity in the Himalayas.

Tim,
I imagine that folke_kelm must be pre-occupied doing something else today; otherwise, with his love of logical rigor I am sure that he (she?) would point-out the numerous portions of your reply that are logical red-herrings.

First, no one that I am aware of in this thread (certainly not myself) have claimed that the influence of climate change dominates tectonic activity, with regard to the Nepal earthquake or anywhere else in the world.  The influence of climate change can be viewed as a possible stress riser added on-top of the otherwise dominant tectonic forces (any other thought is ludicrous and would only be thought by individuals with a poor understanding of science), that indeed vary from site to site and on the local tectonic history and boundary conditions.  In this light, anthropogenic forcing (such as Indian groundwater mining, in Northwest India, to compensate for low rainfall and high population growth) can act as a trigger to increase the frequency and/or magnitude of seismic activity dominated by tectonic forces.  Thus it is a "straw-man" to say that because the influence of anthropogenic forcing does not dominate seismic response that the influence of anthropogenic forcing will not have a systematically growing impact (which will be different in different locations) on seismic activity this century, with continued anthropogenic forcing.

Second, while I am not qualified to run a seismic hind-caste of the Nepal earthquake to determine what influence the mass changes on all sides of Nepal from:

(a) the Northwest Indian groundwater mass shown in the white box of the first attached image; which, resulted in the over 20 cm change in equivalent water height from 2003 to 2012 shown in the second attached image; and which, amounts to a loss of hundreds of gigatonnes of cumulative water mass (over these years) as indicated by the previously posted third attached image.  See the Chen et al 2014 reference at the end of this post.
(b) the accumulation of snowfall in the Eastern Himalayas (shown by the GRACE image in Reply #44), and
(c) the loss of glacial ice in the Western & Central Tibetan Plateau cited by Kang et al 2015 in Reply #53.

… I am confident that their cumulative influence (plus what happened from 2012 to 2015) is not negligible.

Finally, you should not compare the elevation changes of portions of the Himalayas (cited by Laurent) after the Nepal event to the different equivalent water height changes in groundwater, snow and glacial ice; as this is comparing apples to oranges.

Chen, J.L., J. Li, Z.Z. Zhang, S.N. Ni, Long-Term Groundwater Variations in Northwest India From Satellite Gravity Measurements, Global and Planetary Change, Vol. 116, 130-138, doi: 10.1016/j.gloplacha.2014.02.007, 2014.

ftp://ftp.csr.utexas.edu/pub/ggfc/papers/2014GPC_NWI_Groundwater.pdf
ASLR
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Timothy Astin

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Re: Earthquakes and climate change
« Reply #56 on: May 10, 2015, 02:42:30 AM »

First, no one that I am aware of in this thread (certainly not myself) have claimed that the influence of climate change dominates tectonic activity, with regard to the Nepal earthquake or anywhere else in the world.  The influence of climate change can be viewed as a possible stress riser added on-top of the otherwise dominant tectonic forces.


I am glad we agree that tectonic activity is the dominant control on frequency and magnitude of earthquakes globally.  I use the example of the recent Nepal earthquake to show that the "stress riser" from climate changes referred to is insignificant for magnitude and frequency of large earthquakes in this part of the world.

I also agree with previous posts that where there is localised, rapid, very large-scale unloading from disintegration of ice-sheets, then local seismic activity will normally increase.


Finally, you should not compare the elevation changes of portions of the Himalayas (cited by Laurent) after the Nepal event to the different equivalent water height changes in groundwater, snow and glacial ice; as this is comparing apples to oranges.



One common property of apples and oranges is that they both transmit a vertical stress to the surface they are sitting on in proportion to their mass.

It is entirely fair to compare the vertical stress resulting from 1m of rock of density approx 2600 kg.m-3,  with that of 3 cm of ice/water of density approx. 1000 kg.m-3., or with 20cm of groundwater in rocks of average porosity of, say, 15% also with density of approx 1000 kg.m-3.  Vertical stress changes from the loss of groundwater or of ice/snow over 10 to 20 years is roughly two orders of magnitude smaller than the instantaneous vertical stress change revealed by the topographic change caused by the earthquake.

(And for simplicity sake, I had not explored the linkage between the observed change in vertical stress above the fault plane and the inferred change in horizontal stress below the fault plane.  Because of the resolution of forces across the fault plane, the change in horizontal stress associated with the earthquake is much larger than the resulting change in vertical stress observed above the fault plane.)








AbruptSLR

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Re: Earthquakes and climate change
« Reply #57 on: May 10, 2015, 02:56:13 PM »
Tim,

The points that you make about the dominance of tectonic forces have no more meaning than saying that climate still dominates climate change.  The Earth does not care what climatic, or tectonic, state that it is in; it is modern human society that is poorly prepared to deal both with change to the climate and to changes in the magnitude and frequency of seismic activity triggered by anthropogenic forcing.

The Nepal earthquake was the largest modern history; which may, or may not, be a coincidence; and which may, or may not, be due to the fact that the hundreds of gigatonnes of anthropogenically changed water mass distribution around Nepal helped to release more of the "dominate" tectonic force than would have been released without the anthropogenic intervention.  The fact that structures in Nepal that had withstood hundreds of years of past seismic events, but which failed in the recent event, raises the question of where all of the design criteria for mankind's infrastructure needs to be increased in order to account for the influence of anthropogenic forcing increasing the "design event" associated with a given return period (whether due to increased frequency/magnitude of weather events or increased frequency/magnitude of seismic events).  While it is true that seismic events build-up tectonic energy gradually; which can be reduced by any given event; nevertheless, there is already so much seismic energy already built-up in the tectonic plate system; that climate change could trigger a temporarily accelerated frequency/magnitude of seismic events for hundreds of years before any new equilibrium condition could be established

Charles Darwin once said: "It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change."  Furthermore, the Bible points out that: "Blessed are the meek: for they shall inherit the earth."  In light of such received wisdom, it seems to me that society would do well to stop focusing on the "dominance" of climate compared to current climate change, or the "dominance" of tectonic force compared to associated anthropogenic forcing; and instead focus on how poorly prepared its own systems (economic, technological, institutional, governmental, etc) are for address all of the numerous "stress risers" associated with anthropogenic forcing, including the accelerating pace of changes to the frequency/magnitude of tectonic activity associate with anthropogenic activity.

ASLR
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Earthquakes and climate change
« Reply #58 on: May 10, 2015, 04:48:45 PM »
The linked article discussing the case that fracking maybe causing swarms of small earthquakes in Texas (see the extract below).  This thread cites numerous other cases associating swarms of small earthquakes in North America associated with fracking, and it should be noted that fracking operations are still ramping-up in many other areas of the world (North America just had a head start on the rest of the world).

Many people will think: "What's the problem with swarms of small earthquakes?  People are adaptable, and having the locals suffer such small earthquakes is a small price to pay for the market (and me) to gain access to these valuable fossil fuels."  Unfortunately, besides the accelerated groundwater contamination and the GHG emissions; such swarms of such small local earthquakes can accumulate tectonic stresses in the rock of adjoining areas.  Therefore, as fracking operations spread around the world, tectonic stresses will be accumulated in the rock of adjoining areas at multiple locations around the world.  Therefore in the future, large earthquakes (dominated by natural tectonic action) may likely trigger moderate sized aftershocks in these adjoining areas with accumulated tectonic stresses, which may be large enough to cause structural damage and loss of life.
 
Furthermore, in the future climate change associated damage may have overtaxed to insurance industry to the point that it makes earthquake insurance premiums so high that they are unaffordable to the general public, and if so the public may need face the consequences of future seismic damage will much less societal assistance then they are currently used to believing that they are entitled to.  Also, I note that when the international insurance industry gets over-stresses they pass of higher premiums to everyone in the modern society, including to people living far away from places subjected to high risks (whether from more frequent strong earthquakes, or more frequent flooding, etc.).

http://edition.cnn.com/2015/05/09/us/texas-earthquakes-fracking-studies/

Extract: "What do scientists say?
The problem isn't solely the drilling, some scientists argue. It's the disposal of a wastewater byproduct of the drilling.
The way most companies dispose of this byproduct is to push it thousands of feet underground. The mixture of millions of gallons of water and potentially harmful chemicals are pumped into the earth's crust, and the liquid lubricates the faults, causing the earth to shake, or so the theory goes.
A key point in SMU's preliminary report is about the depth of these earthquakes, which have been 3 to 4 miles deep. This places most of them "in the shallow crystalline basement (granites) below the sedimentary rocks (sandstone, shale, limestone, etc.) that comprise the Fort Worth Basin."
An injection of wastewater that reaches the granite basement can agitate an existing -- or previously unknown -- branch of a large fault, resulting in the ground shaking."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Tor Bejnar

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Re: Earthquakes and climate change
« Reply #59 on: May 11, 2015, 03:16:21 PM »
Steve Drury's Earth Pages has an article on Earthquake hazard news that focuses on petroleum industry fluid injection wells. 
The main worry is that waste water disposal might trigger movements with magnitudes up to 7.0: in 2011 a magnitude 5.6 earthquake hit a town in oil-producing Oklahoma and damaged many buildings.
The article ends with
None of these areas are likely to experience the horrors of the 25 April 2015 magnitude 7.8 earthquake in Nepal. However, it also occurred in an area expected to be relatively stable compared with the rest of the Himalayan region. The only previous major tremor there was recorded in the 14th century. This supposedly ‘low-risk’ area overlies a zone in which small tremors or microearthquakes occur all the time. Such zones – and this one extends along much of the length of the Himalaya – seem to mark where fault depths are large enough for displacements to take place continually by plastic flow, thereby relieving stresses. Most of the large earthquakes have taken place south of the microseismic zone where the shallow parts of the Indian plate are brittle and have become locked. The recent event is raising concerns that it is a precursor of further large earthquakes in Nepal. Its capital Kathmandu is especially susceptible as it is partly founded on lake sediments that easily liquefy.

In general there might be a connection between ground water depletion and a region becoming less 'plastic' (allowing for fewer but larger earthquakes).  I don't think this happened in Nepal though:  groundwater depletion happens in the upper 1 or 2 kilometers of the crust whereas the decreased plasticity (if that is what happened in Nepal last month) happened about 15 km down.

(Oklahoman earthquakes tend to be around 3-5 km deep, as are the waste water injection wells.)
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AbruptSLR

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Re: Earthquakes and climate change
« Reply #60 on: May 11, 2015, 04:47:14 PM »
Steve Drury's Earth Pages has an article on Earthquake hazard news that focuses on petroleum industry fluid injection wells. 
The main worry is that waste water disposal might trigger movements with magnitudes up to 7.0: in 2011 a magnitude 5.6 earthquake hit a town in oil-producing Oklahoma and damaged many buildings.
The article ends with
None of these areas are likely to experience the horrors of the 25 April 2015 magnitude 7.8 earthquake in Nepal. However, it also occurred in an area expected to be relatively stable compared with the rest of the Himalayan region. The only previous major tremor there was recorded in the 14th century. This supposedly ‘low-risk’ area overlies a zone in which small tremors or microearthquakes occur all the time. Such zones – and this one extends along much of the length of the Himalaya – seem to mark where fault depths are large enough for displacements to take place continually by plastic flow, thereby relieving stresses. Most of the large earthquakes have taken place south of the microseismic zone where the shallow parts of the Indian plate are brittle and have become locked. The recent event is raising concerns that it is a precursor of further large earthquakes in Nepal. Its capital Kathmandu is especially susceptible as it is partly founded on lake sediments that easily liquefy.

In general there might be a connection between ground water depletion and a region becoming less 'plastic' (allowing for fewer but larger earthquakes).  I don't think this happened in Nepal though:  groundwater depletion happens in the upper 1 or 2 kilometers of the crust whereas the decreased plasticity (if that is what happened in Nepal last month) happened about 15 km down.

(Oklahoman earthquakes tend to be around 3-5 km deep, as are the waste water injection wells.)


I note that lower plasticity can also be a function of higher rate of loading; and as the change in groundwater elevation in Northwest India was not directly above Nepal's 2015 epicenter; it makes much more sense to talk about the rapid change in hundreds of gigatonnes of water weight on the Indian tectonic plate rapidly changing the stress in the fault beneath Nepal rather than talking about changes in groundwater at the fault (which likely did not happen).

“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Earthquakes and climate change
« Reply #61 on: May 11, 2015, 06:00:54 PM »
To state the obvious, most scientists have become highly specialized in our current reality; but with regard to the possible impacts of climate change on tectonic activity, there currently is no entity that I am aware of that takes responsibility to integrate all of the various risks associated with different mechanisms into an integrated whole synergistic projection; in a similar manner as GCMs or ESMs do for oceanic, atmospheric and other associated Earth Systems.  This leaves the risks associated with anthropogenic changes to this tectonic activity relatively poorly evaluated.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Earthquakes and climate change
« Reply #62 on: May 11, 2015, 06:33:25 PM »
I thought that I would re-post the following abstract (from the Antarctic Folder); which indicates that after GIA correction the Amundsen Sea sector is probably contributing more (up to 40% more) to SLR than previously projected.  This emphasizes both the importance, and uncertainties associated with the Glacial Isostatic Adjustment (GIA); which, can have a significant impact on both associated SLR and associated seismic activity projections:

An investigation of Glacial Isostatic Adjustment over the Amundsen Sea sector, West Antarctica
by: A. Groh; H. Ewert, M. Scheinert, M. Fritsche, A. Rülke, A. Richter, R. Rosenau, R. Dietrich
http://dx.doi.org/10.1016/j.gloplacha.2012.08.001

Abstract
The present study focuses on the Amundsen Sea sector which is the most dynamical region of the Antarctic Ice Sheet (AIS). Based on basin estimates of mass changes observed by the Gravity Recovery and Climate Experiment (GRACE) and volume changes observed by the Ice, Cloud and Land Elevation Satellite (ICESat), the mean mass change induced by Glacial Isostatic Adjustment (GIA) is derived. This mean GIA-induced mass change is found to be 34.1 ± 11.9 Gt/yr, which is significantly larger than the predictions of current GIA models. We show that the corresponding mean elevation change of 23.3 ± 7.7 mm/yr in the Amundsen Sea sector is in good agreement with the uplift rates obtained from observations at three GPS sites. Utilising ICESat observations, the observed uplift rates were corrected for elastic deformations due to present-day ice-mass changes. Based on the GRACE-derived mass change estimate and the inferred GIA correction, we inferred a present-day ice-mass loss of − 98.9 ± 13.7 Gt/yr for the Amundsen Sea sector. This is equivalent to a global eustatic sea-level rise of 0.27 ± 0.04 mm/yr. Compared to the results relying on GIA model predictions, this corresponds to an increase of the ice-mass loss or sea-level rise, respectively, of about 40%.

The first accompanying figure shows an overview of the Amundsen Sea sector, West Antarctica. The red line defines the generalised drainage basins of Pine Island Glacier, Thwaites Glacier and Smith Glacier (PITS). Locations of three GPS campaign sites are marked by red triangles.

The second figures shows the GRACE data from 2003 to 2009 which the papers says needs to be corrected to indicate about 40% more ice mass loss than previously reported
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Earthquakes and climate change
« Reply #63 on: May 11, 2015, 06:45:39 PM »
For those who are not clear about the implications of the information that I posted in Reply #62, the GRACE satellite only measure mass change, so if ice mass is leaving the Amundsen Sea Embayment, ASE, but magma is flowing back-in underneath the lithosphere, then the uncorrected GRACE measurements may be underestimating the true amount of ice mass loss.  Unfortunately, it is not well understood how quickly the magma is flowing back underneath the ASE, so there currently is a monitoring effort going on to try to reduce the uncertainties associated with this mechanism.  If a lot of magma is flowing in to the ASE area, then not only are the current SLR projections erring on the side of least drama, but so to are the current seismicity projections for this ASE area.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Laurent

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Re: Earthquakes and climate change
« Reply #64 on: May 11, 2015, 08:21:55 PM »
That flow of magma should be measurable by sismic devices ? Do we know the records of these devices in the area ?
I have heard that some scientists in Yellow stone use a special technic to assess the flow of magma...may be that can help us to assess what is going in Antarctic ?

AbruptSLR

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Re: Earthquakes and climate change
« Reply #65 on: May 11, 2015, 08:33:45 PM »
That flow of magma should be measurable by sismic devices ? Do we know the records of these devices in the area ?
I have heard that some scientists in Yellow stone use a special technic to assess the flow of magma...may be that can help us to assess what is going in Antarctic ?


Laurent,

The is a lot more information on the topic you ask about in the Antarctic Tectonics thread; however, I re-post the following as one of my more recent posts on this topic:

Re-post: "The following abstract comes from the International Glacial Society Proceeding 65 at the following link:

http://www.igsoc.org/symposia/2014/chamonix/proceedings/procsfiles/procabstracts_65.htm

It is particularly interesting that Wilson et al 2014 indicate that the magma beneath Marie Byrd Land has very low viscosity:

70A1149
The POLENET-ANET integrated GPS and seismology approach to understanding glacial isostatic adjustment and ice mass change in Antarctica

Terry WILSON, Michael BEVIS, Stephanie KONFAL, Richard ASTER, Julien CHAPUT, David HEESZEL, Douglas WIENS, Sridhar ANANDAKRISHNAN, Ian DALZIEL, Audrey HUERTA, Eric KENDRICK
Corresponding author: Terry Wilson
Corresponding author e-mail: wilson.43@osu.edu

Abstract: "The POLENET-ANET project is simultaneously resolving crustal motions, measured by GPS, and Earth structure and rheological properties, mapped by seismology. Measured vertical and horizontal crustal motion patterns are not explained by extant glacial isostatic adjustment (GIA) models. These models have ice histories dominated by ice loss following the Last Glacial Maximum (LGM) and rely on 1-D Earth models, with rheological properties varying only radially. Seismological results from POLENET-ANET are revealing significant complexity in lateral variation in Earth properties. For example, crustal thickness variations occur not only across the East-West Antarctic boundary, but also between crustal blocks within West Antarctica. Modeling of mantle viscosity based on shear wave velocities shows a sharp lateral gradient from high to low viscosity in the Ross Embayment, a much more gradual gradient in the Weddell Embayment, and very low viscosities below Marie Byrd Land and the Amundsen Sea Embayment (ASE). Remarkable vertical and horizontal bedrock crustal motion velocity magnitudes, directions and patterns correlate spatially, in many aspects, with Earth property variations mapped by seismology. Within the ASE, extremely high upward velocities are flanked by subsiding regions – neither predicted by GIA models. Given the thin crust and low mantle viscosity, it is likely that this is not an LGM signal, which would have already relaxed, and uplift due to the elastic response to modern ice mass change clearly is important. As in other regions where rapid GIA-induced uplift has been measured, the crustal velocities in the Amundsen Embayment may also record a viscoelastic response to ice loss on decadal–centennial timescales. Along the East-West Antarctic boundary in the Ross Embayment, GIA-induced horizontal crustal motions are toward rather than away from the principal ice load center, correlating spatially with the strong lateral gradient in mantle viscosity. In the Weddell Embayment region, where crustal thickness is intermediate between East and West Antarctica and mantle viscosity values are moderate, crustal motions show the best match with predictions of GIA models. It is clear that lateral variations in Earth properties fundamentally control the isostatic response to ice mass changes in Antarctica. Ongoing integrated seismic-GPS studies are critical to developing the next generation of GIA models.""

Furthermore, geothermal activity is another good indicator of this magma as discuss at the following  Reporting Climate Science web article (with the two associated images):


http://www.reportingclimatescience.com/news-stories/article/second-paper-geothermal-heat-melting-west-antarctica.html

Best,
ASLR
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Earthquakes and climate change
« Reply #66 on: May 11, 2015, 11:21:16 PM »
Here is a link to an article about the Polenet –Anet; which is a GPS and seismic network spanning West Antarctica and the Transantarctic Mountains, the main mountain range separating East and West Antarctica:

http://polenet.org/?page_id=176

see also SERCE (Solid Earth Response and Influence on Cryogenic Evolution):
http://www.scar.org/scar_media/documents/meetings/33scar2014/33_WP15_SERCE_Report.pdf
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Earthquakes and climate change
« Reply #67 on: May 12, 2015, 06:25:39 PM »
A second major earthquake (not an aftershock) hit near Everest base camp today with a Richter magnitude of 7.3.  This may all just be nature or anthropogenic forcing could be acting as a stress riser (for frequency of return period and/or magnitude).

See:

http://www.nbcnews.com/storyline/nepal-earthquake/nepal-hit-7-3-magnitude-earthquake-panic-reported-kathmandu-n357481
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Timothy Astin

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Re: Earthquakes and climate change
« Reply #68 on: May 13, 2015, 08:56:45 AM »
The latest large Nepal earthquake is an aftershock. See the USGS summary:

http://earthquake.usgs.gov/earthquakes/eventpage/us20002ejl#general_summary

This page also gives a discussion of the underlying causes of large earthquakes in the region and their repeat times.

prokaryotes

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Re: Earthquakes and climate change
« Reply #69 on: May 17, 2015, 10:50:11 PM »
A clever fellow that goes by "prokaryotes" is more or less obsessed with the idea that for various reasons GW may trigger increased tectonic activity. I can't recall whether he is on these threads, but he frequents RC and has his own very good blog (which is mostly about climate science in general--a very impressive collection of sources, that):http://climatestate.com/

I'll see if I can track down one of his posts on this issue in particular.

It seems to me that SLR, in particular, must have some effect on pressure on tectonic plates at some point.

ETA: Here is the particular part of his site where he has collected some relevant videos: http://climatestate.com/category/climate-science/geosphere/geomorphology/

(He used to have a lot of links to actual research papers, but I can't seem to find those on his site anymore.)

Hej wili, thanks for the nice introduction, but m I obsessed with the idea? Basically the idea that there will be response from the Earth, due to isostatic rebound appears plausible, in particular from unloading of active faults.

Though, made a post on the topic here (note to mod, might be merged). http://forum.arctic-sea-ice.net/index.php/topic,1261.0.html

Btw. all the stuff should be still there @CS, not sure what you were looking for.

folke_kelm

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Re: Earthquakes and climate change
« Reply #70 on: May 18, 2015, 02:30:10 PM »
ASLR,

"
I imagine that folke_kelm must be pre-occupied doing something else today"
Indeed, i am occupied with other things most of my time, there are some small children and a job has to be done dealing with risk assessment and groundwater chemistry and some education too.
I am reading daily, but there is simply no time to write a comment, so please excuse me when i do not answer immediately.

I do not think that the discussion here has moved to some point of conclusion, at least not from my point of view. I still see some misconceptions about earthquakes, how they happen and why.

At first we have to distinguish between different geological phenomena cimate change is able to influence.
There are 1: slides 2: eruptions and 3: earthquakes.
All 3 may react to climate change in different ways. At first we have to consider about, what climate change possibly is able to change.
You ASLR; have provided us with a bunch of links, that give us an answer about this question.
Climate change is changing is rising the sea level, not equal but regional different, thus changing the vertical stress on plates, and human influence (not only climate change) is changing ground water level and again the vertical stress on plates. There is n discussion at all necessary about this fact.

Let us have a look at the consequences of this vertical stress change.

1: we begin with slides.
Here the limiting factor is internal cohesion (friction) inside the rock or sediment. This friction is strongly dependend of fluids in the free space between grains, in other words pore water pressure.
Increasing rain and rising ground water level will cause increasing pore water pressure and thus deminishing the internal friction, causing less shear stability of the rock. A slide may be the result as is seen frequently in California during El Nino years with increased rainfall.

2: Volcanism is always caused by vertical movement of hot mantle material or fluid rich partly melted masses from subducting in zones, where plates are recycled into the mantle (ring of fire) or in zones where crustal stretching takes place (mid ocean ridges).
In all cases we must take attention to the most important factor to generate liquid magma, pressure (static, not dynamic).
Liquid magma is, as i wrote earlier, generated when pressure is released, and only liquid magma is able to erupt.
The most important factor to release pressure is movement of plastic or fluid rich plastic mantle or crust material upwards in the crust. At a distinct pressure level the material will melt suddenly. this level is different for every material and every volcano.
You may translate pressure to a vertical stress, and now you see, that a melting ice cap, a melting glacier and if you want, draught and depleting of ground water will reduce pressure. IN the case of ice caps this will be at a rather high level.
But, please have in mind, that you must have material that is able to melt. Melting the ice cap has not caused any volcanic eruption anywhere in northern europe, it will not cause any eruption at the most places where we have ice caps today, simply because it will not move hot masses in the mantle. These movements take 10´s to 100´s of million years and they occure totally independend of any climate.

You see, a change in vertical stress can be caused by climate change. Let us now look at earthquakes. Here i disagree completely with the idea that climate change may cause an increase in frequency AND strength of earthquakes, let me explain why.
Nearly all earthquakes worth mentioning are caused by plate tectonics.
How does this work?
The different parts of the crust move independly over the more plastic deformed upper mantle. We know nowadays that the motor of this movement mostly is the pulling force of the subducting slab, not the pushing force of generating crust at mid oean ridges. This movement of plates create a nearly pure horizontal stress at places, where parts of crust  with different velocities meet. These are mostly transform or strike-slip faults (it does not really matter which type).
The horizontal stress generates elastic strain at places where the two plates are locked.
The relation between plate movement and rising elastic strain is nearly linear.
If you consider the plate movement as constant (it nearly is), then you see, that the buildup of strain is a result of two variables, the plate velocity and the time of locked movement (no movement at a certain place). The longer the time the bigger the quake.
Is climate change in form of rising sea level or changing ground water level capable to increase horizontal stress? This is the only possibility to add energy to the system of locked elastic strain.
If a changing load is not providing horizontal stress, it may nevertheles influence the magnitude or the frequency of earthquakes, but in a different way.
If a vertical stress component breakes a lock (or increased fluid pressure in the shear zone), the strain will be released as earthquake BEFORE it will occure naturally, and so it will have a lesser magnitude.
The way plate tectonics work is only able to react with diminishing magnitude and higher frequency or, if you provide a stronger locking, with higher magnitude but fewer quakes.
Higher vertical stress due to changes in water level is not at all able to provide more energy to the system, it can only change the way this energy is released.

Earthquakes due to isostatic rebound from removing icecaps are entirely different. They will occure, but they will never have the same magnitude as quakes due to plate movement. The unloading will  generate a new level of elastic strain which will be released at certain zones as moderate earthquakes until a new equilibrium is reached.
 

wili

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Re: Earthquakes and climate change
« Reply #71 on: May 18, 2015, 02:42:54 PM »
Hi prok! Good to see you chime in. I meant 'obsessed' in the best possible connotation!  ;D

Thanks for reminding us about the other thread and your excellent site, Climate State. People can find it here: http://climatestate.com/

Is there a sub-thread at CS where all the relevant pieces would be stored together? What would be the best terms to use to do a search on this topic?
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

Tor Bejnar

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Re: Earthquakes and climate change
« Reply #72 on: June 26, 2015, 05:45:57 PM »
Reverse glacier motion during iceberg calving and the cause of glacial earthquakes

Abstract:
Nearly half of Greenland’s mass loss occurs through iceberg calving, but the physical mechanisms operating during calving are poorly known and in situ observations are sparse. We show that calving at Greenland’s Helheim Glacier causes a minutes-long reversal of the glacier’s horizontal flow and a downward deflection of its terminus. The reverse motion results from the horizontal force caused by iceberg capsize and acceleration away from the glacier front. The downward motion results from a hydrodynamic pressure drop behind the capsizing berg, which also causes an upward force on the solid Earth. These forces are the source of glacial earthquakes, globally detectable seismic events whose proper interpretation will allow remote sensing of calving processes occurring at increasing numbers of outlet glaciers in Greenland and Antarctica.
Arctic ice is healthy for children and other living things.

Cate

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Re: Earthquakes and climate change
« Reply #73 on: April 08, 2016, 10:12:37 PM »
"Will climate change in the Arctic increase the landslide-tsunami risk to the UK?"

This is a major multi-year collaborative study focusing on the possibility of Storegga-type landslides happening as a result of Arctic warming. My interest in this is personal, as Newfoundland is also included in the study area. We know about landslip tsunamis in this corner of the Atlantic: in 1929, the south coast of Newfoundland suffered a tidal wave associated with an earthquake-landslip on the continental shelf. The 1929 event may or may not have been linked to climate change, of course, but it is very interesting to see that scientists are interested in finding out what the effects of climate change might be for the ocean floor up north.

http://projects.noc.ac.uk/landslide-tsunami/

This BBC article sets out the issue in layperson's terms.
http://www.bbc.com/earth/story/20160323-the-terrifying-tsunami-that-devastated-britain?ocid=global_earth_rss

prokaryotes

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Re: Earthquakes and climate change
« Reply #74 on: April 15, 2017, 04:19:15 PM »
Is there a sub-thread at CS where all the relevant pieces would be stored together? What would be the best terms to use to do a search on this topic?

You need to use the search and seek keywords, but there are not many updates, the last post was a 2014 interview, this http://climatestate.com/2014/10/16/methane-hydrate-destabilisation-is-clearly-a-real-worry-particularly-in-the-context-of-warming-ocean-waters-in-the-east-siberian-continental-shelf/

And then i recommend this lecture, Waking the Giant: Climate Force and Geological Hazards
 https://www.youtube.com/watch?v=xndhx7KpSU0

Recently
This study paper

Interaction between climate, volcanism, and isostatic rebound in Southeast Alaska during the last deglaciation https://www.researchgate.net/publication/306418361_Interaction_between_climate_volcanism_and_isostatic_rebound_in_Southeast_Alaska_during_the_last_deglaciation Summary posted here http://forum.arctic-sea-ice.net/index.php/topic,1952.0.html

Climate change may prevent volcanoes from cooling the planet
November 16, 2016 https://phys.org/news/2016-11-climate-volcanoes-cooling-planet.html
« Last Edit: April 15, 2017, 04:26:47 PM by prokaryotes »

wili

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Re: Earthquakes and climate change
« Reply #75 on: April 15, 2017, 06:42:49 PM »
Thanks, prok!
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."