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Volcanic uplift, caused by the accumulation of magma in subsurface reservoirs, is a common precursor to eruptions. But, for some volcanoes, uplift of metres or more has not yet led to an eruption. Here we present displacement maps of volcanoes in the Galápagos Islands, constructed using satellite radar interferometry, that might help explain this dichotomy.(More)
Remeasurement of a triangulation network in the southern part of the New Madrid seismic zone with the Global Positioning System has revealed rapid crustal strain accumulation since the 1950s. This area experienced three large (moment magnitudes >8) earthquakes in 1811 to 1812. The orientation and sense of shear is consistent with right-lateral strike slip(More)
Probabilistic estimates of earthquake hazard use various models for the temporal distribution of earthquakes, including the 'time-predictable' recurrence model formulated by Shimazaki and Nakata (which incorporates the concept of elastic rebound described as early as 1910 by H. F. Reid). This model states that an earthquake occurs when the fault recovers(More)
[1] Postseismic displacements of as much as 14 cm were recorded by GPS measurements in the 3 months following the M W 7.6 1999 Chi-Chi, Taiwan earthquake. Data from 35 continuous and 90 campaign-surveyed stations, which show continued east over west thrusting, are analyzed to estimate the postseismic slip distribution and fault geometry. Assuming the(More)
Satellite radar interferometry data reveal strong localized uplift in a semi-circular pattern on the southwest flank of Fernandina volcano, Galápagos, where an eruption took place in January to April, 1995. The observations show a maximum decrease in radar range of 0.75 m, and they are consistent with a model of a shallow-dipping dike intrusion feeding this(More)
We use GPS displacements collected in the 15 months after the 1999 Chi-Chi, Taiwan earthquake (M w 7.6) to evaluate whether post-seismic deformation is better explained by afterslip or viscoelastic relaxation of the lower crust and upper mantle. We find that all viscoelas-tic models tested fail to fit the general features in the post-seismic GPS(More)
The horizontal displacements accompanying the 1906 San Francisco earthquake and the 1989 Loma Prieta earthquake are computed from geodetic survey measurements. The 1906 earthquake displacement field is entirely consistent with right-lateral strike slip on the San Andreas fault. In contrast, the 1989 Loma Prieta earthquake exhibited subequal components of(More)
Large earthquakes alter the stress in the surrounding crust, leading to triggered earthquakes and aftershocks. A number of time-dependent processes, including afterslip, pore-fluid flow and viscous relaxation of the lower crust and upper mantle, further modify the stress and pore pressure near the fault, and hence the tendency for triggered earthquakes. It(More)
The south flank of Kilauea volcano has experienced two large [magnitude (M) 7.2 and M 6.1] earthquakes in the past two decades. Global Positioning System measurements conducted between 1990 and 1993 reveal seaward displacements of Kilauea's central south flank at rates of up to about 10 centimeters per year. In contrast, the northern side of the volcano and(More)