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