Events in MathSys and Complexity Science
This is a calendar page detailing events within the MathSys CDT. It also acts as a booking diary for the Seminar Room D1.07. To book D1.07 please email Sheetal.Sharma@warwick.ac.uk
Please note that your event booking is for D1.07 only. The adjacent common room is a private area for the MathSys Centre that cannot used as part of your booking.
MathSys CDT events have priority for D1.07 room bookings.
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Complexity Forum: "The New Geophysics of a Crack-Critical Earth" Stuart Crampin (Edinburgh)
TITLE: The New Geophysics of a Crack-Critical Earth
SPEAKER: Stuart Crampin (Edinburgh)
ABSTRACT:
Stress-aligned shear-wave splitting (seismic birefringence) is widely observed in almost all in situ rocks throughout the ~30 km-thick crust of the Earth. Caused by propagation through the fluid-saturated stress-aligned grain-boundary cracks in crystalline rocks and aligned pores and pore-throats in sedimentary rocks, the degree of splitting indicates that microcracks are so closely spaced that all rocks verge on fracture-criticality and failure by fracturing and earthquakes. Verging on criticality is one of the defining characteristic of critical-systems. Critical-systems are a New Physics (a New Geophysics) which imposes a range of fundamentally new properties on conventional subcritical physics/geophysics. Controlled by changes in stress-aligned fluid-saturated microcrack geometry, the new properties imply that the low-level pre-fracturing deformation of in situ rock: can be monitored by shear-wave splitting; future behaviour calculated/predicted by anisotropic poro-elasticity (APE), a model of microcrack evolution; and in some circumstances future behaviour controlled by feedback. Moreover, these new properties extend to all available space within the highly heterogeneous complicated crust of the Earth. These ideas are controversial as they supersede many conventional properties of the supposed brittle-elastic behaviour of the uppermost half of the crust. This is a fundamental new understanding of fluid/rock deformation. The overwhelming evidence for the New Geophysics will be discussed and the implications for both earthquake and hydrocarbon seismology suggested.