Res2dinv startime
Accelerating rates of geophysical signals (e.g., seismicity and deformation) preceding large-scale dynamic failure can serve as proxies for damage accumulation in the Failure Forecast Method (FFM). Their number and energy increase non-linearly, ending in a system-sized catastrophic failure event. Vasseur, Jérémie Wadsworth, Fabian B Lavallée, Yan Bell, Andrew F Main, Ian G Dingwell, Donald BĮlastic waves are generated when brittle materials are subjected to increasing strain. Heterogeneity: The key to failure forecasting. Our results show that this variability may be explained, and the reliability and accuracy of forecast quantified significantly improved, by accounting for material heterogeneity as a first-order control on forecasting power. In particular, the FFM has been used with only variable success to forecast failure scenarios both in the field (volcanic eruptions and landslides) and in the laboratory (rock and magma failure). These results have significant implications in a broad range of material-based disciplines for which failure forecasting is of central importance. We experimentally demonstrate that the accuracy of failure prediction increases drastically with the degree of material heterogeneity. We generate a suite of synthetic samples with variable heterogeneity, controlled by the gas volume fraction. Here we test the hypothesis that the style and mechanisms of deformation, and the accuracy of the FFM, are both tightly controlled by the degree of microstructural heterogeneity of the material under stress. Dingwell, Donald B.Įlastic waves are generated when brittle materials are subjected to increasing strain. Heterogeneity: The key to failure forecasting It is, however, more difficult to apply the method to multiple acceleration patterns. For explosions preceded by a single phase of seismic acceleration, we obtain accurate and reliable forecasts using approximately 80% of the whole precursory sequence. We test the method on precursory accelerations of long-period seismicity prior to vulcanian explosions at Volcán de Colima (Mexico). The spread of the a posteriori probability density function of the prediction time and its stability with respect to the observation time are used as criteria to evaluate the reliability of the forecast. As output, it provides the probability of the forecast time at each observation time before the eruption. The probability distributions of the data deduced from the performance of this classification are used as input. We use a Bayesian approach based on the FFM theory and an automatic classification of seismic events. In this study, we present a rigorous approach of the FFM designed for real-time applications on volcano-seismic precursors.
#Res2dinv startime series
Until now, most of the studies have presented hindsight forecasts based on complete time series of precursors and do not evaluate the ability of the method for carrying out real-time forecasting with partial precursory sequences. This method consists in adjusting an empirical power law on precursory patterns of seismicity or deformation.
Many attempts for deterministic forecasting of eruptions and landslides have been performed using the material Failure Forecast Method (FFM). Real-time eruption forecasting using the material Failure Forecast Method with a Bayesian approachīoué, A. This approach should be employed in place of the FFM to provide reliable quantitative forecasts and estimate their associated uncertainties. We show that a Generalized Linear Model method provides higher-quality forecasts that converge more accurately to the eventual failure time, accounting for the appropriate error distributions. Here we use synthetic and real data, recorded in laboratory brittle creep experiments and at volcanoes, to show that the assumptions of the FFM are inconsistent with the error structure of the data, leading to biased and imprecise forecasts. The Failure Forecast Method (FFM), which linearizes the power-law trend, has been routinely used to forecast the failure time in retrospective analyses however, its performance has never been formally evaluated. Power-law accelerations in the mean rate of strain, earthquakes and other precursors have been widely reported prior to material failure phenomena, including volcanic eruptions, landslides and laboratory deformation experiments, as predicted by several theoretical models. Forecasting volcanic eruptions and other material failure phenomena: An evaluation of the failure forecast methodīell, Andrew F.