HR: 16:45h
AN: NG34A-04 INVITED    [Abstracts]
TI: Scaling, universality and spatio-temporal clustering in seismicity and rock fracture phenomena
AU: * Davidsen, J
EM: davidsen@phas.ucalgary.ca
AF: Complexity Science Group University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
AB: In this talk, I will discuss new methods from nonlinear sciences and complex network theory to characterize temporal and spatio-temporal clustering of point processes with a particular focus on their application to seismicity and rock fracture. Many striking features of natural processes can be portrayed as patterns or clusters of localized events. A generic attribute in all these cases is that one event can trigger or somehow induce another one to occur - or possibly numerous further events. Sometimes, an accounting of causal connections between clustered events is explicitly rationalized by the microscopic state and rules of the dynamical system. More often than not, though, the causal connections cannot be resolved from the data at hand and remain ambiguous. Thus, one is confronted with inferring a plausible causal structure from clusters of localized events without a detailed or "fundamental" knowledge of the true microscopic dynamics. I will present a method to search for such signs of causal structure in spatio-temporal data making minimal a priori assumptions about the underlying microscopic dynamics. For earthquakes, the method allows to recover the scaling of the rupture length with magnitude. Moreover, I will present a detailed statistical analysis of acoustic emission time series from a range of rock fracture experiments. In all considered cases, the waiting time distribution can be described by a unique scaling function indicating its universality. This scaling function is even indistinguishable from that for earthquakes suggesting its general validity for fracture processes independent of time, space and magnitude scales.
DE: 0550 Model verification and validation
DE: 3235 Persistence, memory, correlations, clustering (3265, 7857)
DE: 4475 Scaling: spatial and temporal (1872, 3270, 4277)
DE: 5104 Fracture and flow
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Nonlinear Geophysics [NG]
MN: 2007 Fall Meeting