Himalayan Earthquakes: Role of Tibetan Plateau

[billiards]

This is just a shameless plea for people to share their knowledge/ references (web links would be good ) regarding Himalayan Earthquakes. I want to know how and where they are generated, I am particularly interested in the role that the Tibetan plateau has to play.

So far I have it that India is being subducted beneath Tibet, the crust beneath Tibet seems to be unusually plastic and it is extending at right angles to the subduction. There is debate as to where the strain energy is released which causes earthquakes: people have assumed that the release of compressional strain accumulating close to the Greater Himalaya has been responsible for earthquakes, but now there is a group whi suggest that a 'significant fraction of the southernmost 500 km of the Tibetan plateau participates in driving great ruptures'.

(Feldl & Bilham, Great Himalayan earthquakes and the Tibetan plateau, Nature, Nov 2006)

 

[Astronuc]

Start here - http://geology.er.usgs.gov/eastern/plates.html

The Indian tectonic plate is being pushed north by the African and Australian plates into the Eurasian plate. The Himalayas form part of the region between the Indian plate and Eurasian plate (this includes the Pamirs and Himalayas). The Australian plate is particularly active as is evident from the activity along the Sunda trench along the eastern and southern borders of Indonesia. December 2004 Tsunami - http://iri.columbia.edu/~lareef/tsunami/

http://geology.er.usgs.gov/eastern/plateref.html

http://pubs.usgs.gov/gip/dynamic/dynamic.html

http://pubs.usgs.gov/imap/2800/ - downloadable map


Massive Himalayan Earthquake Overdue, Scientists Conclude

Anomalous Intensities in the Gangetic Plain Following Great Himalayan Earthquakes

This might be of interest, but one has to register.

Monitoring the Himalayan Earthquake Zone
http://www.cosmeo.com/videoTitle.cfm?guidAssetId=2DBE65B4-1AE2-48BC-957F-7E0C5F69A599&&nodeid=

Now somewhere I have some information of Pakistan and India's research.

 

[billiards]

thanks astronuc, those links were pretty helpful, the more specific ones to the himalayas especially.

cheers

 

[Andre]

Even more interesting are the things, not published. A friend of mine doing his BSc thesis, found out that the collision of India roughly 50 ma ago with the asian continent resulted in an...accelleration of the plate tectonics

 

[matthyaouw]

I wonder what role low angle thrust faults play, as they seem fairly common in large mountain belts.

Even more interesting are the things, not published. A friend of mine doing his BSc thesis, found out that the collision of India roughly 50 ma ago with the asian continent resulted in an...accelleration of the plate tectonics

Sounds interesting. Are you talking about global changes?

 

[Andre]

Not really, I think. The forming of the Himalaya has been thought to be forming a major carbon dioxide sink, because of the increased exposure of the rock to weathering. This would have decreased the CO2 levels in the atmosphere, which would have triggered the transition to cooler climates in the Eocene and ultimately the Quartenary ice age ages.

Problem is that several fossil leaf stomata proxies independently from each other confirm that the CO2 levels during the Tertiary were already down, comparable to modern levels, I discussed that in another thread. So another beautiful hypothesis down the drain.

It occurs to me that the devellopments in geologic/ paleo climate research are so rapid and divers that nobody has the overal picture anymore, especially about cleaning up the mess of failed hypotheses, which ideas linger on and poison the minds of future researchers, ultimately making it impossible to discover what really happened.

edit:
But concerning the original subject, I'd be very interested in the Pleistocene chronology of the seismic activities. Our little pulsating equator hypothesis for the ice ages would elict a prediction that the most active tectonic periods would be at the onset and termination of interglacials.

 

[Astronuc]

Pakistan sits astride the tectonic intersection of the India and Arabian plates with the Eurasian plate. As a result they are expected to and do experience some significant earthquake activity.

Here is the information on the geology and tectonic zones of Pakistan.

http://www.gsp.gov.pk/pakistan/index.html
http://www.gsp.gov.pk/pakistan/tectonics_zones.html


Geological Survey of India
http://www.gsi.gov.in/


Finding accessible material about Tibet or in China on-line is very difficult, but one can find articles in ACTA SEISMOLOGICA SINICA published by Springer.

A tectonic stress map of China and adjacent regions from earthquakes occurred during 2000∼2004


Present-day Movement and Tectonic Strain Rate Field of Active Crustal Blocks in China Continent in A Window on the Future of Geodesy
Proceedings of the International Association of Geodesy IAG General Assembly Sapporo, Japan June 30 – July 11, 2003

But there is this -

A second look at the geologic map of China: the "Sloss approach"
http://pvermees.andropov.org/noble/chinasloss/

 

[billiards]

Even more interesting are the things, not published. A friend of mine doing his BSc thesis, found out that the collision of India roughly 50 ma ago with the asian continent resulted in an...accelleration of the plate tectonics

Really? Sounds a bit iffy to me. But then agian, do you think this might explain why the Himalayas are higher than the Alps?

 

[Astronuc]

Really? Sounds a bit iffy to me. But then agian, do you think this might explain why the Himalayas are higher than the Alps?

Perhaps there was more energy/force in pushing India into Asia, than Africa into Eruope.

90 million years ago India rifted away from Madagascar and began its rapid movement northward, ultimately colliding with Asia between 55-50 million years ago. During the late Cretaceous (80 - 65 mya), India was moving at rates of more than 15 cm/year. No modern plate moves that fast. India's northward race towards Asia may be something of a plate tectonic speed record. The reason it moved so quickly was because it was attached to a large oceanic slab of lithosphere that was subducting beneath the southern margin of Asia.

http://www.scotese.com/indianim.htm

It would appear that the African plate did not move quite as much or as fast as the Indian plate. Also the Alps was formed with other ranges.

The Alpine orogeny (sometimes also called Alpide orogeny) is an orogenic phase in the Tertiary that formed the mountain ranges of the Alpide belt. These mountains include (from west to east) the Atlas, the Pyrenees, the Alps, the Dinaric Alps, the Hellenides, the Balkan, the Taurus, the Caucasus, the Alborz, the Zagros, the Hindu Kush, the Pamir, the Karakoram, and the Himalayas. Sometimes other names occur to describe the formation of separate mountain ranges: for example Carpathean orogeny for the Carpathians, Hellenic orogeny for the Hellenides or the Himalayan orogeny for the Himalayas.

http://en.wikipedia.org/wiki/Alpine_orogeny

This might be of interest
http://www.geophysik.uni-muenchen.de/research/seismics/transalp

http://titan.minpet.unibas.ch/aliens/smpm/Abstr791.pdf

http://www.uibk.ac.at/geologie/staff/pu_ortner_en.html

It appears that there is not shortage of studies on tectonics and mountain formation.