Field of Research:
Geology
In Germany:
01.06.2008 -
31.08.2008
Host's project description
Professor John Suppe is one of the foremost structural geologists. He and his students have made ground-breaking advances in our understanding of the deformation of the Earth's crust. These advances have come largely from the development of new theory in combination with conceptually novel observations and analyses in actively deforming regions such as California, Taiwan, far western China and the Niger delta, as well as the planet Venus. Suppe is known for his founding and subsequent leadership in the field of "fault-related folding" which has shown in the last two decades that the large folds characteristic of the margins of compressive mountain belts form by a rich variety of processes involving the propagation and displacement of non-planar faults, in contrast with classic ideas that folds form by buckling of layered media. Thus we now understand that large folds grow by the summation of the displacements in thousands of large earthquakes, each contributing a few meters of sudden fold growth. Fault-related folding theory has successfully predicted the existence of a number of counter-intuitive phenomena that are now widely observed. Furthermore this theory has led to substantial practical applications in the assessment of earthquake-hazards, for example the recognition of major hidden active faults under Los Angeles, and new techniques of analysis of seismic images used in petroleum exploration and development worldwide. Professor Suppe has also made seminal advances in understanding the large-scale strength of the mountain belts and of great faults. In the 1980s he and his students made the startling discovery that the regional compression is nearly perpendicular to the great San Andreas and Sumatra faults, suggesting these faults are exceedingly weak relative to laboratory friction measurements. This discovery has been a prime motivation for the present San Andreas Drilling Project (SAFOD). In addition Professor Suppe and several of his colleagues at Princeton developed critical-taper wedge mechanics, which is arguably the most important advance in our understanding of the large-scale mechanics of mountain belts of the last half century. Critical-taper wedge theory has demonstrated that many mountain belts deform until they reach a critical regional surface slope governed by their strength. The mechanics of this process is analogous to that of the deformed wedges of soil or snow that develop in front of moving bulldozers. Suppe has recently made an additional theoretical break through by showing how to directly determine the absolute large-scale strength of mountain belts and of major faults from observed wedge tapers. Knowing these strengths is of fundamental importance to many fields but has been notoriously difficult to determine, with one of the few direct measurements at great depth coming from the German KTB deep borehole. Professor Suppe holds the honorary Blair Professorship of Geology at Princeton University, was elected a member of the US National Academy of Sciences, is an Honorary Professor of Nanjing University, and has been a visiting professor at Caltech (twice), National Taiwan University (twice), and University of Barcelona. He was selected as a Guest Investigator of the NASA Magellan Mission to Venus, is a Guggenheim Fellow, was selected Highly Cited Researcher by ISI, and has twice been cited for the best publication in five years in structural geology and tectonics by the Geological Society of America. During his stay in Germany Professor Suppe will be exploring issues of fault strength. Using geologic observations and new global computer models of the Earth's lithosphere and mantle he will address the longstanding problem of "Why the crust is so strong yet great faults are so weak" in collaboration with his host Professor Hans-Peter Bunge at the Geophysics group of LMU in Munich.
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National Taiwan University
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