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Paleo-earthquakes along the Cascadia subduction zone inferred from offshore sediments and Japan coastal tsunami deposits approximated to M9+ and ruptured the entire margin. However, due to the lack of modern megathrust earthquake records and general quiescence of subduction fault seismicity, the potential megathrust rupture scenario and influence of downdip limit of the seismogenic zone are still obscure. In this study, we present a numerical simulation of Cascadia subduction zone earthquake sequences in the laboratory-derived rate-and-state friction framework to investigate the potential influence of the geodetic fault locking on the megathrust sequences. We consider the rate-state friction stability parameter constrained by geodetic fault locking models derived from decadal GPS records, tidal gauge and levelling-derived uplift rate data along the Cascadia margin. We incorporate historical coseismic subsidence inferred from coastal marine sediments to validate our coseismic rupture scenarios. Earthquake rupture pattern is strongly controlled by the downdip width of the seismogenic, velocity-weakening zone and by the earthquake nucleation zone size. In our model, along-strike heterogeneous characteristic slip distance is required to generate margin-wide ruptures that result in reasonable agreement between the synthetic and observed coastal subsidence for the AD 1700 Cascadia Mw∼9.0 megathrust rupture. Our results suggest the geodetically inferred fault locking model can provide a useful constraint on earthquake rupture scenarios in subduction zones. This article is part of the theme issue 'Fracture dynamics of solid materials: from particles to the globe'. [ABSTRACT FROM AUTHOR]

ABSTRACT Permafrost is sensitive to climate change. In recent decades, a growing body of research has focused mainly on the study of permafrost thaw, but leaving the climate change in the permafrost region that has not been adequately assessed, which is of first importance for the research on permafrost thaw. Using gridded observations from the Climatic Research Unit ( CRU), in conjunction with the European Centre for Medium-Range Weather Forecasts Reanalysis Interim ( ERA-Interim) and Japanese 55-year Reanalysis ( JRA-55) data, this study investigates characteristics of air temperature evolution in the region of permafrost throughout the 20th century. Results show that yearly air temperatures in the permafrost region of the Northern Hemisphere experienced a statistically significant warming, with trends of 0.13 °C decade−1 for 1901-2014 and 0.40 °C decade−1 for 1979-2014. Winter air temperatures showed the greatest increase during 1901-2014, while autumn air temperatures increased the most during 1979-2014. In addition, increases in air temperature in high-latitude permafrost sub-region are greater than those in high-elevation permafrost sub-region, and air temperatures in the permafrost sub-region of Mongolia have the largest trend from 1901 to 2014, followed by those in Russia, Alaska, Canada, and China. Air temperatures in the permafrost region increased 1.7 times more than temperatures globally from 1901 to 2014, and underwent an increase at a rate of 0.32 °C decade−1 during the period 1998-2014, when the global warming hiatus occurred with a trend of 0.06 °C decade−1. This implies that permafrost thaw may have continued during the global warming hiatus period. The close agreement between CRU data and ERA-Interim and JRA-55 reanalysis data indicates good reliability of air temperature evolution characteristics. These results provide information relevant to climate change in the permafrost region, and are useful for researching and understanding historical permafrost change. [ABSTRACT FROM AUTHOR]