Not volcanic or subterranean but certainly geo-
and socio-logic, by coincidence in this morning's
Guardian
http://www.guardian.co.uk/climatechange/story/0,,1815733,00.html,
read minutes before Ilan's message, is a report
that two million cubic metres of the Eiger in the
Bernese (Swiss) Alps is showing signs of cracking
away from the mountain due to climate change and
threatening landslides that in turn, it is
feared, will block glacial outflow and water
supplies to neighbouring towns. The report is
quoting Hans-Rudolf Keusen, "a geologist monitoring the situation".
James
At 20:38 07/07/2006, you wrote:
>On 4 January 2005, David Crichton asked this
>list "whether the frequency and severity of
>tsunamis might increase in the longer term due
>to climate change?" List archives are at
>http://www.jiscmail.ac.uk/cgi-bin/webadmin?A1=ind05&L=natural-hazards-disasters
>and see #154 for emails on this topic.
>
>The recent newspaper article appended below
>addresses this topic; however, I have just
>spoken to Allen Glazner
>http://www.geosci.unc.edu/faculty/glazner/glazner.html
>(not "Alan" as quoted) and he said that this
>media interest relates to his 1999 paper:
>
>A.F. Glazner, C.R. Manley, J.S. Marron, and S. Rojstaczer
>"Fire or ice: Anticorrelation of volcanism and
>glaciation in California over the past 800,000 years"
>Geophysical Research Letters, vol. 26 , no. 12 , pp. 1759-1762.
>
>Compilation of published ages of Quaternary
>volcanism in eastern California indicates that
>volcanism was episodic, with maxima occurring
>during interglacial periods. The smoothed age
>distribution shows peaks at 10, 100, 185, 320,
>and 690 kyr, corresponding to interglacial
>cycles 1, 5, 7, 9, and 17. This implies that
>volcanism was modulated by changes in climate,
>although the processes that link the two are not
>well understood. Several factors, including
>transient loads imposed across rugged topography
>by ice and water and changes in groundwater
>regime, may provide the link. Although climatic
>modulation of volcanism is generally tied to
>changes in sea level, these data indicate that
>even volcanoes far from the coast can be affected by climatic change.
>
>Two other references (from the above paper) are:
>
>McGuire, W. J., Howarth, R. J., Firth, C. R.,
>Solow, A. R., Pullen, A. D., Saunders, S. J.,
>Stewart, I. S. and Vita-Finzi, C. 1997
>Correlation between rate of sea-level change and
>frequency of explosive volcanism in the Mediterranean. Nature 389, 473-476.
>
>Rampino, M.R., S. Self, and R.W.
>Fairbridge. 1979. "Can Rapid Climatic Change
>Cause Volcanic Eruptions". Science, vol. 206, pp. 826-829.
>
>A reminder that weather affects volcanism too:
>
>Mason, B.G., D.M. Pyle, W.B. Dade, and T.
>Jupp. 2004. "Seasonality of volcanic
>eruptions", Journal of Geophysical Research,
>vol. 109, http://www.agu.org/pubs/crossref/2004/2002JB002293.shtml
>
>Perhaps time for more collaborations amongst
>geologists and atmospheric scientists along with, of course, social scientists.
>
>Ilan
>
>----------------------
>
>http://www.canada.com/topics/news/national/story.html?id=0447a0d1-63be-4f15-8992-96131e57853c&k=42084
>
>Climate change could cause earthquakes and volcanic eruptions, scientists say
>
>Dennis Bueckert, Canadian Press
>Published: Monday, July 03, 2006
>Article tools
>
>OTTAWA (CP) - So the warnings of harsher heat
>waves, stronger hurricanes and rising seas fail
>to impress. How about volcanic eruptions in the
>Arctic, or a tsunami off the coast of Newfoundland?
>
>The latest scientific discipline to enter the
>fray over global warming is geology.
>
>And the forecasts from some quarters are
>dramatic - not only will the earth shake, it will spit fire.
>
>A number of geologists say glacial melting due
>to climate change will unleash pent-up pressures
>in the Earth's crust, causing extreme geological
>events such as earthquakes, tsunamis and volcanic eruptions.
>
>A cubic metre of ice weighs nearly a tonne and
>some glaciers are more than a kilometre thick.
>When the weight is removed through melting, the
>suppressed strains and stresses of the underlying rock come to life.
>
>University of Alberta geologist Patrick Wu
>compares the effect to that of a thumb pressed
>on a soccer ball - when the pressure of the
>thumb is removed, the ball springs back to its original shape.
>
>Because the earth is so viscous the rebound
>happens slowly, and the quakes that occasionally
>shake Eastern Canada are attributed to ongoing
>rebound from the last ice age more than 10,000 years ago.
>
>Melting of the ice that covers Antarctica or
>Greenland would have a similar impact, but the
>process would be accelerated due to the human-induced greenhouse effect.
>
>"What happens is the weight of this thick ice
>puts a lot of stress on the earth," says Wu.
>"The weight sort of suppresses the earthquakes
>but when you melt the ice the earthquakes get triggered."
>
>When a quake happens under water it can cause a
>tsunami. Wu said melting of the Antarctic ice is
>already causing earthquakes and underground
>landslides although they get little attention.
>He predicted climate warming will bring "lots of earthquakes."
>
>When the glaciers melt, the reliquified water
>causes sea levels to rise and increases the
>weight on the ocean floor, which could also have
>an effect on the grinding tectonic plates deep below the surface.
>
>The Earth's crust is more sensitive than some
>might think. There are well-documented cases of
>dams causing earthquakes when the weight of the
>water behind a dam fills a reservoir.
>
>Alan Glazner, a volcano specialist at the
>University of North Carolina, said he was
>initially incredulous when he found a link
>between climate and volcanic activity off the coast of California.
>
>"But then I went to the library and did some
>research and found that in many places around
>the world especially around the Mediterranean
>they see similar sorts of correlations."
>
>"When you melt glacial ice, several hundred
>metres to a kilometre thick . . . you've
>decreased the load on the crust and so you've
>decreased the pressure holding the volcanic conduits closed.
>
>"They're cracks, that's how magmas gets to the
>surface . . . and where they hit the surface, that's where you get a volcano."
>
>No one has claimed that the Christmas tsunami of
>2004 was triggered by rising sea levels. But
>that event seems to have sparked new interest in
>the links between climate and geology.
>
>"All over the world evidence is stacking up that
>changes in global climate can and do affect the
>frequencies of earthquakes, volcanic eruptions
>and catastrophic sea-floor landslides," says
>British geologist Bill McGuire, writing in New Scientist magazine.
>
>"Not only has this happened several times
>throughout Earth's history, (but) the evidence
>suggests it is happening again," says McGuire,
>professor of geological hazards at University College in London.
>
>Glazner said the main impact of glacial melting
>is due to reduced weight on the places losing
>glaciers rather than the increased weight on the ocean floor.
>
>"If you melt that glacier and the water runs
>into the oceans, that water is spread over the
>entire surface of the ocean and it might add a
>millimetre to the thickness of the oceans or
>something, but you've taken a kilometre off of
>that place where the glacier used to be."
>
>© The Canadian Press 2006
|