The Journal TECTONICS, VOL. 26, TC4005, doi:10.1029/2006TC001987, 2007 in an article
Active tectonics of the Beichuan and Pengguan faults at the eastern margin of the Tibetan Plateau by Alexander L. Densmore of the Institute of Hazard and Risk Research and Department of Geography,Durham University, Durham, UK. and others -
The 17 page detailed article concluded that ..."These observations support models for the formation and maintenance of the eastern plateau margin that do not involve major upper crustal shortening. They also suggest that activity on the margin-parallel faults in eastern Tibet may represent a significant seismic hazard to the densely populated Sichuan Basin.
Page 16 ...
Finally, our observations of fault activity in the late Pleistocene and Holocene have important implications for seismic hazard, particularly in the densely populated Sichuan Basin. We have shown evidence for surface-rupturing earthquakes along the Beichuan fault since 12–13 ka, (ie 12 to 13, 000 years ago) along the northern Pengguan fault since about 4 ka, and along the outhern Pengguan fault since 930 ± 40 yr BP.
The timing of the last earthquake along the Dayi fault and associated structures at the mountain front is unknown, but these faults show some evidence for late Quaternary slip. An additional
seismic hazard, not discussed here, is the possibility of coseismic rupture on blind or partially blind faults underlying the active Xiong Po and Longquan anticlines in the western Sichuan Basin (Figure 1 - see above) [e.g., Burchfiel et al., 1995]. With the exception of the 1933 Diexi earthquake [Chen et al., 1994] and the 1976 Songpan earthquake series [Jones et al., 1984], the Longmen Shan region has had little historical seismicity [Chen et al., 1994]. This study shows
that this quiescence may not be representative of the longer timescales (104 yr) relevant to geomorphology.
Remarkably when Lord Patel was at school Wegeners hypothesis of Continental Drift was mentioned only as an example of a theory that was fanciful and could not be supported by geological evidence.
It was not until the 1960's that the ideas of Arthur Holmes' (Durham University Geological Lab is named after him) who elaborated on Wegener's idea of an African - Brazilian land bridge in his his book Principles of Physical Geology (1944) which concluded with a chapter about continental drift that his ideasstarted to receive serious attention. Greater understanding of the ocean floor and the discoveries of features like mid-oceanic ridges, geomagnetic anomalies parallel to the mid-oceanic ridges, and the association of island arcs and oceanic trenches occurring together and near the continental margins, suggested convection might indeed be at work.
These discoveries and more led Harry Hess (1962) and R.Deitz (1961) to publish similar hypotheses based on mantle convection currents, now known as "sea floor spreading". hess who was in the US Navy had used magnetic instruments (mangnetometers) adapted from airborne devices developed during WWII to detect submarines, began recognizing odd magnetic variations across the ocean floor which rsulted in his publishing in 1962 details of the Mid Atlantic Ridge.
Then in In 1967, W. Jason Morgan proposed that the Earth's surface consists of 12 rigid plates that move relative to each other. Two months later, in 1968, Xavier Le Pichon published a complete model based on 6 major plates with their relative motions.
This followed on the observations of a Tasmanaina oil geologist Samual Warren Carey, 1912-2oo2 whose field studies resulted in his publication of (1958) A Tectonic Approach to Continental Drift published in the Proceedings of the Continental Drift Symposium (Hobart 1956) - followed by a very influential lecture tour in USA and UK in 1960.
It is remarkable that in a brief lifetime what was considered an absurd hypothesis has proved to be so powerful that it can predict earthquakes.
Another example where the Laws of Nature are not determined by the popular vote and that a single or very few determined, honest and rigorous searchers for the truth can confound scientific orthodoxy.
A sobering thought after the gobshite spouted in support of the Human Embryology and Fertilisation Bill these last 2 days.
UPDATE Thursday 22nd May 2008 fashionista Rodney Fitch of trendy shop fitters Fitch & Co was on Peter Day's excellent "In Business" on BBC 4 and referred to " the tectonic plates of retailing are moving" ... by which he probably means things are changing. That or his designs for Terminal 5 shops look like they've just been struck by an earthquake.
AND ANOTHER : Just discovered a good site All of My Faults Are Stress-Related by Kim Hannula who gives a handy, clear and simple explanation of the "Tectonics of the May 12 Sichuan earthquake" dated Monday, May 12, 2008.